Bulletin of the American Physical Society
54th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 68, Number 7
Monday–Friday, June 5–9, 2023; Spokane, Washington
Session N01: Poster Session II (4:00pm-6:00pm, PT)Poster
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Room: Exhibit Hall C |
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N01.00001: STRUCTURE AND PROPERTIES OF ATOMS, IONS, AND MOLECULES
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N01.00002: Fluorophore Self-Assembly in Liquid Crystals Mina Mandic, Kayla Winters, Charlotte Slaughter, Sophie Ettinger, Peter J Collings, Arjun G Yodh
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N01.00003: Precision Measurement of Hyperfine Constants and Isotope Shift of the Rb 6S State via a Two-Photon Transition Rajani Ayachitula, Mark D Lindsay, Monte D Anderson, Carl E Mungan, Carson D McLaughlin, Randy J Knize Using Doppler-free two-photon spectroscopy of the Rb 5S - 6S transition in a temperature-controlled vapor cell, for both naturally occurring isotopes, we have measured the hyperfine splittings and constants of the 6S state, and the isotope shift of the transition, to an accuracy of about 4 kHz. We locked a tunable microwave-driven EOM sideband of the 993 nm laser to an ultrastable very high finesse optical cavity, thus achieving microwave frequency accuracy for the relative laser tuning. The lineshapes are fit with a true Voigt profile. Our preliminary results are 717.200(4) and 1614.710(5) MHz for the hyperfine splittings, and 239.067(2) and 807.355(2) MHz for the hyperfine constants A, of the 85 and 87 Rb 6S state respectively, and -99.188(6) MHz for the isotope shift. These hyperfine constants are about 15 to 40 times more accurate than previously published results. |
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N01.00004: Microwave Spectroscopy of Low-l Singlet Strontium Rydberg States at Intermediate n Robert A Brienza, Yi Lu, Chuanyu Wang, Soumya K Kanungo, Tom C Killian, F B Dunning, Shuhei Yoshida, Joachim Burgdorfer Microwave spectroscopy is used to measure the relative energy separations between strontium n 1S0, n 1P1, n 1D2, and n 1F3 Rydberg levels for 50 ? n ? 70 with uncertainties, limited by possible stray electric fields, of a few tens of kilohertz. The microwave results are referenced to earlier measurements of term values for the n 1S0 state to obtain term values, and hence quantum defects, for the higher-l states and develop a revised set of self-consistent Rydberg-Ritz parameters that can be used to predict level separations over a broad range of n with much greater precision than is possible using earlier published Rydberg-Ritz parameters. The determination of accurate transition frequencies is central to the planning of quantum simulation experiments that involve microwave-coupled Rydberg levels, such as in the creation of Rydberg synthetic dimensions. |
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N01.00005: Measurement of the positronium 2P fluorescence decay rate Rebecca J Daly, Ross E Sheldon, David B Cassidy Measurements of positronium (Ps) energy levels and decay rates can be used to test QED theory and search for new physics [1]. Optical and microwave spectroscopy have been used to measure various Ps energy intervals [2-6] and Ps annihilation decay rates have been measured for the ground states [7,8] and the 2S excited state [9]. Here we report a measurement of the fluorescence decay rate of positronium (Ps) atoms in the 23P level. Ps atoms were optically excited to a Stark-mixed state containing both 2S and 2P components, in which the relative population was controlled via an applied electric field. A larger delayed electric field was then applied to induce rapid quenching and annihilation of the mixed states. By measuring the number of quenched atoms observed for different mixing field strengths we obtained the effective decay rate of the mixed states, from which the 2P decay rate can be obtained. The obtained result is consistent with theory but is not sufficient to test QED. We discuss possible improvements to the methodology that could allow for a more precise measurement. |
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N01.00006: Spectroscopy of metastable trapped 173Yb+ for quantum information and fundamental science Thomas Dellaert, Wesley C Campbell, Patrick J McMillin, Hassan Farhat The metastable 2F7/2 state in 171Yb+ is increasingly being utilized as a resource for quantum information processing, but the more complex (and potentially more useful) hyperfine structure of this state for the deformed-nucleus ytterbium-173 isotope is experimentally unexplored. Predictions, however, point to unique aspects of the hyperfine interaction in this case, including hyperfine quenching of the metastable state lifetime to a technologically attractive level and the potential to resolve a 4 orders of magnitude discrepancy in the nuclear magnetic octupole moment of ytterbium-173. We present initial spectroscopy of 173Yb+, and progress towards microwave spectroscopy of the metastable 2F7/2 state. |
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N01.00007: The diatomic molecular spectroscopy database Daniel Julian, Connor Chin, Ethan Franco, James Marini, Yueqian Wang, Jesus Perez Rios We present an updated version of our previous website dedicated to the molecular spectroscopy of diatomic molecules (https://rios.mp.fhi.mpg.de/index.php): A user-friendly website including spectroscopic constants of diatomic molecules beyond Herzberg's book and the NIST website. It is open, so researchers can register and upload new spectroscopic data to make a dynamic and up-to-date database for the community. The data is freely available and ready to be downloaded in any preferable format. The updated version incorporates a graphical user interface to perform machine learning studies with the data. The user can select any feature and train a machine-learning model to predict a given outcome. Therefore, in this way, bringing machine learning closer to spectroscopy. Similarly, we include more advanced plotting tools for a better user experience. |
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N01.00008: Measurement of the Rb 5S - 6S Transition via One-Photon M1 Excitation Mark D Lindsay, Carson D McLaughlin, Randy J Knize Using a laser induced fluorescence spectroscopy scheme with a collimated Rb atomic beam, we have made progress in our measurements of the Rb 5S - 6S transition, in both isotopes, with a one-photon M1 excitation at about 497 nm. We plan to measure for the first time the M1 transition amplitude to the Rb 6S state, and the atomic scalar and vector polarizabilities α and β of that state, using an applied external DC electric field, and compare these to theoretical calculations. |
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N01.00009: Analysis of Experimental Ni I and Ni II Spectra with Comparisons to Theoretical Collisional Radiative Calculations Brynna Neff, Steven Bromley, Stuart D Loch, Chad E Sosolik, Joan Marler Laboratory measurement of atomic spectra is necessary for benchmarking theoretical calculations, yet there are many elements for which the experimental data is incomplete. To this end, we studied the spectra of Ni I and II using the Compact Toroidal Hybrid experiment at Auburn University. This experiment allows us to observe emission lines under conditions which are appropriate for comparisons to collisional radiative calculations. We report here an analysis of the experimental spectra as well as comparisons to theoretical collisional radiative calculations, with a focus on the line intensity dependence upon electron temperature and density within the plasma. |
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N01.00010: Resolving High Order Tensor Interactions in C60 Fullerenes Dina Rosenberg, Lee R Liu, Jun Ye, Bryan Changala, David J Nesbitt, Timur V Tscherbul Lee R. Liu, Dina Rosenberg, P. Bryan Changala, David J. Nesbitt, Timur Tscherbul, Jun Ye |
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N01.00011: Experimental Study of Highly Excited 1Πg and 1Σg+ States of the Cesium Dimer Brendan A Rowe, Jacob T Stahovich, Adam D Hersh, Peter Wardach, Joel D Keen, A M Lyyra, Ergin H Ahmed We report the results of an experimental study of highly excited 1Πg and 1Σg+ electronic states of the 133Cs2 dimer. The rovibrational structure of these states was probed using the optical-optical double resonance (OODR) technique in which 133Cs2 molecules from thermally populated levels in the X1Σg+ ground state were excited through intermediate levels from either the B1Πu state or the mixed A1Σ+u ∼ b3Πu states. The probe laser resonance frequencies were determined by detecting laser induced fluorescence from the target states to the ground a3Σu+ triplet state. These resonance frequencies were used to calculate the rovibronic term values, which were in turn used to construct potential energy curves for each of the electronic states with the Rydberg-Klein-Rees method. The observed states were identified as 1Πg and 1Σg+ electronic states based on the selection rules for dipole allowed transitions that the line patterns in the recorded excitation spectra followed. |
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N01.00012: Experimental study of the 31Δg and 41Δg states of Rb2 Jacob T Stahovich, Brendan A Rowe, Phillip T Arndt, Peter Wardach, Adam D Hersh, John P Huennekens, A M Lyyra, Ergin H Ahmed We report a high-resolution experimental study of the highly excited 31Δg and 41Δg electronic states of the 85Rb2 dimer. Rovibrational levels of the two electronic states were probed using the optical-optical double resonance (OODR) technique by exciting 85Rb2 molecules from thermally populated levels of the X1Σg+ ground state through intermediate levels of the B1Πu electronic state. The resonances of the probe laser were observed by detecting the laser induced fluorescence (LIF) from the target states to the a3Σu+ triplet ground state. The 1Δg character of the two electronic states was confirmed by showing that the transitions to these states abide by 1Π - 1Δ dipole selection rules and by observing that their lowest rotational level is J = 2. Preliminary molecular constants and Rydberg-Klein-Rees (RKR) potential energy curves from the observed term values were calculated for each electronic state and compared with ab initio calculations. |
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N01.00013: Spectral line shaping by exoplanetary atmosphere Daniel Vrinceanu Exoplanets are discovered during occultation events. Spectral lines characteristic of stellar emissions are modified and shaped by traversing exoplanetary atmosphere. Several models for radiation transport are presented and compared with observational data. The relative contributions of scattering, absorption and collisional broadening by haze particles are discussed. Accurate measurements of the shape of stellar spectral lines provide critical information about the properties and composition of exoplanetary atmosphere. |
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N01.00014: High resolution continuous wave spectroscopy on the X2Π3/2 to A2Σ+ transition in nitric oxide Patrick Kaspar, Fabian Munkes, Philipp Neufeld, Lea Ebel, Yannick Schellander, Robert Löw, Tilman Pfau, Harald Kübler Within the scope of the development of a new kind of gas sensor, we employ Doppler-free saturated absorption spectroscopy on the X2Π3/2 to A2Σ+ transition in nitric oxide (NO) for different total angular momenta J on the P12 branch. Spectroscopy is performed in continuous wave operation at 226 nm in a 50 cm long through-flow cell. Via phase sensitive detection by a lock-in amplifier the hyperfine structure of the X2Π3/2 state of NO is partially resolved. The data is compared to previous measurements, showing good agreement. Investigation of the dependence of the spectroscopic feature on power and pressure, should yield hyperfine constants, natural transition linewidth and the collisional cross-section between NO molecules. |
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N01.00015: Unusual bound state of H2+ Shayamal Singh, Chris H Greene
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N01.00016: Electron Retroaction in the Dissociation of fixed in Space H2 and D2 Molecules Guillaume M Laurent, Spenser J Burrows, Itzik Ben-Itzhak, Benjamin Berry, Elio G Champenois, Reinhard Doerner, Jan Dvorak, Averell S Gatton, Wael Iskander, Kirk A Larsen, Robert R Lucchese, C. William McCurdy, Daniel Metz, Thomas N Rescigno, Hendrik Sann, Travis Severt, Niranjan Shivaram, Daniel S Slaughter, Miriam Weller, Joshua B Williams, Thorsten Weber Experiments employing the COLTRIMS technique in combination with VUV radiation from the Advanced Light Source (ALS) synchrotron that single-ionizes and dissociates hydrogen and deuterium molecules just above threshold have been carried out at several photon energies. We report on the asymmetry of the molecular frame photoelectron angular distribution (MFPAD) due to the post-photoionization interaction between the low-energy photoelectron and the parent molecular ion, which is known as the electron retroaction effect. We investigate the dependence of this asymmetry on the angle between the molecular axis and the polarization direction of the synchrotron radiation. We also report on how these MFPADs change with photoelectron energy. |
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N01.00017: Wigner Time Delay in Photoionization: A Simple 1D Model Study Karim I Elghazawy, Karim I Elghazawy, Chris H Greene In scattering theory, the Wigner time delay, calculated through phase shifts derivative, has been demonstrated to measure the amount of delay or advance experienced by an incoming particle during its interaction with the scattering potential [1]. Fetic, Becker, and Milosevic claim that this concept cannot be extended to include photoionization viewed as a half-scattering experiment [2]. Their argument is based on the lack of information about scattering phase shifts in the part of the wave function (satisfying the incoming-wave boundary condition) going to the detector. This work aims to test this claim by examining a photoionization process in a simple 1D model with a short-range symmetrical potential. Using time-dependent perturbation theory with a dipole interaction, the relevant wave packet of the outgoing particle is analyzed and compared to the free wave packet as a reference. Our findings reveal a time delay in the analytic form of the liberated particle wave packet determined directly through the scattering phase shifts. We further support this result by carrying out a numerical simulation for both the non-free wave packet and the free one. The amount of the observed time delay is found to be half of that appearing in a typical collision experiment. |
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N01.00018: Photoionization of Atomic Sodium for Astrophysics Thomas W Gorczyca, Connor Ballance, Nigel R Badnell, Steven T Manson, Matthew Burger, Orenthal Tucker, Liam Morrissey, Rosemary M Killen, Daniel W Savin Near-threshold photoionization of atomic Na has been of interest both for basic physics and for astronomical applications for more than 70 years, beginning with the pioneering calculations of Seaton in 1951 and the experimental work of Hudson and Carter in 1967. The existence of a Cooper minimum in the threshold region makes accurate computation of the near-threshold cross section and recombination rates problematic since the details of the very small photoionization cross section in the region of the minimum is highly sensitive to the details of the calculation, specifically, the multiconfiguration/multichannel many-body wave functions of the initial and final states. Here we theoretically quantify this Cooper minimum in detail and obtain reliable near-zero cross sections and rate coefficients in the photon energy range just above threshold. |
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N01.00019: Attosecond Time Delay Trends across the Isoelectronic Noble Gas Sequence Brock Grafstrom, Alexandra S Landsman The relationship between negatively charged halogens and their nobel gas counterparts has been of considerable interest to the study of attosecond time delays as it is well known that experimental time delay measurements are the sum of two separate delay components, with the first being the Wigner delay and the second being the coulomb laser-coupling delay. The study of negative halogens provides the experimental benefit of eliminating the coulomb laser-coupling delay, therby allowing direct measurements of an absolute Wigner time delay. Many experimental and theoretical analyses have been made regarding photoionization time delays in nobel gases, but very little literature has been published on photodetachment time delays in halogen atoms until recently. In this work, Relativistic Random Phase Approximation (RRPA) time delay calculations were performed for the negative ions Cl-, Br-, I- and compared to the nobel gases Ar, Kr, and Xe. |
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N01.00020: Energy dependent rotations in ATI from xenon with elliptically polarized light Edward F McManus, Michael Davino, Phi-Hung Tran, Tobias Saule, Thomas Weinacht, George N Gibson, Anh-Thu Le, Carlos A Trallero We present experimental and theoretical results of 3D VMI imaging of photoionization of Xenon with elliptically polarized femtosecond pulses centered of 800 nm in the non-adiabatic regime. Due to an increased resolution compared to prior 3D imaging experiments, we observe a strong energy dependent rotation within each ATI ring, as well as an angular offset between the center of mass of each ATI ring. The inter-ring rotation has been observed previously; however, the rotation within each ring |
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N01.00021: Measurement of Absolute Photoionization Cross Sections from the 7s and 7p Excited States of Atomic Ytterbium Bilal Shafique, Raheel Ali New studies of the absolute photoionization cross-sections from the two excited states (6s7s 1S0 and 6s7p 3P2) of neutral ytterbium (Yb I) are reported. The saturation technique has been implemented, in which the intensity of the exciting laser is kept fixed while that of the ionizing laser is varied using neutral density filters. The photo-ion signal from the excited state at and above the threshold region was recorded as a function of ionizing laser intensity. Two Hanna-type dye lasers along with a thermionic diode detector working in the space-charge limited mode were used for the measurements. In the first set of experiments, the population from the ground state (6s2 1S0) was promoted to the 6s7s 1S0 excited state (34350.65 cm-1) via a two-photon transition using the dye laser wavelength tuned at 582.2 nm. The ionization limit above the excited state lies at 50443.08 cm-1 which is accessed via single-photon transition using a 621.4 nm dye laser wavelength. A total of four channels in the continuum at 0.07 eV, 0.11 eV, 0.34 eV, and 1.49 eV excess photoelectron energies above the ionization threshold (I.P.) are accessed. For the former two, dye lasers tuned at 600 nm and 590 nm are used whereas for the later ones, frequency-doubled (532 nm) and –tripled (355 nm) outputs of the Nd:YAG laser is used. The photoionization cross sections at and above the I.P. have been measured using the saturation technique as employed in the first set of experiments. In the third set, photoionization cross sections from the 6s7p 3P2 excited state have been measured at and above the I.P. For the 6s7p 3P2 state (38551.2 cm-1), the I.P. is accessed via 840 nm dye laser wavelength and all the continuum channels are accessed using 720 nm, 590 nm, and 355 nm ionizing wavelengths at 0.25eV, 0.63 eV, 65 and 2.02 eV photoelectron energies, respectively. The measured photoionization cross-sections show a monotonic decrease above the first ionization threshold which is an interesting behavior whereas a higher value of cross-section at the ionization threshold means that the wave functions of the exited state and the continuum channels are strongly overlapped. To the best of our knowledge, all the photoionization cross-section measurements are reported for the first time. |
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N01.00022: Photodetachment of the Positronium Negative Ion (Ps-) and the 1D-wave e--Ps scattering Sandra J Ward Quintanilla, William Mitchell The photodetachment cross section of Ps- has been computed in both the length and velocity forms [1-5]. However, for small wave lengths there exists a discrepancy between the calculations of this cross section that used different types of wave functions [3-5]. To see if we could resolve this discrepancy, we computed the cross section. We extended the calculations of Refs. [1-3] by improving the accuracy of the bound-state and 1P continuum variational wave functions of the e- -Ps system. Also, since the continuum 1D wave function of the e--Ps system is needed for the two-photon detachment cross section of Ps- we have begun a Kohn variational calculation to determine 1D phase shifts for e--Ps scattering for energies below the Ps(n=2) threshold. |
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N01.00023: ATOMIC, MOLECULAR, AND CHARGED PARTICLE COLLISIONS
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N01.00024: The Science Gateway for Atomic, Molecular, and Optical Science (AMOS) Kathryn R. Hamilton, Klaus Bartschat, Igor Bray, Andrew Brown, Nicolas Douguet, Charlotte F Fischer, Jesus G Vasquez, Jimena D Gorfinkiel, Robert R Lucchese, Fernando Martín, Sudhakar Pamidighantam, Barry I Schneider, Armin Scrinzi An international group of atomic, molecular, and optical theorists are continuing to develop the AMOSGateway [1], a computational portal where practitioners can access a synergistic, full-scope platform for computational Atomic, Molecular, and Optical Science (AMOS). The gateway currently hosts several state-of-the-art software suites for computing atomic spectra, transition probabilities, electron and positron collision and photoionization processes, including short-pulse intense-field laser-atom/molecule interactions. It is powered by an advanced cyberinfrastructure based on open-source Apache Airavata framework to enable a flexible and easy-to-use platform for the broad AMOS community, as well as researchers and educators who are not computational AMOS scientists. The applications are directly accessed on the gateway, where they have been compiled on several NSF-supported compute systems. Users can access and modify input files for their own purposes and submit them for execution using an ACCESS AMOSGateway account. In addition, the gateway serves as an excellent vehicle to educate students in computational AMOS via hands-on calculations, and as a hub for material created by the developers for teaching, workshops, and conferences. We will report on the current status of the gateway and present hands-on demonstrations. |
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N01.00025: Free-free experiments: angular distributions of elastic and inelastic electron-helium scattering Brian Kim, Charles M Weaver, Nicholas L S Martin, Bruno A deHarak Free-free experiments investigate the emission and absorption of radiation during the collision of charged particles with atoms and molecules in a laser field. This process has been well described by the semi-classical Kroll-Watson approximation (KWA).2 In this work, we extend our previous tests of the KWA3 by measuring relative differ- ential cross sections for 350 eV electrons scattered both elastically and inelastically from He targets in the presence of a 1.17 eV laser field at various scattering angles up to 90?. Here, the energy loss of the inelas- |
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N01.00026: ULTRAFAST AND STRONG FIELD PHYSICS
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N01.00027: Control of the Rabi sideband patterns from transient excitation gratings in filament wake channels in a dense gas* Suyash Bajpai, Dmitri A Romanov, Robert J Levis In a dense gas, the filamentation at a crossing of two femtosecond laser beams results in transient gratings of ionic and excited-atom densities. The laser intensity grating produced by the interference affects the electron impact processes in a dense gas, which result in these excitation and ionization gratings. The excitation gratings are specific of the dense-gas setting; they are controlled by the crossing angle as well as by the phase delay between the beams. The presence of these gratings in the wake of the laser pulse can be verified by their effect on the Rabi sideband emission. When a picosecond probe laser pulse is incident normally on the grating, the oscillating electric field of the pulse couples with the transitions in the excited state manifold of the gas atoms, causing the emission of frequencies red-shifted and blue-shifted about the carrier frequency. This Rabi sideband radiation emitted by the grating lines interferes constructively to form a characteristic spatial-spectral pattern on a remotely placed screen. These patterns are modified by the crossing angle, inter-beam phase delay, the pump and the probe pulse characteristics, and the distance between the screen and grating. We demonstrate how the characteristics of the Rabi sideband patterns are quantitatively associated with the grating features. We also investigate how the Rabi sideband patterns are robustly controlled by the modification in probe pulse shape. |
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N01.00028: Investigating multiphoton resonances with Laser Induced Electron Diffraction Eric L Mullins, Pavan N Muddukrishna, Sajed Hosseini-Zavareh, Isaac Yuen, Su-Ju Wang, Cosmin Blaga, Chii-Dong Lin Photoionization of atoms or molecules in electromagnetic fields occurs via absorption of one or more photons. Once ionized, if the laser is linearly polarized, the photoelectron may revisit and recollide with the parent ion. This rescattering event can be elastic, inelastic or recombination. In recent years, the elastic channel has received considerable attention, as it facilitates the extraction of accurate electron-ion elastic differential cross sections from measured 3D photoelectron angular distributions, a technique called laser induced electron diffraction (LIED). Thus far, it was shown that LIED works very well in the strong field limit, when the return electron energy is exceeding 50-100 eV. Here, we report LIED measurements in the multiphoton regime in atoms and small molecules, performed at significantly lower electron return energies, and discuss the essential role of multiphoton resonances in LIED. |
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N01.00029: First principle simulation approach for attosecond XUV pump – XUV probe spectra for small organic molecules Gilbert Grell, Jesús González-Vázquez, Piero Decleva, Alicia Palacios, Fernando Martín
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N01.00030: A nonlinear optical signal electric field measurement setup for VUV excited molecules Eric H Liu, Siddhant Pandey, Francis F Walz, Niranjan Shivaram We describe an experimental setup for the measurement of the complete electric field of a third-order nonlinear optical signal from gas phase molecules excited by vacuum ultraviolet (VUV) pulses. A near infrared (NIR) femtosecond laser at a central wavelength of 800 nm is used to generate VUV pulses using the process of high harmonic generation in Argon. VUV mirrors with a special coating are used to reject 800 nm light and reflect 160 nm (5th harmonic of 800 nm) light for excitation of target molecules such as ethylene. A separate nonlinear probing beam consisting of NIR pulses is spatially and temporally overlapped with the VUV beam at the target. Multiple nonlinear optical probing schemes are used to probe ultrafast dynamics in the VUV excited molecules. In one scheme, we measure a four-wave mixing signal involving the VUV and the NIR pulses resulting in a signal at 400 nm. We discuss progress towards completely measuring the electric field of such nonlinear signals in VUV excited molecules. |
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N01.00031: Time-Resolving Attosecond Coherent Electron Motion Erik Isele Charge migration, the coherent motion of charge driven by purely electronic dynamics, may play an important role in chemical reactions and offer an avenue towards engineering reaction pathways. The typical energy splitting of valence states in small molecules is on the order of electron volts, which results in coherent dynamics on the attosecond timescale. Exploiting recent developments in attosecond x-ray pulse pair generation at the LCLS, we time-resolve charge migration in meta-aminophenol. An x-ray pump pulse ionizes the molecule, generating a coherent superposition of valence-ionized states. We then probe the hole density in the vicinity of the oxygen site through the amplitude of the resonant transition between the oxygen core electrons and the hole. The effect of the zero-point spread of the nuclear wavepacket on the dephasing of the coherent motion is observed. |
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N01.00032: Joint probability analysis of the dynamics of strong field ionization of atoms Igor Ivanov, Kyung Taec Kim, Anatoli S Kheifets We describe an approach to the description of time-development of the processes of ionization of |
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N01.00033: Correlation effects in O2 attosecond transient absorption Carlos A Marante Valdes, Andrew Short, Juan M Randazzo, Barry I Schneider, Jeppe Olsen, Luca Argenti Advances in attosecond technologies have opened the way to the experimental time-resolved study of correlated electronic excitations in atoms and molecules [1,2]. These experiments require a time-dependent wave-function approach to represent the coherent superposition of multiple ion-photoelectron pairs. To tackle this challenge, we have developed ASTRA (AttoSecond TRAnsitions), a molecular-ionization code based on a new transition-density-matrix formalism that allows for efficient algorithms to build the necessary observables in a close-coupling space [3], with the support of the LUCIA general configuration-interaction code [4] and the GBTOlib hybrid-integral library [5]. We apply ASTRA to study the ultrafast electron dynamics triggered in molecular oxygen by sequences of attosecond laser pulses. We focus in particular on the effect that electronic correlation has on the attosecond transient absorption spectrum of the laser-dressed molecule, across many ionization thresholds up to the the c 4Σu- ionic channel, within the Franck-Condon region. To compute the optical response of the dressed target, we propagate the wave function in a basis of essential Siegert states, which greatly accelerates the calculation without appreciably compromising its accuracy. Our computed photoionization and transient absorption spectra are compared with other theoretical and experimental results reported in the literature [6,7]. This work is supported by the DOE CAREER grant No. DE-SC0020311. The calculations used NERSC resources under the contract No. DE-AC02-05CH11231 and the award BES-ERCAP0024720. |
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N01.00034: Accurate semiclassical method for constructing photoelectron momentum distribution for atoms in intense few-cycle laser pulses Phi-Hung Tran, Anh-Thu Le, Van-Hung Hoang We present a semiclassical method for constructing photoelectron momentum distribution (PMD) for atoms in intense few-cycle laser pulses. In the method, the momentum distribution is modeled in two steps. The first step is strong-field ionization, and the second step is electron propagation in the combined atomic and laser fields within the Herman-Kluk semiclassical time evolution operator approach. The constructed PMD is compared very well to the exact numerical solutions of the time-dependent Schrödinger equation (TDSE) for different atoms (H, Ar, Ne, and Xe). Detailed analysis was carried out for rescattered electrons, which are responsible for the high-energy region. The excellent agreements with the TDSE enable this semiclassical method to retrieve the differential cross section of elastic scattering of the target ion. We also show that the model successfully produces the photoelectron holography, which implies that the interference between direct and rescattered electrons is well described. |
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N01.00035: XUV-pump IR-probe resonant shake-up ionization of helium Nicholas Lewis, Luca Argenti Helium is an ideal prototype to investigate electronic correlation in ionization processes with high experimental [1-3] and theoretical accuracy~[3-6]. Pump-probe ionization processes through doubly excited states (DES), in particular, open a window on static correlation resolved in time~[6]. In this work we explore the role of DES in XUV-pump IR-probe ionization processes accompanied by shakeup, which is still largely unexplored. Indeed, only the recent advent of high-repetition-rate and intense XUV pulses from Free-Electron Lasers (FELs) have opened the way to study non-linear effects in coincidence measurements with high statistics~[7]. Here, we present emph{ab initio} calculations of the photoelectron signal in the single ionization of helium by intense FEL XUV radiation, in the presence of an IR dressing pulse, as a function of the photon and electron energy. Thanks to the long duration and tunability of the XUV pulse, it is possible to isolate the multiphoton shake-up signal associated to a specific intermediate DES. For this work, we have implemented a periodic extraction of the external portion of the wavefunction, which allows us to simulate the ionization of long-lived metastable states in the presence of pulses several tens of femtoseconds long within comparatively small quantization boxes. |
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N01.00036: Enhanced cutoff energies for direct and rescattered strong-field photoelectron emission of plasmonic nanoparticles Erfan Saydanzad, Jeffrey A Powell, Adam M Summers, Seyyed Javad Robatjazi, Carlos Trallero A Trallero, Matthias Kling, Artem Rudenko, Uwe Thumm We here demonstrate the generation of photoelectrons (PEs) by exposing plasmonic nanostructures to intense laser pulses in the infrared (IR) spectral regime and analyze the susceptibility of PE spectra to competing for elementary interactions for direct and rescattered photoemission pathways. Specifically, we measured and numerically simulated emitted PE momentum distributions from prototypical spherical gold nanoparticles (NPs) with diameters between 5 and 70 nm generated by short laser pulses with peak intensities of 8×1012 and 1.2 ×1013 W/cm2 [1,2], demonstrating the shaping of PE spectra by the Coulomb repulsion between PEs, accumulating residual charges on the NP, and induced plasmonic electric fields[2]. We scrutinized the controllability of the direct and rescattered PE yield and cutoff energy by tuning the laser intensity and NP size. Compared to well-understood PE cutoff energies for strong-field photoemission from gaseous atomic targets (10 × the ponderomotive energy), our measured and simulated PE spectra reveal a dramatic cutoff-energy increase of two orders of magnitude with a significantly higher contribution from direct photoemission. Our findings indicate that direct PEs reach up to 93% of the rescattered electron cutoff energy, in contrast to 20% for gaseous atoms, suggesting a novel scheme for the development of compact tunable tabletop electron sources [3]. |
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N01.00037: LASERS AND QUANTUM OPTICS
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N01.00038: IonSim.jl: Julia framework for simulating the dynamics of Trapped-Ion systems Kristian D Barajas, Joseph Broz, Neil Glikin, Justin Phillips * IonSim.jl integrates experimentally-driven functionality with the abstract state space framework and numerically efficient operations of QuantumOptics.jl |
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N01.00039: Quantum criticality in the tricritical Dicke model. Diego A Fallas Padilla, Han Pu The Dicke model, which describes a quantized light field interacting with an ensemble of two-level atoms, is a cornerstone model of quantum optics. It illustrates the collective phenomena of superradiance in a non-transient way through the second-order superradiant phase transition observed when the light-atom interaction strength is varied. Here we present a generalization of this model, the tricritical Dicke model (TDM), where the transition between the normal and superradiant phases can be tuned from second- to first-order, across a tricritical point. This is achieved by replacing the two-level atoms with three-level atoms. A full characterization of all different critical manifolds is done through the determination of the scaling behavior of the different observables. Additionally, we consider the robustness of these rich phase diagram regions when losses are incorporated into the model, leading to multiple stable phases and a modification of the phase boundary geometries. The richness of the phase diagram of the TDM and other associated generalized Dicke models makes them attractive candidates to explore quantum criticality both in and out of equilibrium. |
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N01.00040: Quantifying the advantage of Ghost imaging over Regular imaging Anjaneshwar Ganesan, Herman Batelaan Ghost imaging has been used in archaeology, bio-medicine, for seeing through turbid media, and promises X-ray imaging improvements, amongst many other applications. However, the advantage of ghost imaging over regular imaging is difficult to quantify. We searched for a simple example that can be quantified with basic statistics for the purpose of education. Using classical computational ghost imaging, we find that the signal-to-noise ratio for ghost imaging of a slit (the object) can exceed that of regular imaging with the same exposure of the slit when the detectors are sufficiently noisy. As a function of exposure the ghost imaging signal to noise starts to exceed that of regular imaging when the exposure is less than one photon per realization. It is also shown that the signal to noise of gated imaging under the same circumstances is similar to ghost imaging, while when the exposure exceeds one photon per realization, gated imaging approached regular imaging [1]. These result are obtained by numerical simulation and by theoretical analysis of the imaging techniques [2]. We propose an experiment to demonstrate this quantitative imaging advantage. |
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N01.00041: Towards correlated photon triplets using six-wave mixing in a cold atomic ensemble Yifan Li, Xi Jie Yeo, Christian Kurtsiefer While correlated photon pairs have been extensively investigated in various schemes, like spontaneous down-conversion in nonlinear medium and four-wave mixing from an atomic ensemble, the direct generation of correlated photon triplets is still challenging due to its weak nonlinearities and stringent phase matching requirements. Here, we explore a new approach for directly generating correlated photon triplets from a phase-matched parametric nonlinear process in a Rb87 cold atom ensemble. We propose a scheme to integrate electromagnetically-induced-transparency-based (EIT-based) photon pair generation in double-Λ energy levels with a four-wave mixing process in ladder energy levels. This results in a higher-order nonlinear parametric process referred to as six-wave mixing. The correlated photon triplets generated through this method have the potential to form a Greenberger-Horne-Zeilinger state of light, providing a distinct quantum source for investigating quantum entanglement and potential uses in three-party quantum communication protocols. Additionally, the narrow bandwidth of the generated photons, derived from the atomic natural linewidth, makes them appropriate for direct interaction with atoms. Therefore they have potential applications in quantum networks utilizing atom-based quantum repeaters. |
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N01.00042: Effects of neighboring transitions on electromagnetically induced absorption and transparency in Rb atoms with circular polarization of laser beams Zeeshan Ali Safdar Jadoon, Aisar Ul Hassan, Heung-Ryoul Noh, Jin-Tae Kim The effects of neighboring transitions on electromagnetically induced absorption (EIA) and electromagnetically induced transparency (EIT) in the D2 transition line in Rb atoms with respect to the parallel and orthogonal circular polarization configurations (σ+ - σ+ and σ+ - σ- ) of coupling and probe lasers have been investigated. For the same circular polarization configuration, spectra for the open transitions exhibit EIA or EIT due to neighboring effects depending on hyperfine energy splittings. For the orthogonal polarization configuration the dominance of closed D2 transition results in the observation of asymmetric and split EIA at all of transitions regardless of the openness or closing of the transitions. The spectra of 85Rb and 87Rb are analyzed by investigating the variation of the spectra of 85Rb with an artificial increase of the hyperfine splittings and accordingly with the decreasing of the neighboring effects. This leads to the difference in the absorption profiles of the two isotopes. |
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N01.00043: Transparency in two level systems using an optical frequency comb with sinusoidal phase modulation Aneesh Ramaswamy, Svetlana A Malinovskaya Transparency in atoms has been conventionally realized in three and higher-level systems through interference of probability amplitudes for multiple pathways between two states. We generalize this mechanism for creating transparency to two-level systems by using a frequency comb, a sinusoidally modulated phase-locked pulse train, to create a manifold of Floquet states. The presence of strong-field effects and multiple harmonics require us to explicitly calculate the energy shifts and decay rates in the Floquet basis. A Floquet-Lindblad master equation is then derived and used to calculate the field correlation necessary to find the spectral absorption. We use linear response theory and the time averaged correlation function to define a quasi-steady state absorption spectrum over one cycle of the pulse train. To solve for the dynamics, the Van-Vleck high frequency expansion was used to derive the effective Floquet Liouvillian and micromotion operators in a rotated frame. |
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N01.00044: Progress Towards Hyperentangled Photon Pair Generation Using Laser-Cooled Atoms Sunil Upadhyay, Adam T Black We present progress towards the generation of hyperentangled photon pairs in a cold atomic ensemble with an off-resonant pump. Relevant prior work[1,2] in cold trapped atoms has exploited an EIT-based lambda level schemes with an off-resonant write beam and a near-resonant read beam. Our proposed implementation uses a single pump field that is detuned by roughly half the ground state hyperfine splitting for both the read and the write process. This scheme is designed to produce photons entangled in both polarization and frequency, with the emitted frequencies differing by the rubidium ground-state hyperfine splitting. The experiment is carried out in a 3D magneto-optical trap of rubidium-87 atoms. We present the details of our level scheme, experimental setup, and progress towards the end goal of hyperentangled photon pairs generation. We additionally present studies of the dependence of correlated photon pair generation on pump beam spatial profile and pump detuning. |
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N01.00045: Investigation of Nonlinear Dispersion for Quantum Optics by Experiments with Cavity Polaritons in Polymers with Nonlinear Response Garrett D Compton, Mark G Kuzyk Parametric down conversion and four wave mixing are cornerstones of quantum optics that are independently well understood. However, a theory that properly handles nonlinear dispersion and its effects on many photon state evolution remains elusive. We develop a path toward a fully dispersive theory of nonlinear quantum optics, explore the consequences of simultaneously supporting parametric down conversion and four wave mixing with nonlinear dispersion, and discuss its applications to exotic photon state preparation, beam manipulation, and uses in metrology. Simulations of multiphoton state evolution are designed -- inspired by the work of Sipe et al. -- to include nonlinear dispersion ad hoc. We explore a variety of methods for including nonlinear dispersion and test their validity by replicating the simulation experimentally. Our experiments involve scattering cavity polaritons in stratified nonlinear polymers and microring resonators, and measuring correlations to determine the generation of time-frequency, path, and polarization entanglement for multiphoton systems beyond the biphoton regime. The experiments and simulation inform the development of a proper quantization of Maxwell's equations in nonlinear media. |
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N01.00046: Quantum optics with hot atomic vapors in various configurations Robert Loew, Harald Kuebler, Xiaoyu Cheng, Benyamin Shnirman, Annika Belz, Max Maeusezahl, Felix Moumtsilis, Moritz Seltenreich, Tilman Pfau Rubidium gases at room temperature can exhibit large optical non-linearities, even at the single photon level. To enhance these non-linearities one can either boost the interaction between the atoms or increase the atom-light coupling by photonic structures. We present optical non-linearities based on high lying Rydberg states exhibiting strong van-der Waals interactions, as well for low lying states via the light induced dipole-dipole interaction. The latter at rather high densities. By adding photonic waveguides, e.g. slot waveguides, ring resonators or photonic crystal cavities we can enhance the observed non-linearities. |
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N01.00047: Magnetic-field enhanced modulation transfer spectroscopy: theory and experiment Sanghyun Park, Jaeuk Baek, Geol Moon, Heung-Ryoul Noh We report a theoretical and experimental study on magnetic-field enhanced modulation transfer spectroscopy (MTS) for the 5S1/2 (F = 1)→5P3/2 (F′ = 0, 1, and 2) transitions of 87Rb atoms. The density matrix equations are solved numerically to obtain the MTS spectra and an excellent agreement is found between the experimental and calculated results. In particular, the enhancement of the MTS signal for the F = 1→F′ = 0 transition in the presence of the magnetic field is directly verified based on the comparison of the results calculated by neglecting with those calculated including the Zeeman coherences in the F = 1 ground state. The unexpected behaviors of the F = 1→F′ = 1 transition are also examined with two different configurations of probe-pump beam polarization. |
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N01.00048: Coherence effects in a spin-orbit mixed four-level molecular system coupled by three lasers Jianbing Qi We study the EIT and Autler-Townes effect in a spin-orbit mixed four-level molecular system coupled by three lasers. The spin-orbit mixed rovibrational levels are ubiquitous in molecules, which have been widely used in laser spectroscopy. The mixed levels’ characteristics depend on the degree of spin-orbit mixing. The mixing coefficient varies from case to case. The spin–orbit mixed states in such as diatomic molecules have been used as gateways to access some triplet transitions that are not possible in a lot of situations in laser spectroscopy of diatomic molecules. In this study, we show that the mixing coefficients of the singlet-triplet states can be modified using a laser to couple the mixed pair to an auxiliar level. We use density matrix equations for a spin-orbit mixed four-level molecular system to show that the EIT and Autler-Townes can be controlled by a coupling laser. |
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N01.00049: Efficient Measurement of Bi-photon OAM Spectrum with Stimulated Emission Tomography Yang Xu The technique of stimulated emission tomography (SET) provides excellent characterization of SPDC sources of bi-photon states since it increases the average number of photons detected by several orders of magnitude than the traditional coincidence counting method. In a SET experiment, the signal caused by the vacuum fluctuation in SPDC is replaced by a more intense prepared seed with the same mode properties, resulting in an amplification of the corresponding idler. Based on this idea, our experiment uses the difference frequency generation (DFG), a purely classical second-order nonlinear process, to measure the orbital angular momentum (OAM) spectrum of an entangled photon pair produced by a Type-I BBO SPDC crystal. We inject the CW seed beam at 780 nm with different Laguerre-Gauss modes together with a CW pump beam at 405nm into the Type-I BBO crystal and measure the Laguerre-Gauss mode distribution of the idler at 842nm. We observe an increase of 9 orders of magnitude in the idler production and good agreement with the theoretical prediction of the OAM spectrum. We expect that this experiment paves way for the efficient measurement of bi-photon wavefunctions produced by ultra-thin and weak SPDC sources and also the characterization of high-dimensional entangled photon pairs produced in SPDC. |
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N01.00050: Dephasing of ultracold cesium 80D5/2-Rydberg Electromagnetically Induced Transparency Jianming Zhao, Yuechun Jiao, Zhengyang Bai, Weibin Li We study Rydberg electromagnetically induced transparency (EIT) of a cascade three-level atom involving 80D5/2 state in a strong interaction regime employing a cesium ultracold cloud. In our experiment, a strong coupling laser couples 6P3/2 to 80D5/2 transition, while a weak probe, driving 6S1/2 to 6P3/2 transition, probes the coupling induced EIT signal. At the two-photon resonance, we observe that the EIT transmission decreases slowly with time, which is a signature of interaction induced metastability. The dephasing rate rOD is extracted with optical depth OD = rOD. We find that the optical depth linearly increases with time at onset for a fixed probe incident photon number Rin before saturation. The dephasing rate shows a nonlinear dependence on Rin. The dephasing mechanism is mainly attributed to the strong Rydberg interactions and simulated with density matrix equation. |
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N01.00051: INTENTAS - Second Quantization and Entanglement in Atom interferometry Samuel Böhringer, Richard Lopp, Wolfgang P Schleich Atom interferometry as a means for sensing has shown to be very successful in a wide range of applications. Recent efforts are focussing on reaching beyond the standard quantum limit where quantum correlations become relevant. For that purpose, we consider the fully second quantized dynamics of a Bose-Einstein condensate (BEC) interacting with the electromagnetic quantum field in gravity. We study the effects that noise and BEC self-interactions have on the evolution of entanglement as a resource for atom interferometry. In particular, we determine the importance of quantum fluctuations for the interferometer sequence. |
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N01.00052: Large Momentum Transfer via Shaking a 1D Optical Lattice Kendall J Mehling, Catie K LeDesma, Jieqiu Shao, Marco Nicotra, Murray J Holland, Dana Z Anderson Realization of a 1D matter-wave interferometer can be achieved by shaking the phase of an optical lattice to tailor the momentum states of ultracold atoms [1]. Producing analogs of the components of a conventional light-based interferometer- atomic beam splitter, mirror, and recombination pulse- allow for inertial sensing while the atoms are confined to the optical lattice. This approach is interesting, since the atoms can be supported against external forces and perturbations, and the system can be completely reconfigurable on-the-fly for a new design goal. Large momentum transfer between the atomic packets is desirable to effectively increase the enclosed area of the sensor during interrogation. We report on experimental results demonstrating rapid large momentum transfer to atoms via a shaken lattice. Reinforcement learning from experimental data for increased sensitivity of our matter-wave interferometer is also explored. |
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N01.00053: Continuous atomic-recoil lasing of strontium atoms in a high finesse ring cavity Zhijing Niu, Vera M Schäfer, Julia R Cline, Dylan J Young, Eric Song, James K Thompson We continuously load 88-strontium atoms into a high finesse ring cavity and observe coherent light emission over a large range of atom-cavity detuning. We identify four different lasing regimes, depending on the atom-cavity detuning and characterized in part by the dependency of the laser light’s frequency dependence on the applied laser cooling beams. While there are many open questions as to the exact mechanism of the observed lasing, we currently believe that the laser light arises from an inversion in momentum space that combines with atomic-recoil [1, 2] from absorption and emission of the laser cooling beams to produce optical gain. |
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N01.00054: Multi-loop and Multi-axis Operation of an Optically Guided Atom Interferometer Saurabh Pandey, Katarzyna Krzyzanowska, Ceren Uzun, Malcolm G Boshier Atom interferometers are poised to revolutionize inertial sensing and offers great precision for the tests of fundamental physics. Matter-waves can be held or manipulated for much longer times in a waveguide without increasing the size of the experiment. We report on the experimental realization of a large-area guided atom interferometer in an optical waveguide for rotation sensing. The sensitivity to rotation is directly proportional to the physical area enclosed by the atomic wave-packets. A larger loop area can either be achieved with a bigger single loop or letting the atoms go through each other multiple times before they are overlapped again, referred to as a multi-loop interferometer. A multi-loop configuration is desirable since the experiment volume can be kept small. Here, we present a three-loop interferometer with a total interrogation time of up to 367 ms and 8.6 sq. mm enclosed area. We show high contrast interference fringes for up to five Sagnac orbits in a smaller interferometer loop of total area 0.13 sq. mm. A unique feature of our scheme is that by moving a horizontally oriented waveguide in different planes, it is easily possible to sense rotation rates about multiple arbitrary axes. We describe interferometers with enclosed area in the horizontal and vertical plane and show similar interferometer contrast for the two cases. We will present our investigation of noise sources that degrade the interferometer performance. |
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N01.00055: Towards a test of quantum dissipation theory. Arjun K Uppath Mohanan, Marlon Weiss, raul puente, Herman Batelaan We report on the progress of an experiment to observe dissipation of kinetic energy of electron beam and quantum decoherence of the electron diffraction pattern as predicted by the Caldiera-Legget theory as a consequence of propagation over a conducting surface [1]. In a previous experiment, we found that an electron passing close to a conducting surface did not exhibit the level of decoherence one would expect [2]. One explanation is that the energy dissipation is smaller than predicted. The energy loss for charged particle with constant velocity travelling over a conductor have been modelled within classical electrodynamics by Boyer [3], and the predictions suggest an energy loss of ≈ 17 eV for a beam flying at a 20 micron height over a 1 cm long GaAs surface. Currently, we are measuring this with a retarding field analyzer (RFA). A relative resolution of 50 meV at an energy of 1600 keV is reached in a measuring time of 1 second. Using laser light to excite the conduction band of the GaAs surface, we can vary the resistivity of the GaAs surface. Additionally, the electron matter wave spatial coherence has been improved from 500 nm to exceed 1 μm, to improve the sensitivity to decoherence. |
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N01.00056: Hybrid atom—rare-earth ion interface for quantum networks Dahlia Ghoshal, Yuzhou Chai, Shankar G Menon, Noah Glachman, Shobhit Gupta, Matteo Pompili, Alexander Kolar, Alan M Dibos, Tian Zhong, Hannes Bernien To achieve a quantum network with both processing capabilities and robust storage, it is very appealing to leverage the complementary strengths of different quantum platforms. Coherently interfacing such platforms, however, can be challenging, as it requires wavelength and bandwidth matching, along with conversion to telecom wavelengths for long-distance entanglement distribution. As such, we propose a modular, hybrid quantum network architecture that has both programmability and multi-mode storage, and evades complex frequency conversion techniques by generating and storing entangled photons at telecom. We propose to use an atom array as our processor node, with integrated nanophotonic cavities to generate high-fidelity, high-rate entanglement between atoms and telecom photons. The photons can then be stored in a memory node consisting of a rare-earth ion-doped crystal that allows multiplexed storage. Here we present our results on identifying mode-matching conditions between rubidium atoms and an erbium-doped crystal, along with our experimental progress on coupling atoms to nanophotonics, generating single telecom photons via four-wave mixing in a hot rubidium ensemble, and preparing an atomic frequency comb memory in the crystal. |
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N01.00057: Exploring Quantum Networking Nodes for Neutral Atom Tweezer Arrays Elmer Guardado-Sanchez, Ivana Dimitrova, Brandon Grinkemeyer, Paloma Ocola, Danilo Shchepanovich, Eirini Mandopoulou, Vladan Vuletic, Mikhail D Lukin Rydberg atom arrays are promising candidate for quantum computation and information. Scaling up the platform beyond a few thousand qubits would require a modular approach. An integrated optical cavity could serve as a quantum networking node between distant quantum processors. Here we explore and compare two candidates for such a networking node: a nano-photonic crystal cavity (PCC) and a Fabry-Perot Fiber cavity (FPFC). With its small size, the PCC is compatible with Rydberg atoms ~ 200um away, however in its current design it can only host two atoms at the same time. The FPFC provides simultaneous strong coupling of many atoms in individual optical tweezers. |
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N01.00058: Progress Towards an Efficient Quantum Network with Rubidium Atoms Preston Huft, Akbar Safari, Christopher B Young, Jin Zhang, Eunji Oh, Ethan Lu, Arian M Noori, Mark Saffman We report on progress of an elementary quantum network between individual 87Rb atoms mediated by a photonic link. Each network node consists of a compact "plug-and-play" platform, which makes for a more readily deployable quantum communication testbed. In particular, by utilizing in-vacuum optics and optical fiber interfaces, the experiment footprint, including photon collection optics, is significantly reduced. In this first version, we implement a high-NA parabolic mirror for photon collection. In addition, we report on progress toward upgrading the system to use a near-concentric optical cavity for enhanced photon collection, which can be used to achieve atom-atom entanglement rates up to a few kHz, exceeding the current state of the art for neutral atoms and ions. This work was supported by NSF Award 2016136 for the QLCI center Hybrid Quantum Architectures and Networks, the U.S. Department of Energy Office of Science National Quantum Information Science Research Centers, and NSF Award 2228725. |
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N01.00059: Properties of generated photon-pairs via ladder-type configurations with different excited levels in cesium vapor cell HeeWoo Kim, Han Moon, Hansol Jeong, Jiho Park Single photon sources are foundation blocks in quantum information technology. There are so many candidates to create single photon sources such as atoms, nonlinear crystal, quantum dot, NV center etc. Among them, atoms can be used to create reproducible photonic system because the photons emitted by atoms have always same optical properties. In the quantum communication field, single photon sources having a narrow linewidth is needed to exploit many frequency channels and strong interaction between light and atom for atom-based quantum memory. One of the typical way to obtain the source is to use four-wave-mixing from a hot atomic ensemble. |
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N01.00060: Robust storage of topologically protected light in warm alkali vapor Benjamin Makias, Macbeth Julius, Reese Tyra, Jianqiao Li, Samir Bali We investigate the storage properties of light with different transverse electric field profiles in warm Rb vapor via electromagnetically induced transparency. We first store Gaussian and Laguerre-Gaussian (LG) beams, and study the evolution of the stored intensity profile. We show that even though the LG beam vortex remains topologically protected, the intensity profile of either beam is significantly broadened owing to atomic diffusion. Next, we produce a Bessel beam with an axicon and show that the non-diffracting intensity profile is relatively immune to atomic diffusion and is preserved during storage. |
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N01.00061: Optical Fractional Fourier Transform in the time-frequency domain based on quantum-memory. Bartosz Niewelt, Marcin Jastrzebski, Stanislaw Kurzyna, Jan Nowosielski, Wojciech Wasilewski, Mateusz Mazelanik, Michal Parniak Fractional Fourier Transform (FrFT) has a number of applications ranging from noise reduction to radar science and mode sorting of light. It has an intuitive meaning when we represent it as a rotation of chronocyclic Wigner function in time-frequency space. This can be achieved by applying specific time and frequency quadratic phases to the input signal by means of linear modulation of frequency and AC-Stark shift applied to light stored in the form of atomic coherence in the Gradient Echo Memory. Previous experiments show that quantum memories allow for versatile processing of quantum states of light including super-resolved spectroscopy and Fourier transform. We expand that idea and demonstrate implementation of FrFT in GEM. We benchmark the protocol by showing transformation of two-pulse "Schroedinger cat" states and Hermite-Gauss modes–eigenfunctions of FrFT--proving its possible application in mode sorting. We are the first to implement the FrFT in the optical time-frequency domain. This achievement opens up new avenues in optical signal processing. In particular, allowing tailored noise reduction protocols to be implemented purely in the optical domain. Our setup allows for manipulation of signals with bandwidth reaching 1 MHz and duration of 25 μs, allowing operation with ultra narrow band light compatible with atomic and optomechanical systems. |
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N01.00062: Quantum-memory-enabled optical spectrum to position converter for optimal spectro-temporal processing Jan Nowosielski, Mateusz Mazelanik, Michal Parniak Spectral analysis of optical pulses plays an essential role in classical and quantum optics. The ability to reconstruct the spectral profile of the light pulse or to perform an optimal measurement in the spectro-temporal domain is the basic tool in spectroscopy, classical and quantum communication, or even astronomy. In particular, the decomposition of the input signal into a set of orthogonal modes can be used to achieve ultimate precision in estimating a certain parameter of the light source, or in communication, where it can lead to an increase in the channel capacity, especially in the photon starved regime. One of the approaches to such mode sorting, allowing further processing is to perform the spectrum-to-position mapping. Here, we propose how to achieve such mapping using gradient echo quantum memory protocol (GEM). The memory utilizes a two-photon Raman transition to map signal pulses onto atomic coherence. During the write-in process, the atoms are placed in the magnetic field with a constant gradient allowing for frequency-to-position mapping along the propagation axis, thus different frequencies are absorbed into different parts of the atomic cloud. By utilizing the ac-Stark shift we can impose a spectral phase onto stored optical pulse, making different frequencies be emitted at different angles, thus separating them in the far field of the ensemble and allowing spectrally resolved detection using a simple camera. We numerically simulate the protocol and carefully discuss its experimental implementation and possible limitations. |
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N01.00063: Two-node Quantum Network using Silicon-Vacancy Centers in a Diamond Nanophotonic Cavity Yan-Cheng Wei, Can M Knaut, Yan Qi Huan, Pieter-Jan C Stas, Daniel R Assumpcao, Erik Knall, Aziza Suleymanzade, Maddie Sutula, David Levonian, Mihir K Bhaskar, Denis D Sukachev, Bartholomeus Machielse, Hongkun Park, Marko Loncar, Mikhail D Lukin Silicon-vacancy (SiV) centers integrated into diamond nanophotonic crystal cavities provide efficient spin-photon interfaces and constitute a promising platform for quantum networking. Recently, spin-photon gates, memory-enhanced quantum communication, efficient single-photon generation, and high-fidelity gates between the SiV electron and the auxiliary 29Si nuclear spin have been demonstrated, all using a single quantum network node. In this work, we report on experimental realization of a quantum link connecting two SiV-based quantum nodes spatially separated by 20 meters. Using this system we realize optically mediated entanglement between 2 remote SiVs, observing the Bell-pair entanglement fidelity exceeding 0.74. Ongoing efforts towards extending these techniques to enable long-distance quantum communication will be discussed. |
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N01.00064: Quantum Optics with Rare-Earth Doped Crystals Tatum Z Wilson, Ashwith Varadaraj Prabhu, Aniketh Balagonda, Elizabeth A Goldschmidt Rare-earth atoms in solids have many different qualities that make them good candidates for quantum memory including excellent coherence properties, large optical depth, and compatibility with integrated photonics. We use the large optical depth, long spin-state lifetime, and large ratio of inhomogeneous to homogeneous optical lifetime in Pr:YSO to spatially and spectrally tailor the Pr ensemble to implement dynamically reconfigurable, cavity-enhanced quantum memory. This is enabled via spectral hole burning to create Bragg gratings of spectral sub-populations of Pr atoms inside the crystal. We expect to be able to achieve high reflectivity in this regime, and also to implement active switching of the reflectors with an additional control field, by taking advantage of the level structure and other properties of Pr:YSO. This will enable the creation of dynamically tunable optical cavities, which can be coupled to additional Pr ensembles via additional spectral hole-burning processes enabling cavity enhanced quantum memory. We will present initial experimental progress investigating spectral hole-burning and theoretical calculations of expected reflectivity and switching properties with realistic parameters. |
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N01.00065: Quantum networking and vortex field experiments with Strontium ions Yuanheng Xie, Mika Chmielewski, Denton Wu, Norbert M Linke, Raphael Metz, Andrei Afanasev, Hao Wang Quantum networking across longer distances is an important avenue to scale quantum technology. In Strontium ions, there is a transition from the D3/2 to the P1/2 level at 1.1 um, a wavelength compatible with current fiber optic infrastructure and hence a good candidate for medium-distance quantum networking. This transition avoids the requirement of lossy photon conversion and direct transmission on the km scale of photons whose state is entangled with the ion is possible. We discuss the construction of a trapped Strontium ion experiment and give recent progress toward remote entanglement. The ion qubit states following our photon generation scheme are located at the D3/2 level and differ by Δmj=2. We suggest a method for generating the microwave vortex field, which carries an orbital angular momentum unit in addition to the photon spin unit, to drive this dipole-forbidden transition and present progress toward generating this field experimentally. |
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N01.00066: How subradiance and superradiance affect the g(2) correlations of photon emission in dense atom arrays Deepak Aditya Suresh, Francis J Robicheaux Superradiant and subradiant photon emission in dipole systems are typically associated with the g(2) correlation showing bunched and antibunched behavior respectively. While the lifetime of the state determines the recovery time of the g(2)(τ) after emission, we are interested in studying how the instantaneous two-photon correlation, or the g(2)(τ = 0), is quantitatively dependent on the lifetimes of the single and double excitation eigenmodes of the system. We explore this in dense collectively interacting dipole systems like sub-wavelength arrays in the low-intensity regime. We also demonstrate a situation where we can control the g(2)(τ = 0) of a mode using the phase difference with another interfering mode of light. This can be used to suppress or promote two-photon emission in a particular mode. This effect is particularly pronounced when one mode is subradiant and the other is superradiant. |
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N01.00067: Rymax-One: A neutral atom quantum processor to solve optimization problems Jonas Witzenrath, Niclas Luick, Benjamin Abeln, Daniel Adam, Kapil Goswami, Jonas Gutsche, Rick Mukherjee, Jens Nettersheim, Thomas Niederprüm, Dieter Jaksch, Henning Moritz, Herwig Ott, Peter Schmelcher, Klaus Sengstock, Artur Widera Quantum computers are set to advance various domains of science and technology due to their ability to efficiently solve computationally hard problems. Of particular interest are combinatorial optimization problems, whose solutions could provide the basis for optimal supply chains or efficient vehicle routing. Here, we present our project Rymax-One (www.rymax.one) - which aims at building a quantum processor using single 171Yb atoms trapped in arbitrary and reconfigurable arrays of optical tweezers. Thereby we not only enable hardware efficient encoding of optimization tasks, but also qubit realizations with long coherence times, Rydberg-mediated interactions and high-fidelity gate operations. Solving open questions on the details of the interaction and excitation scheme will yield the high fidelities that allow us to implement specialized quantum algorithms and tackle real-world problems. |
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N01.00068: Scattering theory of three-photon transport in chiral and bidirectional waveguide quantum electrodynamics (wQED) dingyu guo, Imran Mirza In this poster, we present the scattering thoery of three-photon propagation in one-directional (chiral) and bidirectional (non-chiral) waveguides that are coupled to a single two-level atom. The scattering thoery for single and two-photon cases in single-atom wQED have already been studied in the past (see for example, Phys. Rev. A 82, 063821 (2010)). In this work, we go beyond the two-photon case and discuss the possibility of three-photon bunching and anti-buncing in the context of strongly coupled wQED. Furthermore, we'll discuss the impact of atomic and waveguide losses on the three-photon transport. We expect the findings of our work to be useful in developing multi-photon quantum networking protocols. |
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N01.00069: Cavity QED with an atom tweezer array Jacquelyn Ho, Zhenjie Yan, Leon Lu, Dan M Stamper-Kurn Using an apparatus consisting of an optical cavity and a tweezer array of 87Rb atoms, we demonstrate mid-circuit cavity measurement and collective atomic scattering dynamics. We first present results on mid-circuit measurement in a neutral atom tweezer array. After preparing the tweezer array, we bring single atoms one at a time into a high-finesse optical cavity and perform either fluorescence- or transmission-based readout. To demonstrate mid-circuit measurement, we initialize a two-atom array and perform a microwave Ramsey sequence, with cavity measurement of the first atom in between pulses on the second atom, and show that the second atom’s coherence is unperturbed by the first atom measurement. We have extended our cavity readout capabilities to studying the collective scattering of multiple atoms in a cavity. Probing the atoms transversely to the cavity, we resolve the spatial structure of the cavity standing wave through the spatial dependence of atomic fluorescence as we scan the atom positions. We show constructive and destructive interference based on the relative positions of the atoms due to the phase of the cavity field at each atom. We also observe a collectively enhanced, super-linear scaling of the cavity photon number with the number of atoms in the cavity and study this behavior at probe detunings near and far from atomic resonance. Lastly, we discuss prospects for observing self-organized atom configurations due to the collective buildup of the cavity field by using cavity readout and fluorescence imaging to indicate atom localization. |
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N01.00070: Quantum correlations and multiatom excitation dynamics in an atom-waveguide interface Hsiang-Hua Jen The atom-waveguide interface mediates strong and long-range light-matter interactions through guided modes. In this one-dimensional system, we theoretically investigate the excitation localization of multiple atomic excitations under strong position disorder and collective subradiant decays of multiply excited atoms bound in space. Deep in the localization side, we obtain the time evolutions of quantum correlations via Kubo cumulant expansions, which arise initially and become finite and leveled afterward, overtaking those without disorder. In this interface, we also analyze their average density-density and modified third-order correlations, which can arise, and finite correlations can be sustained for long time. The time-evolved quantum correlations can give insights into the studies of few-body localization phenomenon and nonequilibrium dynamics in open quantum systems. |
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N01.00071: Coupling organic molecules to nanophotonic cavities to study collective effects Christian M Lange, Emma Daggett, Jonathan Hood Organic dye molecules have recently shown promise as sources of single photons. When cooled to liquid helium temperatures, dibenzoterrylene molecules in anthracene crystals exhibit lifetime-limited linewidths with a high probability of decay onto the zero-phonon line and minimal spectral wandering. Due to a charge transport phenomenon, laser light can be used to induce long-term frequency shifting on the order of the system's inhomogeneous broadening. This may allow for the efficient fine-tuning of frequencies to realize many-body resonant interactions in the solid state. We will present a strategy to couple multiple nearly resonant dibenzoterrylene molecules to a nanophotonic cavity to study collective effects. |
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N01.00072: Nonperturbative Treatment of Giant Atoms Using Chain Transformations David D Noachtar, Johannes Knörzer, Robert H Jonsson Giant atoms provide a fascinating example of how superconducting circuit implementations extend the range of quantum optical phenomena that can be experimentally studied. In particular, giant atoms permit the investigation of systems beyond the dipole approximation and exhibit pronounced non-Markovian effects. For example, polynomial decay, the possibility to design frequency-dependent coupling or the emergence of so-called oscillating bound states have been predicted for giant atoms. |
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N01.00073: Entanglement generation in a continuous-wave collective SU(4) bad-cavity laser Jarrod Reilly, Gage Harmon, John D Wilson, Simon B Jäger, Murray J Holland We theoretically investigate the collective dynamics of a dissipative SU(4) system consisting of two internal and two motional states. By unravelling the master equation into SU(4) quantum trajectory simulations, we show that the output light field exhibits properties similar to that of superradiant lasing. Entanglement between the two degrees of freedom allows the length of the collective atomic dipole to change with purely collective interactions, which is impossible in a system with only two states. We formulate an algorithm to trace out either degree of freedom, allowing us to calculate the macroscopic entanglement entropy that develops between the pseudospin (internal) and motional (external) degrees of freedom. We show this entanglement grows linearly with the number of atoms which is beyond what may be achieved with typical bipartite entanglement of two symmetric subsystems. Furthermore, we calculate the quantum Fisher information in steady-state in order to show how the multi-particle entanglement can be used to demonstrate beyond standard quantum limit metrology. |
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N01.00074: A Free Space Fabry-Perot Cavity with a Submicron Mode Waist Danial Shadmany, Anna Soper, Aishwarya Kumar, Matthew Jaffe, Lukas Palm, David Schuster, Jonathan Simon Programmable tweezer arrays and cavity QED are two platforms with distinct yet potentially complementary advantages for quantum information science. Interfacing these two systems has thus far been an outstanding challenge. We have developed a new type of Fabry-Perot resonator with tweezer-like properties – a so-called "small-waist" cavity. Utilizing a submicron-mode waist for efficient single atom trapping and high cooperativity, such a device promises to dramatically lower the finesse requirements (to as low as 60) in the field of cavity QED with strong coupling. This opens a new paradigm of optical elements integrated into such resonators and even out-of-vacuum cavities around glass cells. We overview the challenges of designing such a cavity from the perspective of stability and summarize recent experimental progress towards demonstrating strong-coupling in the small-waist regime. |
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N01.00075: Custom Cavity Fabrication Using Laser Ablation Ocean Zhou, Maurice Zeuner, Philipp Kunkel, Eric S Cooper, Jonathan R Jeffrey, Avikar Periwal, Jonathan Simon, Monika H Schleier-Smith In the past few decades, optical cavities have become a powerful tool to couple atoms over macroscopic distances via light, where a smaller waist of the light field enhances the coherent interactions required for quantum control. Generating a small waist, on the order of μm, combined with good stability of the resonator is enabled by an asymmetric design where the radius of curvature of one mirror is on the order of mm. Because such micromirrors are not commercially available, we employ a CO2 laser ablation setup to machine them, inspired by Refs. [1-2]. I will describe our setup, method of micromirror characterization, and planned use of such cavities. In the future, this setup will unlock additional custom mirror designs including arrays of micromirrors or aberration-corrected mirrors, in turn opening up more flexible cavity geometries such as degenerate cavities. |
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N01.00076: Coupling single atoms to a nanophotonic whispering-gallery-mode resonator Xinchao Zhou, Tzu-Han Chang, Hikaru Tamura, Sambit Banerjee, Chen-Lung Hung Interfacing cold atoms with nanoscale photonic structures promises stronger atom-light interactions and novel quantum functionalities via dispersion engineering, controlled photon propagation, topology, and chiral quantum transport, thus leading to new paradigms for quantum optics. In this poster, we demonstrate our system based on high quality silicon nitride microring resonators fabricated on a transparent membrane substrate, which is compatible with laser cooling and trapping of cold atoms. Single atoms are coupled to a nanophotonic whispering-gallery-mode resonator using two different methods: 1) an optical guiding technique that makes use of diffracted light from a nanophotonic waveguide to direct cold atoms to the evanescent region of the resonator, and 2) an optical conveyor-belt consisting of a moving optical lattice for controlled delivery of trapped atoms. We will also discuss prospects of cooling and loading cold atoms into a trap in the nearfield directly using a cavity pump field. Our demonstration paves the way to explore collective quantum optics and many-body physics by forming an organized atom–nanophotonic hybrid lattice and inducing tunable long-range atom-atom interactions with photons on a nanophotonic circuit. |
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N01.00077: Compact, configurable laser systems for deployable quantum applications Nate Phillips, Henry Timmers, Andrew Attar, Stefan Droste, Kurt Vogel, Kevin Knabe With the inherent precision, sensitivity, and traceability afforded by the atomic systems at their heart, advanced quantum sensors are poised to become integral parts of otherwise quotidian platforms. The full potential of state-of-the-art atomic clocks, magnetometers, electric field sensors, and inertial sensors will be realized when these technologies are advanced from their development in research labs to deployment in field applications on moving platforms. The size, weight, power, and cost (SWaP-C) of required laser systems must be reduced, and robustness to environmental perturbations must be improved, in order to meet the challenging requirements of deployed applications. Vescent Photonics, being a lead manufacturer of systems for deployable quantum, is actively developing modular laser and control systems that are not currently available on the market. Requirements for optical frequency combs, MOT and Raman lasers, and ultranarrow linewidth lasers will be reviewed for performance in both laboratory and harsh environments. Vescent has developed these systems for fielded next-generation quantum applications, such as cold atom microwave and optical atomic clocks that are intended as improvements to existing GPS timing systems. Requirements for frequency instability, optical power, relative intensity noise, and overall power consumption will be reviewed. Discussions on the impact that these laser systems would have on real-world quantum applications will be estimated. |
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N01.00078: QUANTUM INFORMATION SCIENCE
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N01.00079: Circuit complexity lower bounds for quantum enhanced metrology Richard R Allen, Angus Lowe Entangled quantum many-body states with high quantum Fisher information (QFI) enable the detection of an unknown signal with sensitivity beyond the Standard Quantum Limit (SQL). In this work, we present fundamental lower bounds on the quantum circuit complexity of n-qubit pure states enabling beyond-SQL sensitivity scaling, i.e., states for which the QFI is Ω(n1+δ) for some 0 < δ ≤ 1. Specifically, we establish three theorems proving lower bounds on the minimal circuit depth required to prepare quantum states with metrological advantage. Each addresses a different physical scenario concerning the locality of the sensing Hamiltonian and the connectivity of the quantum circuit architecture. For lattice Hamiltonians in D dimensions and geometrically local circuits, high QFI states have a circuit complexity of Ω(nδ/D). For Hamiltonians and circuits defined on hypergraphs of constant degree, we show a lower bound of Ω(log(n)). Finally, leveraging known techniques used to construct approximate ground state projectors for area laws, we prove an Ω(log(n)) lower bound for commuting Hamiltonians with constant degree interaction graph and arbitrary circuit connectivity. Our results constitute a “no free lunch” theorem for gaining a quantum advantage in metrology under physically reasonable assumptions. |
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N01.00080: Albert: a cloud-based quantum-sensor development platform for the masses Victor Colussi, Hannah North, Pranav Gokhale, Evan Salim, Noah Fitch Infleqtion’s cloud-accessible design platform “Albert” enables the development of quantum technologies based on ultracold atoms. The hardware is programmed by remote users, including control of dynamically reconfigurable optical fields that are applied to the atoms. This “painted potential” capability enables development of quantum sensors using a diverse set of tools, including Bragg and shaken-lattice interferometry and atomtronics. The platform includes also tutorials and simulations acting as a digital twin, enabling users ranging from novices to experienced researchers to explore potential applications before running them on hardware. We will introduce the Albert cloud platform and explore how users can leverage the system for developing their own sensors. |
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N01.00081: Entangled Quantum Antenna Andrew K Harter, Leonardo de Melo, Michael J Martin, Malcolm G Boshier We present a model for a quantum sensor which utilizes a uniform interaction between two-level atoms and takes advantage of global symmetries to achieve sensitivity scaling beyond the standard quantum limit (SQL). The state preparation steps require quantum optimal control techniques to reach the desired target states for sensing, but these trajectories can be computed classically, as they fully take place in the Dicke subspace, which grows linearly with the number of atoms. Furthermore, these trajectories automatically provide a means to measure the state and calculate the quantum phase in a robust way which is protected against measurement errors. We propose a proof-of-principle experiment utilizing a symmetric arrangement of a few Rydberg atoms excited from trapped 87RB which are strongly coupled by their dipole-dipole interaction. We also provide a discussion on how to this may be expanded to larger numbers of atoms where the uniform symmetry need not be exact. |
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N01.00082: Magnetometry and vector electrometry with atoms in circular Rydberg states Junwen Zou, Stephen D Hogan Atoms in Rydberg states can act as highly sensitive, and minimally invasive probes of static electric and magnetic fields [1,2]. To characterize and minimize these fields in cryogenic, high vacuum environments - such as those encountered in precision spectroscopy experiments with antihydrogen, or those required to measure the absolute neutrino mass by cyclotron radiation emission spectroscopy (CRES) following beta decay of atomic tritium [3,4] - it is desirable to implement magnetometers and electrometers with atoms that are already present in the apparatus to avoid contamination or detrimental effects of surface adsorption, e.g., the antihydrogen or tritium atoms themselves. Or to use species that are inert or cause minimal contamination, e.g., atomic hydrogen or helium. Here we demonstrate the measurement, and 1D mapping (spatial resolution of ±1 mm over a distance of 40 mm) of static magnetic fields, and the minimization, and characterization of residual uncancelled static electric fields by a combination of microwave Ramsey spectroscopy of transitions between circular Rydberg states, and low-l Rydberg states in helium. Magnetic fields of 1.4 - 1.6 mT were measured to a relative precision of ±100 nT in a measurement time of 1 μs, with an absolute precision limited by Doppler shifts to ~1 μT. Residual uncancelled electric fields were determined in the x, y and z dimensions in the apparatus to an absolute precision of ±600 μV/cm. These results pave the way for atoms in circular Rydberg states to be used for electric and magnetic field mapping in experiments to measure the neutrino mass by CRES. |
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N01.00083: Progress toward NMR of single nuclei using single atoms in solid neon David M Lancaster, Ugne Dargyte, Jonathan D Weinstein Rubidium atoms trapped in a solid neon matrix have demonstrated long electron-spin coherence times as well as the ability to optically control and read out the Rb atom's spin state. Ensembles of implanted atoms have been used to detect the presence of Ne-21 nuclei via NMR spectroscopy. This poster will show results from measurements of ensembles of Rb atoms in solid Ne, as well as preliminary results of detecting the spin state of single Rb atoms. |
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N01.00084: A millimeter-wave atomic receiver: sensitivity and selectivity Remy Legaie, Georg A Raithel, David A Anderson Rydberg quantum sensors are sensitive to radio-frequency fields across an ultra-wide frequency range spanning megahertz to terahertz electromagnetic waves resonant with Rydberg atom dipole transitions. The sensitivity in Rydberg quantum sensors at millimeter-wave frequencies is generally limited by a drop of the electric-dipole matrix elements (that scale as n^2) between low-lying Rydberg states and optical frequency and amplitude noise present in the quantum state readout. We demonstrate a millimeter-wave heterodyne atomic receiver using continuous-wave lasers locked to an optical frequency comb. We show first sensitivity measurements at a frequency of f = 95.992512 GHz (W-band) signal field and characterize the sensor selectivity to resonant millimeter-wave fields, obtaining signal rejection ratios for channel widths Delta f/f = 10^{-4}, 10^{-5} and 10^{-6}. Our work represents an important advance towards future studies and applications of atomic receiver science and technology and in weak millimeter-wave signal detection. |
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N01.00085: Moving towards a compact and transportable quantum inertial sensor using an opto-mechanical resonator Ashwin Rajagopalan, Ernst Rasel, Sven Abend, Dennis Schlippert Atom interferometers measuring acceleration with respect to its retro-reflecting inertial reference mirror are also extremely sensitive to ambient ground vibrations. The effects of vibrational noise can be mitigated with the use of a vibration isolation platform, but it is not conducive for miniaturizing the atom interferometer sensor head. Classical commercial accelerometers can also be used to measure and correct for vibrations, although compatibility is a limitation. As a solution to these problems, we are developing compact and compatible opto-mechanical accelerometers in order to achieve maximum suppression of vibrational noise without posing a dimensional constrain. We have demonstrated efficient hybridization with such an opto-mechanical resonator [1] which enables a level of acceleration sensitivity 8 times lower than the limit due to ambient ground vibrations without any vibration isolation. Future versions are being designed to possess higher intrinsic sensitivities for integration in atom interferometers with larger interrogation times. We are also working towards direct integration onto atom chips with ultra-high vacuum compatible versions. |
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N01.00086: All In One Quantum Diamond Microscope for Rapid Sample Characterization. Connor Roncaioli, Connor A Hart, Donald P. Fahey Nitrogen Vacancy (NV) defects in diamond host optically pumpable spin-1 states with long coherence times which are ideal for room temperature magnetometry. Samples can be engineered to have part-per-million NV density, creating robust, portable, vectorized magnetic sensors with high spatial resolution. We present an all-in-one apparatus which can simultaneously measure NV ensemble quantum coherence properties across mm-scale regions, as well as classical properties such as diamond substrate and active layer strain and NV charge state, allowing us to characterize NV diamond samples rapidly for magnetometry applications. |
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N01.00087: Rydberg Atom-based Sensors: Two-photon and Three-photon readout schemes Matthias Schmidt, Stephanie Bohaichuk, Chang Liu, Vijin Venu, Florian Christaller, Harald Kübler, James P Shaffer We present intuitive explanations of atom-based RF electric-field sensors based on Rydberg states in hot vapors. There are two distinct strategies to detect the electric field strength of the RF wave, namely the Autler-Townes limit, where the splitting of the dressed states is proportional to the incident RF electric field strength and the amplitude regime, where we determine the electric field by measuring the change in transmission of a probe laser in the presence of the RF electromagnetic field. We present theoretical calculations for the amplitude regime, using a two-photon excitation scheme, extensible to other read-out schemes, that shows how the scattering of the probed transition changes in the presence of the RF electromagnetic field. We find an analytic expression in the thermal limit with finite wave vector mismatch that yields an accurate approximation and provides theoretical insight into the physics of the sensor. Furthermore, we present results on a three-photon excitation scheme, with which residual Doppler broadening is suppressed. The three-photon scheme enables a spectral resolution comparable to the Rydberg state decay rate, the spectral bandwith limitation, effectively eliminating the limitation of residual Doppler shifts. We present recent measurements on the sensitivity. The extension of the two-photon theory to the three-photon experiment is addressed. |
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N01.00088: Sensitivity Measurements of UHF-Band Electric Fields with Electromagnetically-Induced Transparency and Heterodyne Detection Michael A Viray, Baran N Kayim, Jasmine Jones, Robert Wyllie, Brian C Sawyer, Samuel Berweger, Nikunjkumar Prajapati, Alexandra B Artusio-Glimpse, Andrew P Rotunno, Roger C Brown, Christopher L Holloway, Matthew T Simons, Eric Imhof, Steven R Jefferts, Jonathan M Wheeler, Thad G Walker We present results on Rydberg atom-based electric field sensing in the ultra high frequency (UHF) radio band. Like other frequency bands of radio and microwave radiation, UHF signals can be detected with atom-based field sensing by resonantly driving Rydberg-Rydberg transitions and observing the atomic response. In this work, we utilize a three-photon excitation scheme to excite rubidium-87 atoms in a vapor cell to Rydberg F-states. At these states, UHF signals can resonantly drive nF → nG transitions and perturb the absorption coefficient of the atomic vapor. The magnitude of the UHF signals is then determined by monitoring the absorption of the probe laser through the vapor cell. We measure applied signal fields with heterodyne detection, which allows for enhanced detection of weak fields. The sensor's resonant frequency and sensitivity are a function of the principal quantum number n of the nF → nG transition; for n = 45, we report a sensitivity of 3.9 μV/(m√Hz) at a signal frequency of 899 MHz. |
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N01.00089: Engineering an Array of Squeezed Spin States by Coherent Rydberg Dressing Jacob A Hines, Shankari V Rajagopal, Gabriel L Moreau, Michael Wahrman, Neomi A Lewis, Nazli U Koyluoglu, Monika H Schleier-Smith Squeezed spin states are entangled states that enable a reduced quantum uncertainty in precision measurements of time and electromagnetic fields. A number of applications, from field imaging to clock comparisons for tests of fundamental physics, require generating squeezing in multiple spatially separated ensembles. We engineer an array of spin-squeezed ensembles of cesium atoms by off-resonantly coupling to a Rydberg state, a technique known as Rydberg dressing. We discuss optimization of our experimental sequence, consisting of optical pulses for squeezing and microwave pulses for dynamical decoupling, to enhance the coherence of our interactions and minimize atom loss. We observe squeezing across multiple ensembles, each containing hundreds of atoms, with the strength of squeezing controlled by the local intensity of the dressing light. Our work demonstrates the capacity of local interactions to produce squeezed states and paves the way for applications including atomic tweezer clocks. |
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N01.00090: Towards Spin Squeezing in a Two-dimensional Ensemble of Nitrogen-Vacancy Centers Zilin Wang, Weijie Wu, Emily Davis, Bingtian Ye, Simon Meynell, Lillian Hughes, Francisco Machado, Sobrina Chern, Ania Jayich, Norman Y Yao Using entangled states to enhance quantum metrology represents an exciting near-term application for NISQ hardware. In particular, spin-squeezed states have been demonstrated to enhance phase resolution beyond the standard quantum limit. Generating squeezed states via unitary evolution traditionally requires all-to-all Ising interactions, whereas native interactions on a variety of platforms are typically local. Recently, squeezing via a broader class of power-law XXZ Hamiltonians has been explored numerically, motivating experimental investigations of squeezing with dipolar interactions. Our platform consists of a two-dimensional spin ensemble of nitrogen vacancy (NV) centers in a [111]-cut diamond. We work with the NV centers quantized along the out-of-plane direction, which evolves freely under the intrinsic dipole-dipole interaction to generate the spin squeezed states . Reduction of the spin projection noise can be probed via relaxometry of another group of NV centers, allowing a diagnosis of squeezing without sub-shot-noise detection resolution. Because the angular average of the dipolar interaction is zero in three dimensions, our two-dimensional sample uniquely enables squeezing via native interactions in a solid-state spin ensemble. |
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N01.00091: Experimental demonstration of super-Heisenberg quantum metrology with indefinite gate order Peng Yin, Xiaobin Zhao, Yuxiang Yang, Yu Guo, Wen-Hao Zhang, Gong-Chu Li, Yong-Jian Han, Bi-Heng Liu, Jin-Shi Xu, Giulio Chiribella, Geng Chen, Chuan-Feng Li, Guang-Can Guo The Heisenberg precision limit, a 1/N scaling for ensemble measurement with N independent elements, is widely believed to represent the ultimate precision limit of quantum metrology. Several proposals have challenged this belief in the past, for example using non-linear interactions among the probes. Nevertheless, the Heisenberg limit is found to stand firm and remain observed by these proposals with respect to relevant resources, such as the total energy of the probes. Here in this work, we demonstrate a quantum metrology protocol surpassing the Heisenberg limit by probing two groups of independent processes in a superposition of distinct alternative orders. With each process creating a phase space displacement, our setup achieves the super-Heisenberg limit 1/N^2 in the estimation of a geometric phase associated with the two sets of N displacements. In contrast to previous studies, our results only require a single photon probe whose initial energy is independent of N, and are shown to outperform every reported setup where the displacements are probed in a definite order. Our experiment demonstrates indefinite causal order interferometry in a continuous-variable system and opens up experimental investigations of quantum metrology setups boosted by indefinite causal order. |
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N01.00092: Exact Quantum Algorithms for Quantum Phase Recognition: Renormalization Group and Error Correction Ethan A Lake, shankar balasubramanian, Soonwon Choi We explore the relationship between renormalization group (RG) flow and error correction by constructing quantum algorithms that exactly recognize 1D symmetry-protected topological (SPT) phases protected by finite internal Abelian symmetries. For each SPT phase, our algorithm runs a quantum circuit which emulates RG flow: an arbitrary input ground state wavefunction in the phase is mapped to a unique minimally-entangled reference state, thereby allowing for efficient phase identification. This construction is enabled by viewing a generic input state in the phase as a collection of coherent `errors' applied to the reference state, and engineering a quantum circuit to efficiently detect and correct such errors. Importantly, the error correction threshold is proven to coincide exactly with the phase boundary. We discuss the implications of our results in the context of condensed matter physics, machine learning, and near-term quantum algorithms. |
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N01.00093: Scalable Protocols for Characterization of Correlated non-Markovian Noise in Trapped-Ion Quantum Processors Omid Khosravani egin{document} |
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N01.00094: Error budget investigation of an ion-trap based quantumcomputer Ludwig Krinner, Timko Dubielzig, Nicolas Pulido-Mateo, Hardik Mendpara, Markus C Duwe, Christian Ospelkaus Trapped ions are a promising platform for reaching quantum-computation at or beyond fault tolerance level. The long qubit coherence time and low gate error-rates demonstrate important steps towards this goal~[1]. Our group has recently demonstrated low error rate entanglement operations based on near-field oscillating magnetic field gradients~[2][3]. We give a detailed road-map towards pushing the error in the two-qubit gate operations towards or below the $10^{-4}$ per gate level by means of a detailed numerical study of the computation register and associated physical processes. |
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N01.00095: Adaptive randomized Pauli measurement Wonjun Lee Quantum simulators and computers are powerful platforms for investigating the physics of strongly-correlated quantum systems. To fully utilize their potential, however, one needs to efficiently extract physically relevant features from the simulated many-body states. Here, we propose such an adaptive randomized measurement protocol. Instead of performing fully randomized measurements, our approach adaptively changes its measurement basis at each step, based on Bayesian inference of prior measurement outcomes. We demonstrate the utility of our protocol by applying it to spontaneously symmetry breaking and symmetry-protected topological (SPT) phases, from which we successfully extract the classifying observables such as order parameters and SPT invariants, and to learning stabilizer states. These establish a practical, physics-oriented protocol, which can potentially lead to new scientific discoveries in near-term quantum simulations of strongly-correlated many-body systems. |
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N01.00096: Ancilla Assisted Shadow Tomography: Measuring Arbitrary Physical Properties in Analog Quantum Simulation Daniel Mark, Minh C Tran, Wen Wei Ho, Soonwon Choi We propose and analyze a scalable protocol to efficiently extract many physical properties of states prepared in analog quantum simulators. Our protocol leverages the ergodic nature of generic quantum dynamics. The protocol does not require sophisticated controls and can be generically implemented in today's analog quantum simulation platforms. Our protocol involves introducing ancillary degrees of freedom in a predetermined state to a system of interest, quenching the joint system under Hamiltonian dynamics native to the particular experimental platform, and then measuring globally in a single, fixed basis. We show that arbitrary information of the original quantum state is contained within such measurement data, and can be extracted using a classical data-processing procedure. We numerically demonstrate our approach with a number of practical examples, measuring quantities such as the entanglement entropy, many-body Chern number, and superconducting orders, only assuming existing technological capabilities. Our protocol excitingly promises to overcome limited controllability and, thus, enhance the versatility and utility of near-term quantum technologies. |
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N01.00097: DEGENERATE GASES AND MANY-BODY PHYSICS
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N01.00098: Probing non-equilibrium quench dynamics in a homogeneous two-dimensional Bose gas Sambit Banerjee, Hikaru Tamura, Cheng-An Chen, Chen-Lung Hung Two-dimensional (2D) quantum gases in an arbitrarily painted box potential offers a versatile platform for studying non-equilibrium dynamics which may be difficult to realize in samples loaded into conventional harmonic traps. In this poster, we present our investigations of several quench-induced dynamics under different scenarios: 1) fragmentation and formation of matter-wave Townes solitons under attractive interactions, and 2) observation of spontaneous defect formation in a 2D superfluid. Our studies of 2D Townes solitons unveil a set of scale-invariant and universal scaling behaviors at negative atomic interactions. The observed defect formation in a superfluid results from atomic interaction with a quenched circular box under repulsive interaction strengths. We report observation of ring-shaped dark solitons emerging from the edge, and its evolution under a transverse (snaking) instability at discrete azimuthal angles. This results in a patterned formation of vortex dipole necklace. Furthermore, through in situ density noise measurements, we present direct characterization of coherence and even quantum entanglement within box-trapped quantum gases following interaction quenches. |
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N01.00099: Emergent s-wave interactions in low-dimensional systems of a spin-polarized Fermi gas Colin J Dale, Kenneth G Jackson, Jeff Maki, Kevin G. S. Xie, Ben A Olsen, Denise J. M. Ahmed-Braun, Shizhong Zhang, Joseph H Thywissen Ultracold atom experiments in low dimensions often work in regimes where motional ground states are prepared in strongly confined degrees of freedom. In this work, we study interactions near a p-wave Feshbach resonance in a spin-polarized gas of fermionic Potassium-40. One- and two-dimensional optical lattices confine our gas, creating quasi-two- and quasi-one-dimensional systems, respectively. The crucial new element of our investigations is the activation of orbital degrees of freedom by allowing population in multiple bands of the confinement lattice. We find that atoms orbitally excited in the strongly confined directions scatter with emergent s-wave character with atoms in the ground orbital state. Scattering resonances occur at energies displaced by the orbital excited-state energy from the underlying p-wave resonance energy. The resonances are characterized with radio-frequency (rf) dimer association measurements and rf spectroscopy. A multi-band model of scattering is used to predict dimer energies for each resonance. Correlations in the gas are related to the high-frequency tail of rf spectroscopy, and match the predicted scaling for s- and p-wave resonances. Our investigations of emergent s-wave scattering in multiple low-dimensional geometries may provide new routes for exploring universal many-body phenomena. |
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N01.00100: Solitary waves in trapped quantum droplets Simeon I Mistakidis, Garyfallia Katsimiga, Georgios Koutsokostas, Dimitri Frantzeskakis, Ricardo Carretero-Gonzalez, Panayotis Kevrekidis We unravel the existence and stability properties of dark soliton solutions as they extend from the regime of trapped quantum droplets towards the Thomas-Fermi limit in homonuclear symmetric Bose mixtures. Leveraging a phase-plane analysis, we identify the regimes of existence of different types of quantum droplets and subsequently examine the possibility of black and gray solitons and kink-type structures in this system. Moreover, we employ the Landau dynamics approach to extract an analytical estimate of the oscillation frequency of a single dark soliton in a trapped droplet. Within the extended Gross-Pitaevskii framework, we find that the single soliton immersed in a droplet is stable, while multisoliton configurations exhibit parametric windows of oscillatory instabilities. Our results pave the way for studying dynamical features of nonlinear multisoliton excitations in a droplet environment in contemporary experimental settings. |
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N01.00101: Bragg spectroscopy of 1D fermions with attractive interactions Ruwan Senaratne, Aashish Kafle, Danyel Cavazos-Cavazos, Randall G Hulet Spin-1/2 fermions are expected to pair in one dimension for any strength of attractive interactions. Evidence of pairing of fermionic neutral atoms in quasi-1D traps has previously been obtained using RF spectroscopy to directly probe the binding energy of the pairs [1] but can also be obtained by performing Bragg spectroscopy to measure the speeds of the (charge) density waves and the spin density waves. These speeds are equal in the ideal gas, but for weak attractive interactions, the spin-mode velocity increases while the charge-mode velocity decreases. This is the opposite of the classic hierarchy observed in Tomonaga-Luttinger liquids with repulsive interactions [2]. For strong attractive interactions, the speed of the charge-mode halves, indicating tightly bound pairs, and the spin-mode becomes gapped. We prepare spin-balanced gases of 6Li in quasi-1D traps, formed by a 2D optical lattice, and perform Bragg spectroscopy, probing either the charge or spin mode in the regime of weak attractive interactions. We observe an inversion of the classic spin-charge velocity hierarchy in this regime, confirming expectations from exact Bethe ansatz solutions for the homogeneous gas at zero temperature. This observation, near a zero-crossing in the 3D s-wave scattering length on the BEC-side of a Feshbach resonance, indicates the formation of confinement-induced background dimers [3], which are distinct from the previously observed confinement-induced Feshbach dimers. We also observe charge-mode Bragg spectra in the strongly attractive regime consistent with tightly bound Feshbach dimers. |
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N01.00102: Induced attractive and repulsive interactions between two distinguishable Bose polarons Friethjof Theel, Simeon I Mistakidis We study the impact of induced correlations and quasiparticle properties by immersing two distinguishable impurities in a harmonically trapped bosonic medium. It is found that when the impurities couple both either repulsively or attractively to their host, the latter mediates a two-body correlated behavior between them. In the reverse case, namely the impurities interact oppositely with the host, they feature anti-bunching. Monitoring the impurities relative distance and constructing an effective two-body model to be compared with the full many-body calculations, we are able to associate the induced (anti-) correlated behavior of the impurities with the presence of repulsive (attractive) induced interactions. Furthermore, we capture the formation of a bipolaron and trimer state in the strongly attractive regime, where the latter consists of two impurities and a medium atom. Our results open the way for controlling polaron induced correlations and creating relevant bound states. |
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N01.00103: Quasi-1D Spin-imbalance Fermi gas and a new Li quantum gas machine Jimmy Yeh, Jacob A Fry, Bhagwan D Singh, Randall G Hulet Quantum simulation of ultracold atomic Fermi gases provides an ideal platform to study the behavior of electrons in solid-state systems. One particular interest is the study of the finite momentum Cooper pair, also known as the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state. The FFLO phase is believed to occupy larger phase space in low dimensions, whereas it is more robust against quantum and thermal fluctuations in high dimensions [1][2]. Therefore, our spin-polarized gas is prepared in the quasi-1d regime by tuning the inter-tube tunneling rate of a 2D optical lattice and the interaction strength via a magnetic Feshbach resonance. In this poster, we review our methods and progress toward the direct observation of the domain walls, where the periodicity of the domain walls is a consequence of an LO-type order parameters and finite momentum pairing. |
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N01.00104: Rapidity and momentum distributions of 1D dipolar quantum gases Zhendong Zhang, Kuan-Yu Li, Yicheng Zhang, Kangning Yang, Kuan-Yu Lin, Sarang Gopalakrishnan, Marcos Rigol, Benjamin L Lev We explore the effect of tunable integrability breaking dipole-dipole interactions in the equilibrium states of highly magnetic 1D Bose gases of dysprosium at low temperatures, using measurements of rapidity and momentum distributions. In the strongly correlated Tonks-Girardeau regime, those distributions are nearly unaffected by the dipolar interactions. This suggests that bare quasiparticles can be used to characterize that regime. By contrast, decreasing the strength of the contact interactions results in higher 1D densities and stronger dipolar interactions, which produce significant changes of the rapidity and momentum distributions. This indicates that the dressing of the quasiparticles needs to be accounted for to characterize that regime. We show that modeling the system as an array of 1D gases with only contact interactions, dressed with the contribution of the short-range part of the dipolar interactions, captures the main experimental observations. |
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N01.00105: Exploring quasicrystal dynamics with degenerate strontium Anna R Dardia, Toshihiko Shimasaki, Yifei Bai, Peter Dotti, Jared E Pagett, Esat Kondakci, David M Weld Ultracold atoms in 1D bichromatic optical lattices realize the Aubry-André-Harper model, enabling the dynamical study of localization, pseudo-disorder, and quasicrystals. We report recent results on the coherent control of Aubry-André localization by phasonic modulation, and the experimental realization of the kicked Aubry-André-Harper (kAAH) model via periodic pulsing of the secondary lattice. In the latter case, we explore the global phase diagram of the kAAH model using a Floquet apodization technique. We discuss extensions to these studies, including the implementation of time-reversed evolution in the Aubry-Andre model and the investigation of the interplay between disorder-induced localization and dynamic localization. Separately, we discuss planned upgrades and future directions including a scheme for phase-stabilized 2D optical lattices with tunable geometry. |
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N01.00106: Instabilities and the onset of Turbulence in Bose-Einstein Condensates Edward Eskew, Michael M Forbes, Peter W Engels, Maren E Mossman The mechanism behind pulsar glitches - sudden unexplained increases in the pulsation rate despite continuous loss of angular momentum - is not well understood, but likely related to hydrodynamic instabilities that arise from underlying quantum turbulence in the nuclear superfluids within the star. I will focus on simulations at the threshold of instability and at the onset of turbulence, such as experimentally accessible Rayleigh-Taylor instabilities. |
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N01.00107: Rarefaction waves and channel turbulence in a superfluid dam-breaking experiment Judith Gonzalez Sorribes, Peter W Engels, Maren E Mossman The development of ultracold atomic tabletop experiments has given unprecedented access to investigations into superfluid hydrodynamics. A canonical problem of hydrodynamics is the dam-break problem, where a channel is separated into a full and an empty (or partially filled) section, and the separating barrier is abruptly removed. In our previous work, we have experimentally realized the development of dispersive shock waves in the presence of superfluid-superfluid counterflow in a quasi-1D channel, as well as viscous shock waves preceding a driven optical piston. Here, we expand this work by investigating the dam-breaking problem in an elongated Rb-87 Bose-Einstein condensate to study rarefaction waves with both "dry bed" and "wet bed" initial conditions. This poster will describe our experimental method using a 1D sweeping repulsive potential and our experimental results, indicating rich turbulent regions when even a small number of atoms have been introduced, e.g. the "wet bed" scenario. This work provides a new pathway towards the study of superfluid channel turbulence, an outstanding problem in superfluid hydrodynamics. |
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N01.00108: Nonlinear Sound Waves in Ultracold Fermi Fluids Songtao Huang, Yunpeng Ji, Grant L Schumacher, Gabriel T Assumpcao, Jianyi Chen, Nir Navon Studies of sound propagation have been fruitful in revealing various thermodynamic and transport properties of its medium, such as compressibility and diffusivity. Much of the activity has focused on the linear-response regime. Here we report the excitation and observation of nonlinear sound waves in degenerate Fermi gases. We apply an oscillating spatially homogeneous force to a uniform spin-balanced Fermi gas and measure the displacement of the center-of-mass (CoM) versus the driving frequency. We observe different signatures of the emergence of nonlinear acoustic response in both the weakly and strongly interacting Fermi gases. |
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N01.00109: Replica symmetry breaking in multimode cavity QED Henry S Hunt, Brendan Marsh, Ronen Kroeze, David Atri Schuller, Alexander Bourzutschky, Henry S Hunt, Surya Ganguli, Sarang Gopalakrishnan, Jonathan Keeling, Benjamin L Lev We numerically demonstrate that an interacting atomic spin system coupled via a multimode optical cavity can enter a spin glass regime with replica symmetry breaking (RSB). Multimode optical cavities support many degenerate transverse modes that can mediate all-to-all sign-changing spin interactions. Such a system realizes an approximate, disordered Ising model with a transverse field. We simulate the pumping of the system through the Ising transition and study individual replicas as quantum trajectories monitored under continuous measurement. A Parisi-like overlap distribution is found from the RSB that emerges via dissipation. |
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N01.00110: Spontaneous defect formation and causality effect in inhomogeneous Bose gases Myeonghyeon Kim, Tenzin Rabga, Yangheon Lee, Junhong Goo, Dalmin Bae, Yong-il Shin Topological defects may be spontaneously created during a phase transition involving symmetry breaking. In a system with density inhomogeneity, the critical point is reached locally then the front of the transition spreads through the system with a finite velocity. The formation of defects can be suppressed if the spread of the transition front is slower than the spread of ordered phase information. We experimentally investigate this suppression of defect formation in an inhomogeneous, trapped Bose gas that is rapidly cooled into a superfluid phase. The results indicate that spontaneous defect production is more suppressed in the outer region of the sample where the atomic density gradient is higher. Furthermore, the power-law scaling of the local defect density with respect to the cooling time is enhanced in the outer region. |
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N01.00111: Exploring the physics of polaritons with ultracold matter waves Youngshin Kim, Alfonso Lanuza, Hongyi Huang, Loc T Ngo, Muxi Liu, Dominik Schneble Ultracold atoms in state-selective optical lattices offer a unique platform for the study of quantum optical phenomena in which atoms and light switch their roles of emitters and radiation [1]. Our group has recently extended this platform to allow for the study of polaritonic condensed-matter phenomena described by a combination of the Bose-Hubbard and the Weisskopf-Wigner models. We review our group’s recent experimental and theoretical studies [2,3] of the formation of matter-wave polaritons, and report new results of collective radiative decay and emission dynamics from an excitonic phase. Ongoing efforts and future directions will be discussed. |
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N01.00112: Design of a multi-region optical trap for non-equilibrium Fermi gases Maximillian Mrozek-McCourt, Christopher Angyal, Dadbeh Shaddel, Hannah Clark, Amondo Lemmon, Daniel Huffman, Vivek Chakrabhavi, Ariel T Sommer Quantum degenerate Fermi gases allow exploration of transport and non-equilibrium dynamics in strongly correlated systems. A multi-region optical trap gives access to non-equilibrium conditions in which separate regions of the trap are initialized in different thermodynamic states. We present the design and characterization of an optical system for implementing a multi-region optical trap. Intersecting a ring-shaped beam with four light sheets creates a three-region trap, which provides a platform for measurements of spin transport in homogeneous gases and across normal-superfluid interfaces. The light sheets form programmable barriers between the trap regions. We generate a ring-shaped beam using an axicon and light sheets using a digital micromirror device (DMD). We discuss the optical resolution of the trapping light, and the use of half-toning to improve the uniformity of the light sheets. In addition, we describe the preparation of a gas of cold lithium-6 atoms in an optical dipole trap for transfer into the multi-region trap. |
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N01.00113: Superfluid shear layer turbulence realised through machine learning optimisation Simeon Simjanovski, Tyler W Neely, Guillaume Gauthier, Matthew J Davis, Halina Rubinsztein-Dunlop In recent years, machine learning has emerged as a powerful technique for optimising BEC experiments. Our experimental system consists of a 2D BEC confined using a potential derived from a digital micromirror device, permitting high resolution dynamic control of the condensate [1]. Using a ring-shaped configuration, we optimise the generation of counter-rotating persistent currents through machine-learner control of a stirring barrier. We find that the learner optimises stirring under several different constraints, including maximising winding number or minimising stirring time. |
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N01.00114: Simulating the Temperature-Dependent Absorbing-State Phase Transition in a Rydberg Many-Body Facilitated Gas using Neural Networks Simon Ohler, Daniel Brady, Winfried Ripken, Michael Fleischhauer, Johannes S Otterbach We investigate the many-body dynamics of driven dissipative Rydberg gases in the facilitation regime, where the emergence of self-organized criticality (SOC) has been experimentally observed [Helmrich et al., Nature 577 (2020)]. Using a graph neural network (GNN) approach we learn the time-dynamics operator of the open system at small and intermediate scale. This subsequently allows us to simulate and extrapolate the time evolution of the gas with particle numbers approaching those of the experimental realization. We consider the size distribution of scale-free avalanches of atomic excitations, one of the characteristics of SOC, as a function of the gas' temperature. We discuss the implications of this pertaining to the absorbing-state phase transition and its replacement by an extended Griffith's phase at low temperature. |
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N01.00115: Experiments in periodic driving of Bose-condensed lithium Jeremy Tanlimco, Ethan Q Simmons, Roshan Sajjad, Eber Nolasco-Martinez, David M Weld Driven quantum degenerate gases represent a versatile platform for exploring quantum dynamics. Our optical lattice experiments with Bose-condensed lithium lie at the two "extremes" of the spectrum of periodic driving: sharp delta-function-like pulses and sinusoidal amplitude modulation. Delta kicking can realize the quantum kicked rotor, a paradigmatic model of quantum chaos; we recently demonstrated that an interacting kicked rotor exhibits sub-diffusive many-body dynamical delocalization. In band synthesis experiments using sinusoidal amplitude modulation, both Floquet's and Bloch's theorems apply, creating a toroidal Brillouin zone periodic in both quasi-momentum and quasi-energy. Closed loops in the resulting Floquet-Bloch bands represent a novel platform for compact continuously-trapped atom interferometry and sensitive force measurement. In analogy to magic wavelengths used in optical lattice clocks, magic band structures can cancel the first-order trap amplitude noise sensitivity of such Floquet-Bloch atom interferometers. |
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N01.00116: Tunable instability and long-lived density modulations in hydrodynamic dipolar Fermi gases. Reuben R Wang, John L Bohn Recent experiments have demonstrated collisional shielding of heteronuclear molecules with microwave and DC electric fields, allowing stable hydrodynamic samples of ultracold polar molecular gases. Just as predicted and observed in the quantum degenerate regime, nondegenerate hydrodynamic gases can also experience collapse due to the attractive dipolar mean-field at large enough dipole moments. However, we find that this collapse is surpressed by kinetic and collisional effects, leading to the existence of a long-lived density modulated mode. We present the conditions required to achieve this long-lived mode, and their expected lifetimes due to thermal fluctuations. |
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N01.00117: Investigating Many-body Quantum Transport in Momentum Space using Kicked Ultracold Gases Nicolas Williams, Jun Hui See Toh, Xinxin Tang, Carson Patterson, Olivia Peek, Mengxin Du, Ying Su, Chuanwei Zhang, Subhadeep Gupta Understanding the simultaneous effects of both many-body interactions and disorder is at the core of developing a realistic model for quantum transport in real materials. We have leveraged the precision and tunability of ultracold atoms, specifically bosonic 174-Yb, to observe the 3D many-body Anderson metal-insulator transition in synthetic momentum space using quasi-periodic kicks of standing-wave laser pulses. We observe interaction-driven delocalization of a non-universal sub-diffusive nature, pushing the transition boundary to lower values of tunneling and disorder parameters [1, 2]. The experimental investigation is compared with numerical simulations using the Gross-Pitaevskii equation. We will also report on progress towards studies of out-of-equilibrium quantum dynamics of kicked quantum gases of paired 6-Li. We load 6-Li into an optical dipole trap after D1 laser cooling. Using a magnetic Feshbach resonance, both tunable and strong interactions and pairing across the BEC-BCS crossover can be achieved in this system. As compared to the prior study with bosonic ytterbium, interaction-tunable fermionic lithium allows access to both larger areas of parameter space and different quantum statistics in the investigation of many-body quantum transport. |
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N01.00118: Probing spin correlations and thermalization in a dipolar ensemble Bihui Zhu, Youssef Aziz Alaou, Sean Robert Muleady, William Dubosclard, Tommaso Roscilde, Ana Maria Rey, Bruno Laburthe-Tolra, Laurent Vernac Motivated by recent efforts to develop quantum platforms with cold atoms featuring dipolar interactions, we theoretically investigate the quantum dynamics of atoms frozen in space and interacting with long-range dipolar interactions. We focus on high-spin systems and analyze the growth of quantum correlations and the relaxation towards thermalization. We analytically find the long-time thermal behaviors as well as study the role of symmetries and long-range interactions. We further compare our results with a recent experiment using a large number of chromium atoms and probe the buildup of quantum correlations. |
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N01.00119: Measuring Talbot revivals with a matter-wave microscope Justus Brüggenjürgen, Mathis Fischer, Nora Bidzinski, Christof Weitenberg Imaging is crucial for gaining insight into physical systems. In the case of ultracold atoms in optical lattices, quantum gas microscopes have revolutionized the access to quantum many-body systems by resolving single lattice sites. However they are limited to investigating 2D systems and are technically demanding. |
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N01.00120: Quantum gas microscopy of the Fermi-Hubbard model in optical superlattices Thomas Chalopin, Dominik Bourgund, Sarah Hirthe, Petar Bojovic, Si Wang, Immanuel Bloch, Timon A Hilker In the past few years, quantum gas microscopy has proven to be a valuable tool for the experimental exploration of the low-energy quantum many-body states of the Fermi-Hubbard model. More recently, a number of experiments have shifted their interest towards lattice geometries which go beyond the simple square lattice, extending the scope of quantum simulation towards more exotic states. Here, I will report report on our recent implementation of bichromatic optical superlattices in our 6Li quantum gas microscope. The phase stability and tunability granted by our design provide the necessary tools to implement novel cooling protocols and preparation techniques in tailored geometries. In combination with the single-site spin and density resolution of our apparatus, such superlattice-based protocols open the way towards the exploration of the pairing mechanisms at play in the low energy doped Fermi-Hubbard model. |
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N01.00121: Negative absolute temperature states in frustrated optical lattices: towards the kagome flat band Luca Donini, Mehedi Hasan, Sompob Shanokprasith, Daniel Braund, Tobias Marozsak, Tim Rein, Max Melchner von Dydiowa, Daniel G Reed, Tiffany Harte, Ulrich Schneider We report on an ultracold-atom setup implementing a variety of hexagonal lattices including triangular and kagome lattices. Both display geometric frustration that gives rise to two non-equivalent maxima for the ground band of the triangular lattice, and a flat band in the kagome case. |
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N01.00122: Self-oscillating pump in a topological dissipative atom–cavity system Simon E Hertlein, Alexander Baumgärtner, Davide Dreon, Xiangliang Li, Tilman Esslinger, Tobias Donner The time evolution of an quantum system can be strongly affected by dissipation. Although this mainly implies that the system relaxes to a steady state, in some cases it can bring to the appearance of new phases and trigger emergent dynamics. In our experiment, we study a Bose-Einstein Condensate dispersively coupled to a high finesse resonator. The cavity is pumped via the atoms, such that the sum of the coupling beam(s) and the intracavity standing wave gives an optical lattice potential. When the dissipation and the coherent timescales are comparable, we find a regime of persistent oscillations where the cavity field does not reach a steady state. In this regime the atoms experience an optical lattice that periodically deforms itself, even without providing an external time dependent drive. Eventually, the dynamic lattice triggers a pumping mechanism. We will show complementary measurements of the light field and of the atomic transport, proving the connection between the emergent non-stationarity and the pump. |
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N01.00123: A Fermi Gas Microscope with a Tunable Lattice Geometry Lev H Kendrick, Muqing Xu, Anant Kale, Youqi Gang, Martin Lebrat, Markus Greiner We report on a next-generation optical lattice for quantum gas microscopy of ultracold fermionic lithium. By phase-locking and interfering the lattice beams, the lattice geometry can be tuned to realize triangle, honeycomb, and non-bipartite square geometries, enabling us to study strongly correlated phases in the Hubbard model beyond the standard square lattice band structure. By continuously tuning from a square to a triangular geometry, we were able to introduce geometric frustration into the system and investigate its magnetic order upon doping. We are actively exploring novel quantum phases in other geometries by combining the tunable lattice with a digital micromirror device. |
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N01.00124: Transport in the mass-imbalanced 1D Fermi-Hubbard model Thomas G Kiely, Erich J Mueller We study transport in the mass-imbalanced 1D Fermi-Hubbard model using infinite tensor network techniques. We develop a simple model for the frequency dependence of the optical conductivity, valid for strong interactions and large mass imbalances, based on locally-constrained fluctuations. Additionally, we propose a procedure to study these current-current correlators in cold atom experiments. |
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N01.00125: Insulating BECs, pattern formation, and emergent gauge fields in strongly tilted optical lattices Ethan A Lake, Senthil Todadri, Jung Hoon Han, Hyun-Yong Lee We Bose- and Fermi-Hubbard models whose dynamics conserves total center of mass, a situation which can arise in strongly tilted optical lattices. The bosonic models realize a phase of matter which contains a Bose-Einstein condensate, but which is not a superfluid. They also possess a universal tendency to "fracture" into an exotic glassy state that exhibits spontaneous pattern formation, with implications for experiments on spinning BECs. The fermionic models are described at low energies by fermions that strongly interact with an emergent gauge field, offering a novel route towards studying non-Fermi liquids and gauge theories. I will give an overview of the analytic and numerical work behind these results, with a particular focus given on experimental protocols for realizing these exotic phases in the lab. |
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N01.00126: Quantum gas microscopy of triangular-lattice Mott insulators Jirayu Mongkolkiattichai, Liyu Liu, Davis A Garwood, Jin Yang, Peter Schauss Ultracold atoms in triangular optical lattices are a versatile platform to study strongly correlated systems in which exotic states of matter appear due to the interplay between charge and magnetic order. Large degeneracies in the many-body ground state of triangular lattices could result in a quantum spin liquid that has been numerically predicted to appear between the metallic and magnetically ordered phases [1]. Kinetic frustration is another interesting feature that leads to destructive interference between paths of holes, leading to antiferromagnetic polarons in hole-doped regime even at elevated high-temperatures [2]. Here, we report on the observation of lithium-6 Mott insulators in a frustrated triangular Hubbard system. The Mott insulators are fit to Determinant Quantum Monte Carlo (DQMC) and Numerical Linked-Cluster Expansions (NLCE) calculations [3]. We observed temperatures of the system below the tunneling strength in the lattice, which are consistent with temperatures extracted from spin-spin correlations [4]. Finally, we demonstrate a doublon detection technique using a microwave transfer similar to ref. [5]. We are planning to introduce nearest-neighbor interactions in the frustrated triangular system using Rydberg-dressing implementing an extended triangular Hubbard model which is predicted to host a variety of exotic quantum phases. |
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N01.00127: FermiQP - A Fermion Quantum Processor Philipp M Preiss, Andreas von Haaren, Robin Groth, Janet Qesja, Gleb Neplyakh, Er Zu, Timon A Hilker, Immanuel Bloch FermiQP is a demonstrator for a neutral atom lattice quantum processor based on ultracold fermionic lithium. |
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N01.00128: Floquet engineering of an optical Kagome lattice Malte Nils Schwarz, Shao-wen Chang, Rowan Duim, Dan M Stamper-Kurn, Charles D Brown Floquet engineering of optical lattices opens the door to a wide variety of physics, from modifying the tunneling parameter to the implementation of artificial gauge fields. Applied to the optical Kagome lattice, Floquet engineering can be used to invert the band structure to generate a flat ground band in the tight binding limit. This generates interaction dominated dynamics and the bosonic ground state is predicted to exhibit a charge-density wave that breaks down when the filling is increased above 1/9. So far, the optical Kagome lattice hasn't been explored experimentally in regards to Floquet engineering. We're building a new apparatus that offers unique control over the phase of the lattice beams, allowing for the implementation of Floquet drives that can generate inverted band structure and more. In addition, we'll be able to explore both bosonic and fermionic dynamics. |
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N01.00129: 2D Bose glass in an optical quasicrystal Bo Song, Jr-Chiun Yu, Shaurya A Bhave, Lee C Reeve, Emmanuel Gottlob, Georgia Nixon, Zhuoxian Ou, Moritz Epping, Ulrich Schneider An optical quasicrystal opens novel opportunities for studying (quasi-)disorder-driven phenomena. In the presence of both interactions and disorder, a Bose glass phase emerges. Here we report on the direct observation of a 2D Bose glass phase in an optical quasicrystal and present studies of both its static and dynamical features. By probing the phase coherence of the system, we observe a superfluid to Bose glass phase transition. Furthermore, we reveal the nonergodic nature of the Bose glass using a coherence restoration sequence. Finally, we investigate dynamical features following a quench between the superfluid and Bose glass regime. Our observations unveil the Bose glass transition in optical quasicrystals and open a new door for studying many-body localization in two dimensions. |
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N01.00130: Programmable Fermi-Hubbard Lattices Benjamin M Spar, Max Prichard, Siddharth Dandavate, Zoe Z Yan, Waseem S Bakr Programmable lattices offer the possibility of exploring multiple lattice geometries in one experimental setup and providing additional tools for creating targeted initial quantum states. Here, we present results showing one and two dimensional realizations of the Fermi-Hubbard model using small systems of optical tweezer arrays with Li-6 atoms. By loading two atoms into the ground state of half the tweezers, adiabatically ramping on additional tweezers, and post-selecting using a spin-resolved imaging scheme in a quantum gas microscope, we create small low entropy correlated tunnel-coupled systems at half filling. As there are technical limitations to scaling the optical tweezer platform to larger system sizes, we present progress towards demonstrating programmable Fermi-Hubbard lattices with interfering beams. These methods open the door for microscopic studies of fermionic phases in novel lattice geometries. |
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N01.00131: All Optical Production of Degenerate Fermi gas and Quantum simulation in Optical lattices Athira Krishnan Sreedevi, Haotian Song, Rishav Koirala, Kai Dieckmann Experiments with Ultracold atoms opens the possibility to investigate quantum many-body physics in a controllable environment. Using ultracold atoms in optical lattices can be seen as an implementation of a quantum simulator with exceptional purity and the system can be engineered using tools that are developed in the field of atomic physics over the last few decades. With the high degree of tunability and the possibility of efficient detection techniques, these systems opened the pathway to a wide variety of applications in several fields especially in condensed matter physics. |
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N01.00132: Dipolar Lattice Phases in an Erbium Quantum Gas Microscope Michal Szurek, Lin Su, Alexander M Douglas, Vassilios Kaxiras, Ognjen Markovic, Markus Greiner Quantum gas microscopy is a powerful technique for probing and controlling quantum many-body lattice systems. Introducing dipolar atoms into such experiments enables investigation of lattice models with long-range, anisotropic interactions. Here we report the observation of strong dipole-dipole interactions in an erbium quantum gas microscope with single-site resolution. We realize checkerboard and stripe phases of the extended Bose-Hubbard model by tuning the orientation of the atomic dipoles with an external magnetic field. We also present our development of optical potential shaping to realize different system geometries and compensate disorder. In addition, we detail progress on controlling the fermionic isotope of erbium to investigate Fermi-Hubbard physics. |
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N01.00133: Tweezer-programmable Hubbard models and boson sampling Aaron W Young, Shawn Geller, William J Eckner, Nathan A Schine, Nelson Darkwah Oppong, Alec Cao, Scott Glancy, Emanuel Knill, Adam M Kaufman By combining atom rearrangement via optical tweezer arrays with the high-fidelity optical cooling enabled by narrow-line transitions present in alkaline earth atoms, we are able to deterministically prepare nearly arbitrary Fock states of bosonic atoms in a Hubbard-regime optical lattice with high fidelity. These states can be evolved in the lattice to study sampling problems involving interfering bosons with up to 180 particles. Moreover, the tweezers provide programmable control over the lattice potential, allowing for implementations of various quantum algorithms, like spatial search, as well as routes towards stronger certification of these sampling problems in the future. This suite of capabilities constitutes a powerful tool for studying and controlling Hubbard dynamics, but could also be used to directly assemble and probe ground states in such models. |
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N01.00134: Reversal of quantised Hall drifts at non-interacting and interacting topological boundaries Zijie Zhu, Marius Gachter, Anne-Sophie Walter, Konrad Viebahn, Tilman Esslinger Boundaries between topologically distinct materials give rise to gapless edge modes whose robustness is fundamentally and technologically relevant. Therefore, it is crucial to gain a better understanding of topological edge states, both regarding their transport properties as well as their response to interparticle interactions. Here, we experimentally study quantised Hall drifts in a harmonically confined topological pump of non-interacting and interacting ultracold fermionic atoms. We find that quantised drifts halt and reverse their direction when the atoms reach a critical slope of the confining potential, revealing the presence of a topological boundary. The drift reversal corresponds to a band transfer between a band with Chern number C = +1 and a band with C = -1 via a gapless edge mode, in agreement with the bulk-edge correspondence for non-interacting particles. We establish that a non-zero repulsive Hubbard interaction leads to the emergence of an additional edge in the system, relying on a purely interaction-induced mechanism, in which pairs of fermions are split. |
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N01.00135: COLD ATOMS, IONS, MOLECULES, AND PLASMAS
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N01.00136: Quantum science with a dual-species Rydberg array Conor Bradley, Ryan White, Kevin Singh, Shraddha Anand, Vikram Ramesh, Hannes Bernien Arrays of neutral atoms are a powerful platform for quantum information processing and quantum simulation. In this poster we will present developments from our dual-species array of rubidium and cesium atoms. With this system we recently realized crucial capabilities for neutral-atom processors, including mid-circuit measurements and real-time feed-forward, which we leveraged to mitigate correlated errors in a 2D array of up to 120 atomic qubits [1]. Here we will show experimental and theoretical progress in the implementation of dual-element Rydberg gates, the key remaining ingredient to perform non-destructive stabilizer measurements and investigate quantum error correction. We will further discuss novel opportunities offered by asymmetric intra- and inter-species interactions for multi-qubit gates, state preparation protocols, and quantum simulation. |
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N01.00137: A programmable array of strontium clock qubits Alec Cao, William J Eckner, Nelson Darkwah Oppong, Aaron W Young, Nathan A Schine, Adam M Kaufman Alkaline-earth tweezer arrays are a powerful tool for manipulating atomic ensembles with access to narrow-linewidth optical transitions. Interfacing these arrays with the technologies of Rydberg excitation and optical lattices naturally enables the exploration of many-body simulation, information processing and quantum-enhanced metrology in a single platform. Here we report on creating a programmable spin model of optical clock qubits using strontium atoms implanted into an optical lattice. Spin squeezing on the clock transition is performed by using Rydberg dressing to realize finite-range Ising interactions, while high-fidelity 2-qubit entangling gates are achieved in the resonant regime. Optimal control provides a promising route toward higher degrees of squeezing and further improved gate fidelities. To augment differential clock comparisons, we additionally demonstrate local Z-gates by patterning the lattice with tunable and well-controlled tweezer light shifts. |
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N01.00138: Fast feed-forward cancellation of laser phase noise for cold atom experiments Tom Denecker-Desmonts, Sylvain DE LESELEUC, Yeelai Chew, Takafumi Tomita, Seiji Sugawa, Tirumalasetty Panduranga Mahesh, Rene Villela, Kenji Ohmori Lasers are key elements in numerous fields across science. Its technology has been evolving at an impressive rate for the past 60 years. Although great progress has been achieved, for experiment requiring high precision such as cold-atom quantum computing [1], lower noise is always desirable, especially for quantum gates with Rydberg atoms. The fidelity of the gate essentially relies on the stability of (i) the laser intensity, for which techniques are readily available, and (ii) the laser phase [2,3]. Solid-state lasers show remarkable performance both in terms of intensity and phase noise; however, their cost remains high and are not available for every wavelength. Therefore, techniques for reducing the noise of other lasers such as diode lasers are of interest. In this presentation, we report on a simple approach to quantify fast phase noise in laser sources and a feedforward technique for phase noise cancellation at high Fourier frequencies. Using this alloptical-fiber system, we successfully reduce phase noise by 30 dB for Fourier frequencies ranging from 2 MHz to 10 MHz. With its simple assembly, this system makes low phase noise laser light accessible to a greater number of researchers and stimulates experimental fields such as cold atom experiments. This system is ready to be implemented into Rydberg atom experiments and should allow for improved fidelity. I will present its scheme and discuss future upgrades of the system. |
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N01.00139: Towards a modular experiment for variable optical traps from single-atom qubits to condensates Bharath Hebbe Madhusudhana, Katarzyna Krzyzanowska, Malcolm G Boshier Neutral atoms trapped in optical potentials have emerged as a promising platform for Quantum Technologies to study a rich spectrum of applications, including quantum metrology, quantum computation, and quantum simulation of many-body systems. The choice of application often dictates specific engineering solutions, which rapidly becomes a time-consuming and expensive task with the growing sophistication of the platform. Here we introduce a modularized, compact design for single atoms trapped in a tweezer array alongside a Bose-Einstein Condensate (BEC), and report on the progress of its build-up. |
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N01.00140: Deltaflow.Control: A de-centralised control system architecture for large-scale ion trap and cold atom quantum computing Andrea Husseiniova, Marco Ghibaudi, Gianmarco Girau, Robin Sterling A suitable control system is pivotal for sophisticated experiments in all atomic and molecular (AMO) physics. In particular, large-scale ion-trap and cold-atom quantum computing will employ some of the most complex control systems ever built. These will have to support measurement-heavy workflows, fast feedback with tight latency constraints, and be scalable in hardware and software. Here, we present the architecture of Deltaflow.Control, a control system designed with large-scale error-corrected quantum computing in mind. Its de-centralised architecture pushes processing to the periphery of the system reducing latency of feedback and feedforward loops. In the periphery, Atomic Control Units (ACUs) enable multi-tone generation of phase-coherent pulses with sub-nanosecond accuracy. We show execution of instructions on all channels without bottlenecks eventually scaling to multiple boards and larger heterogeneous systems. Finally, we present an intuitive and deterministic programming model and a user interface for quick control, tune up and experiment orchestration crucial to saving time in the lab and enabling more discoveries. Our goal is to provide a powerful control system that can handle the growing list of requirements for error-corrected, large-scale quantum computing. |
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N01.00141: Optimization of Holographic Arrays of Optical Tweezers for Ultra-Precise Manipulation of Atoms Martin Poitrinal, Sylvain DE LESELEUC, Takafumi Tomita, Yeelai Chew, Tirumalasetty Panduranga Mahesh, Seiji Sugawa, Kenji Ohmori Optical tweezers are a major tool for the manipulation of individual cold atoms, with various applications such as quantum chemistry, metrology, or quantum simulation and computing. In most experiments, such as the one relying on Rydberg blockade, laser-cooled atoms are left in a state of thermal motion in the tweezers, where their finite temperature (typical several tens of μK) makes them explore the bottom ~10 % of the trap (depth of 0.5-1 mK). For more demanding experiments (e.g., to assemble molecules or for metrology), the atoms can be further cooled to the motional ground-state of the tweezers (for example with Raman sideband cooling). In that case, thermal fluctuations are suppressed and the atom’s positioning is only limited by quantum fluctuation, i.e., the finite size of the tweezers ground-state wavefunction. |
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N01.00142: Towards programmable ytterbium tweezer array at KRISS Yunheung Song, Jeong Ho Han, Jae Hoon Lee, Jongchul Mun Neutral atoms in programmable tweezer array have emerged as a versatile platform for quantum computation, quantum simulation, and quantum metrology. Especially, tweezer array of two-electron atoms is recently developing, seeking new opportunities over one-electron atoms. In this poster, we present progress towards two-electron-atom tweezer array of ytterbium atoms at Korea Research Institute of Standards and Science (KRISS), where researches on quantum gas and optical clock have been being conducted with ytterbium. We are aiming to use the ytterbium tweezer array for hybrid analog-digital quantum computation and simulation, and optical frequency metrology, utilizing ytterbium's new opportunities such as optical clock transition, nuclear spin qubit, single-photon Rydberg transition, and ion-core transition. |
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N01.00143: Programmable quantum simulators for materials discovery Kent Ueno, Parth K Padia, Artem Zhutov, Anastasiia Mashko, Christopher M Wyenberg, Alexandre Cooper-Roy Quantum materials exhibit emergent phenomena that may enhance the performance of devices and enable new applications. However, predicting the properties of materials in strongly-correlated regimes is difficult due to the limitations of classical simulation tools. Quantum simulators based on quantum processors without error correction may supplement classical tools to accelerate the discovery and design of new materials. Here we report on our progress developing quantum simulators based on configurations of neutral atoms with Rydberg-mediated interactions. Under suitable control protocols, these simulators realize lattice spin models with dynamic connectivity graphs that map onto various physical models, such as the spin-exchange interaction realizing spin transport and the Dzyaloshinskii–Moriya interaction realizing magnetic skyrmions. To experimentally realize these models with more than a thousand spins, we present efficient algorithms to solve reconfiguration problems, low-latency feedback systems to actuate multiplexed arrays of laser beams, and closed-loop optimization routines to prepare large, homogeneous arrays of optical traps. |
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N01.00144: Dual-type Dual-element Atom Array for Quantum Computation and Simulation Wenchao Xu Quantum science promises great potential to revolutionize our current technologies. The past few years have witnessed a rapid progress on using arrays of individually trapped atoms as a programmable quantum processor. However, several predominant challenges remain, including reconfigurable individual addressability for qubit/spin operation and non-demolish selective detection, which lead to limited efficiency in implementing quantum algorithm, low experimental repetition rate, and preclude applications of many quantum error correction protocols. Here, we are building a novel architecture that sidesteps these challenges and enable experimental study on frontier topics in quantum information dynamics, with the long-term goal aiming for a fault-tolerant general-purpose quantum computer. This architecture combines an array of individually trapped ytterbium atoms and an array of rubidium atomic ensembles in a bilayer structure, with each layer has its own unique functionality and the interlayer interaction can be tuned with external electric field rapidly via Förster resonance. Spins/qubits are encoded with the electronic states of Yb atoms, while the Rb atomic ensembles perform ancillary operations on the nearby Yb atoms, including rapidly reconfigurable local qubit operation, and fast, non-demolish detection. With these newly developed techniques, this platform can implement previously inaccessible protocols on efficient generation of target quantum states, and is compatible with quantum error correction. |
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N01.00145: Towards quantum simulations of nuclear physics using optical tweezer arrays of Yb atoms Zeyu Ye, Kevin G Bailey, David P DeMille, Matthew R Dietrich, Francesco Granato, Peter Mueller, Thomas P O’Connor, Michael N Bishof Quantum devices provide an opportunity to solve significant problems in nuclear physics, such as quantum many-body interactions, hadronization, and the nuclear matter equation of state, but large-scale, fault-tolerant, universal quantum computers for these tasks are still years away. Nevertheless, quantum simulators gain insight into such systems by mimicking their behavior. We trap ytterbium atoms in reconfigurable optical tweezer arrays, which are a promising platform for quantum simulation. The optical clock transition from the ground state enables precise quantum state manipulation with a long coherence time. We propose to study quark-level effective theories for quantum chromodynamics (QCD) with strong interaction enabled by coupling to Rydberg states. By expressing the Nambu-Jona-Lasinio (NJL) model as spin operators via Jordan–Wigner transformation, our system is suitable to explore chiral symmetry breaking and other non-perturbative phenomena in QCD. |
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N01.00146: Towards fault-tolerant quantum computing using 171Yb metastable state qubits Bichen Zhang, Shuo Ma, Pai Peng, Genyue Liu, Junlan Jin, Jeff D Thompson Neutral atoms in optical tweezer arrays is a blooming frontier in the field of quantum sciences. In particular, alkaline earth atoms (AEAs), including Yb, offer unique advantages for quantum computing due to their rich energy level structure. Recently, we demonstrated universal control of qubits encoded in the nuclear spin of the 1S0 ground state, including one- and two-qubit gates [1]. In this poster, we will present ongoing work to implement qubits in the nuclear spin of the metastable 3P0 state, which offers numerous potential advantages including single-photon excitation to the Rydberg state, efficient and robust local control using light shifts [2], and efficient, low-overhead quantum error correction (QEC) using erasure conversion [3]. We will also present an optical modulator based on a combined spatial light modulator and digital micromirror device capable of locally programming gates on over 10,000 sites at update rates of 47 kHz, with a contrast over 40,000:1 and a crosstalk below 10-4 at spot separations of 5 beam waists. Finally, we will discuss novel approaches to QEC leveraging the biased erasure error model of metastable 171Yb qubits, enabling surface code thresholds exceeding 8%. |
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N01.00147: Next-Generation Rb Atom Array Quantum Testbed Jinen Guo, Simon Hollerith, Pavel Stroganov, Neng-Chun Chiu, Mohamed Abobeih, Sebastian Geier, Tout T Wang, Markus Greiner, Vladan Vuletic, Mikhail D Lukin Neutral atoms trapped in optical tweezer arrays have emerged as a leading platform for quantum information processing and quantum simulation. This platform features highly scalable atom arrays with programmable geometry, high-fidelity entanglement via Rydberg blockade, and entanglement-preserving atom transport that enables arbitrary connectivity. We report on progress towards building a next-generation rubidium atom array platform, which will be a testbed for approaches to significantly increasing the number of qubits while performing higher-fidelity Rydberg excitations. |
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N01.00148: Continuous Symmetry Breaking in a 2D Dipolar Rydberg Array Vincent S Liu, Cheng Chen, Guillaume Bornet, Marcus Bintz, Gabriel Emperauger, Lucas Leclerc, Pascal Scholl, Daniel Barredo, Johannes Hauschild, Johannes Hauschild, Shubhayu Chatterjee, Michael Schuler, Andreas M Läuchli, Michael P Zaletel, Norman Y Yao, Antoine Browaeys We investigate strongly correlated ground states of the dipolar XY model in two dimensions. This model is naturally realized by a programmable Rydberg quantum simulator using a pair of Rydberg states as the spin encoding. On the square lattice, we demonstrate that continuous symmetry breaking can occur at finite temperatures owing to the power-law interactions. On the experimental front, we prepare correlated low-temperature states of both the XY ferromagnet and the XY antiferromagnet using an adiabatic protocol. Turning to the Kagome lattice, we numerically demonstrate that the model exhibits a gapless Dirac spin liquid ground state. We further discuss experimental signatures of the Dirac spin liquid and experimental progress in the adiabatic preparation of this phase. |
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N01.00149: Towards synthetic dimensions in potassium Rydberg atom arrays Ivan Velkovsky, Tao Chen, Chenxi Huang, Jacob Covey, Bryce Gadway Trapped neutral atoms in an optical tweezer array are a versatile and powerful quantum simulation platform. Here we present our work towards implementing a synthetic lattice of microwave-coupled Rydberg states in a defect-free 1D tweezer array of single 39K atoms. We demonstrate efficient loading and cooling of potassium atoms into a uniformized 1D tweezer array, as well as evidence of coherent two-photon excitation to a Rydberg state. We also present progress towards producing a defect-free array via rearrangement of loaded tweezers. Finally, we explore Hamiltonian engineering of strongly interacting many-body models via the combination of microwave coupling of Rydberg levels and dipole-dipole interactions between atoms in adjacent tweezers. |
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N01.00150: A dual-species atom array with alkali and alkaline-earth atoms Yi J Zhu, Giulia Semeghini We present our ongoing efforts toward creating a programmable neutral atom array based on a mixture of alkali and alkaline-earth atoms. Single-species atom arrays have recently demonstrated exciting applications in quantum information, simulation, and metrology. The addition of a second atomic species, with different features, opens new possibilities for engineering many-body interactions, performing non-demolition measurements on complex entangled states, and developing new architectures for quantum information processing. Here we present progress on the realization of this new quantum platform, discussing the choice of atomic species, design considerations, and concrete near-term applications. |
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N01.00151: Self-organization in the avalanche from molecular Rydberg gas to ultracold plasma Amin Allahverdian, Ruoxi Wang, Kevin Marroquin, Smilla Colombini, Abhinav Prem, John Sous, James S Keller, Edward R Grant Long-range correlations can steer dissipative many-body systems to transient states with emergent dynamics far different from the equipartition of energy, where small driving forces produce local fluctuations that trigger avalanche-like energy dissipation events. Driven dissipation sometimes leads to size distributions described by power laws signifying self-organization to a scale-invariant critical state. Recent experiments in Strasbourg and Durham have found such signs of self-organized criticality in the off-resonant excitation of a Rydberg gas in the anti-blockade regime, where interaction-induced line shifts and broadening determine size distributions of transition avalanches that underlie a physics of self-organization. A similar mosaic of local kinetic processes and long-range interactions drives the relaxation of a dense molecular Rydberg gas of nitric oxide to form an ultracold plasma exhibiting a scale-invariant avalanche-size distribution described by a power-law: P(N) = Nawith a = -1.37. An evident balance in the optimum density, ρ0, to form a long-lived plasma for spectroscopically selected intervals of initial principal quantum number, n0, reflects a sensitivity to the Rydberg orbital radius compared with the average distance between nearest neighbors. Non-linearity enters in the variation of dipole-dipole coupling and unimolecular dissociation with the evolving electron binding energy. Owing to these factors, n0 and ρ0 constitute important control parameters to consider in models that seek to explain the apparent self-organized criticality of this system in terms of the dynamics of microscopic interactions. |
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N01.00152: Local dissipation drives global relaxation in a molecular ultracold plasma with on-site disorder and long-range dipolar interactions Ruoxi Wang, Kevin Marroquin, Amin Allahverdian, Smilla Colombini, Abhinav Prem, John Sous, James S Keller, Edward R Grant The nitric oxide ultracold plasma evolves from a state-selected Rydberg gas to form a disordered ensemble of dipoles that populates a distribution of Rydberg and excitonic states concentrated in an energy interval within a few hundred GHz of the ionization threshold, doped by a trace population of more deeply bound Rydberg molecules. This residue of lower-n molecules includes a fraction that retains the initially selected principal quantum number, n0. l-mixing collisions drive these molecules to occupy non-penetrating states of high-l. Excitation by mm-wave radiation tuned to resonance with n0l(2) to (n0 ± 1)d(2) transitions depletes the plasma signal to an amplitude near zero, even though delayed selective field ionization spectra show that the distribution of states evolves by then to contain fewer than one percent in the n0 level resonant with the mm-wave field. Reading the nature of this coupling in the linewidths and depths of these depletion resonances, we see direct evidence that predissociation, which transfers population from the spectroscopically active (n0 ± 1)d(2) states to a system of free N(4S) + O(3P) atoms, bridges the closed plasma ensemble to a thermal continuum, in effect creating an open quantum system that combines the plasma with the reservoir of free atoms. Motivated by these results, we have constructed a minimal model of disordered one-dimensional spins evolving under a Lindblad master equation with local dissipation that qualitatively reproduces the experimental observations. |
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