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 F01: Poster Session I (4:00pm-6:00pm PT)Poster
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Room: Exhibit Hall C |
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F01.00001: ATOMIC, MOLECULAR, AND CHARGED PARTICLE COLLISIONS
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F01.00002: Quantum Diffractive Universality Signatures in Ensemble Heating Avinash Deshmukh, Riley A Stewart, Pinrui Shen, James L Booth, Kirk W Madison In previous work, we have demonstrated that quantum diffractive collisions between a thermal background gas and a cold, trapped sensor gas follow a universal law for certain collision partners. Specifically, we found that the sensor gas loss rate from a trap of depth U follows a universal function P(U/Ud) of the trap depth scaled by a diffractive energy scale Ud. Here we use this law to predict the evolution of the energy distribution of the sensor gas, and we compare this prediction to experimental measurements and numerical simulations for Rb+Ar collisions. We also generalize the evolution equation for any interaction potential energy surface and show how the measured evolution can be used to identify if a collision pair obeys universality or not. |
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F01.00003: Accurate measurement of the loss rate of cold atoms due to background gas collisions for the quantum-based cold atom vacuum standard Stephen P Eckel, Daniel S Barker, James A Fedchak, Jacek Klos, Julia Scherschligt, Eite Tiesinga, Nikolai N Klimov We present experimental measurements of thermalized collisional rate coefficients of ultra-cold 7Li and 87Rb colliding with room-temperature He, Ne, N2, Ar, Kr, and Xe. In our experiments, a vacuum metrology standard---a combined flowmeter and dynamic expansion system---is used to set a known number density for the room-temperature gas in the vicinity of magnetically trapped ultracold 7Li or 87Rb clouds. Each collision with a background atom or molecule removes a 7Li or 87Rb atom from its trap and the change in the atom loss rate with background gas density is used to determine the thermalized loss rate coefficients with fractional standard uncertainties that are better than 1.6 % for 7Li and 2.7 % for 87Rb. We find consistency between the measurements and recent quantum-scattering calculations of the loss rate coefficients [J. Klos and E. Tiesinga, J. Chem. Phys. 158 014308 (2023)] except for the loss rate coefficient for 87Rb colliding with Ar. Nevertheless, the agreement between theory and experiment for all other studied systems provides validation that a quantum-based cold-atom vacuum standard (CAVS) serves as both a sensor and primary standard for vacuum. Future work includes validating the range of operation of the CAVS and extending the list of background gases to other common gases found in vacuum systems, including CO, CO2, H2, and O2. |
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F01.00004: nuclear spin relaxation in cold atom-molecule collisions Rebekah Hermsmeier, Xiaodong Xing, Timur V Tscherbul We use rigorous quantum scattering calculations to explore the quantum dynamics of nuclear spin relaxation in cold collisions of 13CO (1Σ+) molecules with 4He atoms in an external magnetic field. We find that collision-induced nuclear spin relaxation in the ground rotational manifold of 13CO occurs extremely slowly as long as the temperature remains small compared to the spacing between the ground and the first excited rotational levels. |
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F01.00005: Effects of PES Uncertainty on Collision Observables: Comprehensive Analysis of Quantum Diffraction Universality Katherine R Herperger, Pinrui Shen, Erik B Frieling, Denis Uhland, Riley A Stewart, Avinash Deshmukh, Roman V Krems, James L Booth, Kirk W Madison Quantum diffractive collisions between an impinging ambient gas and stationary sensor particles in a vacuum magneto-optical trap follow a universal law, which allows one to bypass time-intensive scattering calculations and use the setup as a self-defining gas pressure sensor. This was validated earlier for two systems of collision partners Rb+N2 and Rb+Rb. We show that deviations from universality can be expected for systems with a small reduced mass and a small C6 coefficient in the interaction potential energy surface (PES). We describe how the coupled-channel quantum scattering calculations for Li+H2 and Rb+H2 are essential to concluding that Rb+H2 does not follow universality. Additionally, a key feature of universality is the insensitivity of collision observables to changes in the short-range potential. We illustrate how the scattering rate changes in response to variation of the short-range PES for a universal (Rb+N2) and non-universal (Rb+H2) system. By analyzing the trends in these systems, we aim to employ scattering rate sensitivity to the underlying PES as a quantitative measure of universality. |
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F01.00006: PyQCAMS: A Quasi-Classical Atom-Molecule Simulation in Python Rian Koots, Jesus Perez Rios The quasi-classical trajectory (QCT) method for studying molecular reaction dynamics is a standard theoretical approach to studying molecular reaction dynamics [1]. If a reaction falls within the bounds of a classical approximation, such that its quantum mechanical effects are negligible, the QCT method can be used to calculate reaction cross sections, opacity functions, and final state distributions at reasonable computational cost as compared to full quantum dynamics simulations. We present a quasi-classical atom-molecule simulation in Python (PyQCAMS), which performs a QCT calculation of an atom - diatomic molecule system. The user has control over which atom, diatomic molecule, and interaction potential energy between each atom. Results are presented for a collision between an atom (Ca) and a diatomic molecule (H2). |
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F01.00007: Spin-Exchange Rate Coefficients for Rb-Xe and Cs-Xe Measured Using Rate Balance Chelsea V Weaver, Brian T Saam, Adnan I Nahlawi Hyperpolarized noble gases, produced via spin-exchange optical pumping (SEOP), have many applications including precision magnetometry and lung MRI. The rate coefficient kse characterizes the collisional transfer of angular momentum from the alkali metal to the noble gas; there are three main methods [1] to measure it. The rate-balance method requires no assumptions about wall-relaxation, which for 129Xe is often non-negligible and temperature-dependent. Normally, the method requires a determination of both alkali-metal number density [A] and the polarization PA; we are pursuing a variant of this method in which we measure frequency shifts of both the alkali-metal resonance and the 129Xe NMR resonance under the same conditions. Measuring the NMR shift, which is proportional to PA[A], eliminates the need for direct measurement of PA or [A]. Using the expressions for the two frequency shifts [2] and forming their ratio, we obtain: kse-1 = (ΔfXe/ΔfA)([129Xe]τup/gs[2I + 1]), where gs is the electron g-factor, I is the alkali-metal nuclear spin, [129Xe] is the number density of 129Xe, and we have assumed that the enhancement factors [2] κAXe = κXeA = κ0. The characteristic spin-up time τup and the EPR shift ΔfA corresponding to full 129Xe polarization are measured by monitoring the alkali-metal EPR frequency via Faraday rotation. The NMR shift ΔfXe is measured by scanning a weak cw NMR excitation across the129Xe resonance at full 129Xe polarization (in both directions with respect to the applied magnetic field) and monitoring the alkali-metal EPR frequency to trace the NMR spectrum. We present preliminary measurements of kse for both Rb-Xe and Cs-Xe in vapor cells with a gas mixture at pressure on the order of 1 bar with 3% Xe, similar to the composition used in Xe flow-through polarizers. [1] B. Chann, et al., Phys. Rev. A, 66, 032703 (2002); [2] S.R. Schaefer, et al., Phys. Rev. A 39, 5618 (1989). |
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F01.00008: Positronium scattering by polar molecules Robyn S Wilde, Myranda K Selvage, Ilya I Fabrikant Experimental measurements of the total cross section for scattering of Positronium (Ps) by various atomic and molecular targets are very similar to electron scattering cross sections above the Ps ionization threshold [1]. Using a Free Electron Gas model [2] we have previously calculated elastic scattering cross sections for Ps scattering by the homonuclear diatomic molecules N2 and O2 as well as CO2 [3]. To obtain the total scattering cross section we added the Ps ionization cross section which was computed using the binary encounter method. Our calculations confirmed that the total cross section for electron and Ps scattering is similar above the Ps ionization threshold. The present target molecules provide a range of dipole moments from the weakly polar CO to the strongly polar LiF. We find that Ps scattering is similar to electron scattering when the cross sections areplotted as a function of projectile velocity for the targets with smaller dipole moments (CO, HCl). However, we do not see such a similarity for LiF which suggests that the similarity between electron and Ps scattering does not extend to highly polar targets. Below the Ps break-up threshold we observe resonance structures similar to those obtained earlier for the other molecular targets that we have studied. |
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F01.00009: Fine-structure transitions of Si, S, N+ and O2+ induced by collisions with atomic hydrogen Pei-Gen Yan, James F Babb Atomic and ionic fine-structure emission lines are widely observed in astronomy. For the spectra to be useful diagnostics of astrophysical environments collisional excitation and relaxation rate coefficients describing interactions with ambient particles are needed. Here we consider the case of collisions with atomic hydrogen. Based on accurate SiH, SH, NH+ and OH2+ molecular potentials, we will report calculations of fine-structure excitation and relaxation cross sections and rate coefficients in collisions of Si, S, N+ and O2+ with H utilizing a fully-quantum close-coupling method. Applications of the resulting data and extensions of the methodology to other colliding systems will be discussed. |
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F01.00010: Structural analysis of fullerene from e-C60 elastic scattering Jobin Jose, Aiswarya R, Rasheed Shaik, Hari R Varma, Himadri Chakraborty
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F01.00011: Spectroscopy of Highly Charged Ions for Astrophysical and Fundamental Physics Applications Samuel DeMay, Amy Gall, Henry Russell, Anthony G Calamai, Roshani Silwal Plasma conditions seen in astrophysical plasmas such as in the solar corona can be reproduced and probed in a laboratory environment with an electron beam ion trap (EBIT). The recent launch of telescopes sensitive in the infra-red (IR) region highlights the need for spectral data in this region to improve models. In an effort to extend the spectroscopic measurements with an EBIT to the near-IR region, we perform test measurements at the EBIT facility at the Center for Astrophysics (CfA) | Harvard & Smithsonian. The test setup consisted of a photomultiplier tube (PMT), focusing lenses, and a narrow band filter. Well-known emission from Ar ions in the visible region was measured to better understand the challenges created by the hot electron gun and warm surfaces within the EBIT, and to explore the timing capabilities and photon detection efficiency of the PMT. Here, we present the experimental efforts and preliminary results which are the first step in our plans to measure the atomic lifetimes. |
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F01.00012: Atomic Collisions with a Trapped Ion Angela D Graf, Nirav P Mehta, Seth Rittenhouse, Eleanor Trimby, Henrik Hirzler, Henning A Fürst, Arghavan Safavi-Naini, Rene Gerritsma, Rianne Lous We model the collision of a Lithium atom with a trapped Ytterbium ion within the adiabatic hyperspherical approach in one spatial dimension. We propose a strategy that leverages the energy-analytic solutions of quantum defect theory, which can be used impose a short-ranged two-body boundary condition on the adiabatic eigenfunctions. This boundary condition depends on the hyperradius R, and in our numerical scheme must be translated to a particular b-spline basis set at each value of the hyperradius. We present a straightforward method for the computation of the adiabatic potential energy curves and all nonadiabatic couplings, providing a path forward for the calculation of scattering cross sections. We note that this method opens new possibilities for incorporating long-ranged two-body physics into few-body calculations. |
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F01.00013: Hyperradial distribution function of few-body problems: a new arena for extreme value theory Yu Wang, Marjan Mirahmadi, Ahmed A Elkamshishy, Jesus Perez Rios In this work, after studying the capture hyperradius of few-body processes, including van der Waals and charged-neutral interactions, we found that the distribution of the hyperrardius follows a Frechet distribution. In other words, the distribution of the capture hyperradius is independent of the underlying interparticle interaction. We then rationalized and generalized our findings following the Fisher–Tippett–Gnedenko theorem, connecting the extreme value theory and few-body physics. In particular, we use a Monte Carlo technique in hyperspherical coordinates to properly sample all the initial configurations of the particles to extract the capture hyperradius and, with it, the hyperradial distribution. |
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F01.00014: Resonant positron annihilation in pyridine and other aromatic molecules. E. Arthur-Baidoo, J. R. Danielson, D. R. Witteman, S. Ghosh, C. M. Surko Positron-molecule annihilation below the positronium formation threshold is often mediated by the capture of positrons through vibrational Feshbach resonances (VFRs) associated mostly with the fundamental modes. This leads to strong enhancement of the probability of annihilation [1]. The presence of VFRs yields a direct measure of the positron molecule binding energy. This has been reported in several studies, including recent investigations of benzene and its derivatives [2]. Pyridine (C$_5$H$_5$N) and furan (C$_4$H$_4$O) are two examples of heterocyclic aromatic molecules known for their role in medicinal chemistry and pharmaceutical products. In this work, we report new measurements of positron annihilation spectra and binding energy for these molecules, investigated using a high-resolution, trap-based positron beam. The observed features are compared with those reported for benzene and chain hydrocarbons. The dependence on molecular properties such as number of $pi$-bonds, polarizability, and dipole moment is discussed [3]. Outstanding questions are also discussed. [1] G. F. Gribarkin et al., Rev. Mod. Phys. 82, 2557 (2010). [2] S. Ghosh, et. al., Phys. Rev. Lett. 129, 123401 (2022). [3] J. R. Danielson et al., Phys. Rev. A. 106, 032811 (2022). |
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F01.00015: Positron annihilation and threshold positronium formation cross-section in pyridine. James R Danielson, E. Arthur-Baidoo, D. R. Witteman, S. Ghosh, C. M. Surko Measurements of the low energy positron annihilation cross-section of pyridine are presented over the energy range $0 - 10$ eV. The experiments use a high-resolution buffer-gas-trap based beam with a total energy spread of $< 35$ meV. Below $0.5$ eV, as expected, the spectrum is dominated by vibrational feshbach resonances [1]. The focus here are the measurements at and above the positronium (Ps) formation threshold ($approx 2.4$ eV) where the annihilation is dominated by Ps annihilation. The measured cross-section, $sigma_a$, rises from threshold until approximately $4$ eV where $sigma_a$ plateaus and exhibits a gentle oscillation from $4$ eV to $10$ eV. These measurements are shown to be quantitively consistent with the recent Ps cross-section measurements in the energy range 4 - 10 eV [2]. Further, the threshold region ($2 - 4$ eV) is compared to downshifted (by $6.8$ eV), and scaled, high-resolution emph{photoionization} experiments [3]. Surprisingly, there is excellent agreement between the shapes of the two curves implying identical thresholds and the same threshold power law for Ps formation and photoionization. [1] Details in poster by Arthur-Baidoo et al, DAMOP2023. [2] Stevens et al JCP extbf{148}, 144308 (2018). [3] Xie et al. IJMS extbf{303}, 137 (2011). |
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F01.00016: Resonant positron annihilation in benzene and deuterated isotopologues. S. Ghosh, J. R Danielson, E. Arthur-Baidoo, D. R Witteman, C. M Surko Positrons bind to most molecules through vibrational Feshbach resonant (VFR) excitation of fundamental vibrational modes, and this leads to greatly enhanced annihilation rates. Recently, new resonances beyond the fundamental modes have been observed in hydrocarbon and deuterated hydrocarbon molecules [1]. Here, we present the annihilation spectrum for benzene and four deuterated isotopologues as a function of positron energy using a cryogenic, trap-based positron beam (FWHM ~ 22 meV) [2]. The increased energy resolution permits the resolution of many unexpected resonances, likely due to combination and overtone vibrational modes. The relationship of these results to the unique π-bonded structure of benzene is discussed. Although the IR spectra have features associated with combination and overtone modes in this region, it is unclear whether they can provide sufficient coupling to explain the observed enhancements in annihilation. |
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F01.00017: ULTRAFAST AND STRONG FIELD PHYSICS
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F01.00018: Multi-sideband interference structures observed via high-order photon-induced continuum-continuum transitions in helium Divya Bharti, Hemkumar Srivinas, Farshad Shobeiry, Robert Moshammer, Thomas Pfeifer, Aaron Bondy, Kathryn R. Hamilton, Klaus Bartschat, Anne Harth As a continuation of our recent work on argon [1], we report a joint experimental and theoretical study of a three-sideband (3-SB) modification of the ''reconstruction of the attosecond beating by interference of two-photon transitions'' (RABBIT) setup [2-4]. The 3-SB arrangement makes it possible to investigate phases resulting from interference between transitions of different orders in the continuum, independent of a chirp in the harmonics, by comparing the RABBIT phases extracted from specific SB groups formed by two adjacent harmonics [5,6]. While experimentally more challenging than argon, using a helium target has the advantage of a well-defined orbital angular momentum after the 1s --> εp step induced by the high-harmonic radiation, which simplifies the analysis of the results. Furthermore, calculations in the single-active electron (SAE) approximation are expected to be of similar quality as predictions based on much more sophisticated approaches such as the multi-electron R-matrix with time dependence method (RMT) [7]. |
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F01.00019: Wigner time delay in the spillover plasmon resonance region of Na clusters Hari Varma Ravi, Kuldeep Prajapat, Himadri Chakraborty, Rasheed Shaik An earlier theoretical work on sodium metal clusters, Nax, has showed a significant plasmon resonance spillover to the continuum near their ionization thresholds [1]. The study also predicted the existence of an attractive force arising from the self-consistent field induced by many-body interactions that can cause photoemission delay in attoseconds. The present work explores this spillover energy region with an aim to study the ultrafast ionization in the time domain. It particularly focusses on the Wigner time delay approach [2] involving the energy derivative of the ionization phase. The ground state of Nax is described using a jellium-based density functional approach (DFT) with a gradient corrected exchange-correlation functional (LB94). The photoionization dynamics is accounted for using the linear-response time-dependent DFT [3]. |
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F01.00020: Carrier relaxation and displacive coherent phonon motion measured by XUV transient absorption spectroscopy Lorenz B Drescher, Bethany de Roulet, Yoong Sheng Phang, Stephen R Leone We report on the measurement of carrier relaxation and coherent phonon motion in Sb after excitation by a few-cycle NIR pulse measured with XUV transient absorption spectroscopy. Lifting of the Peierl’s distortion in Sb by optical excitation of carriers leads to a well-known oscillation of the lattice position in form of a coherent phonon motion. Following the delay-dependent change of core-level absorption, by using attosecond XUV bursts, permits following this motion and unraveling the interplay of optically excited carriers, their thermal and relaxed counterparts and the lattice motion. The observed dynamics by and large follow the Displacive Excitation of Coherent Phonon Motion model. But the results show that the relaxation of the optically excited carriers plays an influential role on the phase of the cosine-like phonon motion: We find great agreement with recently reported DFT calculations on impulsive forces caused by the optically excited carriers and their momentum relaxation via electron-phonon scattering [1]. The measured oscillation phases hereby allow to extract the energy-dependent lifetime of the momentum relaxation. We furthermore observe transient spectral reshaping of core-level transitions during temporal overlap of the NIR and XUV pulse, which allows us to estimate the coherence lifetime of Sb core-level excitations.
[1] O’Mahony, et al. PhysReLett 123, 8 (2019): 087401.
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F01.00021: High-Order Above Threshold Ionization of Noble Gas Atoms using Sculpted Laser Pulses Allison L Harris We present theoretical simulations of above threshold ionization (ATI) of noble gas atoms using sculpted laser pulses. The time-dependent Schrödinger equation is solved to calculate the ATI energy and momentum spectra, and a classical model that solves Newton’s equations of motion provides a qualitative understanding of the electron motion after ionization. Results are presented for Gaussian and Airy laser pulses with identical power spectra, but differing spectral phases. The simulations show that the third order spectral phase of the Airy pulse causes changes to the timing of ionization and the dynamics of the rescattering process. Specifically, the use of Airy pulses in the ATI process results in a shift of the Keldysh plateau cutoff to lower energy due to a decreased pondermotive energy of the electron in the laser field. Additionally, the number and timing of rescattering events is altered due to the side lobes of the Airy laser pulse, resulting in changes to the high-order ATI plateau. Our results also show that laser pulses with identical carrier envelope phases, and nearly identical envelopes, yield different photoelectron momentum densities, which are a direct result of the pulse’s spectral phase. |
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F01.00022: Using irrational linear slopes to increase the precision of spatial light modulators for attosecond metrology Geoffrey R Harrison, Tobias Saule, Brandin Davis, Carlos Trallero A Trallero We present a method to increase the effective phase bit-depth of Spatial Light Modulators (SLMs) which utilizes an irrational linear slope as is commonly used to deal with the zeroth order effect. The effectiveness of this technique was demonstrated using precise interferometric transient absorption spectroscopy setups. These setups use high harmonic generation in both solids and gases to generate two ultraviolet pulses that interfere in a spectrometer, providing a measurement of the optical phase. An increase in phase control beyond what the SLM's digital processors would dictate was observed. |
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F01.00023: Strong-field-driven dissociation dynamics in CO2+ Hung V Hoang, Uwe Thumm We theoretically investigated strong-field XUV-IR pump-probe dissociative ionization of CO2 in full dimensionality by solving in full (3D) dimensionality the coupled-channel Schrödinger equation for the nuclear motion on five coupled Oppenheimer (BO) potential-energy surfaces. Including ab initio calculated non-BO coupling, laser dipole, and spin-orbit couplings calculated using a multi-configurational self-consistent-field quantum-chemistry code, we provide kinetic energy release (KER) spectra for the O(3Pg) + CO+( X2Σ+) and O+(4Su) + CO(X1Σ+) dissociation channels and their branching ratio. Our KER spectra identify the ro-vibrational excitations of CO+ fragments along a dominant 3ω dissociation paths. Mediated by the nuclear dynamics near a A2Πu and B2Σu+ conical intersection and in good agreement with the experiment of Timmers et al., Phys. Rev. Lett. 113, 113003 (2014), we reproduce a core-hole oscillation period 115 fs. In addition, we find and race as due to quantum beats between specific pairs of vibration and electronic CO2+ states a slower oscillations 62 fs in the CO+ fragmentation channel. |
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F01.00024: Carrier Envelope Phase's Role in Tilted N2 Strong Field Ionization Alex J Schimmoller Recently, it has been shown that electrons from a neutral diatomic molecule ionized by a low-frequency, few-cycle, linearly polarized laser pulse are roughly twice as likely be ionized from the downfield than the upfield atom when the molecule is tilted with respect to the laser polarization [PRL 127 213201 (2021)]. However, the analysis used to draw this conclusion assumed the pulse’s carrier envelope phase (CEP) to be zero. Given experimentalists' limited control over CEP and its dramatic effect on electron momenta after ionization, it is desirable to see what effect CEP plays in determining the ionization site. In this poster, we employ Quantum Trajectory Monte Carlo (QTMC) techniques to simulate strong-field ionization and electron propagation from neutral N2 using an intense 6-cycle laser pulse with various CEP values. Comparing simulated electron momentum distributions to experimental data, the ratio of down-to-upfield ions remains roughly 2:1 regardless of CEP, bolstering previous conclusions. |
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F01.00025: Keldysh theory at arbituary photon energies and a multiphoton perspective on tunnel ionization Spencer R Walker, Bejan Ghomashi, Andreas Becker We have generalized the Keldysh amplitude for strong field ionization in atoms from the long wavelength tunneling regime to the short wavelength regime (down to soft x-rays) to provide a nearly analytic ionization model (for short range potentials). Comparison with numerical results based on simulations of the time-dependent Schrodinger equation show that the model is valid at arbitrary photon energies. In the model we discard the saddle point approximation and evaluate the time-integrals analytically. We will discuss how this model is both useful to predict results in an experiment and give a multiphoton perspective on the transition from multiphoton ionization to tunnel ionization. We include Coulomb corrections in limiting cases and describe difficulties encountered in the multiphoton regime. |
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F01.00026: QUANTUM INFORMATION SCIENCE
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F01.00027: Spectral kissing and its dynamical consequences in the squeezed Kerr-nonlinear oscillator Jorge Chavez, Talia Lezama, Rodrigo G Cortinas, Jayameenakshi Venkatraman, Michel H Devoret, Victor S Batista, Francisco Pérez-Bernal, Lea F Santos Transmon qubits are the predominant element in circuit-based quantum information processing due to their controllability and ease of engineering implementation. But more than qubits, transmons are multilevel nonlinear oscillators that can be employed in the discovery of new fundamental physics. Here, they are explored as simulators of excited state quantum phase transitions (ESQPTs), which are generalizations of quantum phase transitions to excited states. We show that the coalescence of pairs of adjacent energy levels (spectral kissing) recently observed with a squeezed Kerr oscillator [arXiv:2209.03934] is an ESQPT precursor. The classical limit of this system explains the origin of the quantum critical point and its consequences for the quantum dynamics, which includes both the fast scrambling of quantum information, characterized by the exponential growth of out-oftime-ordered correlators, and the slow evolution of the survival probability at initial times, caused by the localization of the energy eigenstates at the vicinity of the ESQPT. These signatures of ESQPT in the spectrum and in the quantum dynamics are simultaneously within reach for current superconducting circuits experiments. |
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F01.00028: Inexpensive Quadrupole Traps for Teaching Undergraduates Isaac J Fouch, Robert E Thomas, Maxwell F Parsons, Boris Blinov Trapped ions are a promising candidate for qubits with demonstrated low error rates and options for scalable architectures. With the growth of quantum information science in academia and industry, there is a need for inexpensive, scalable educational labs to introduce students to concepts in quantum computing. To fill this need, we developed a reproducible lab for physics and engineering students. The lab demonstrates key concepts in ion trapping. The lab consists of two, independent quadrupole traps: a four-rod trap and a planar five-rail trap. To reduce cost and complexity, we trap charged particles with 25 μm and 50 μm diameter. The particles are trapped in air, at atmospheric pressure. Due to the damping forces provided by this background gas, the trapped particles are easy to control. We demonstrate several possible experiments with these traps, including controlling the number of particles trapped through voltage modulation at a constant frequency, studying the phase transition between one- and two-dimensional Coulomb crystals, exploring micromotion compensation, observing two- and three-particle secular modes, and demonstrating particle shuttling along the trapping axis of the planar trap. |
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F01.00029: Noise-resistant quantum memory enabled by Hamiltonian engineering Lei Jing, Hui Tang, Peng Du, Wenxian Zhang The mesoscopic nuclear spin ensemble in quantum dots, which consists of 104 to 106 nuclear spins and has a coherence time of up to milliseconds, is a promising candidate for a fast and scalable quantum memory. Coherently transferring the electron spin state to the collective nuclear spin state requires polarization of the nuclear spin ensemble. Nuclear spin noise can obstruct the transfer process and lower transfer fidelity especially at low nuclear polarization. Here we propose a new protocol for performing noise-resisted quantum state transfer by employing Hamiltonian engineering. By decoupling the nuclear spin noise from the electron with a sequence of pulses, while maintaining the necessary flip-flop interaction, our protocol guarantees high fidelity quantum state transfer at much lower nuclear polarizations. A numerical simulation that we conducted shows a fidelity over 80% can be reached as nuclear polarization drops to as low as 30%. This Hamiltonian engineering methods may also be helpful for future explorations in quantum memory and DNP in other systems such as NV color centers, doped-ion crystals and atomic ensembles. |
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F01.00030: Learned potentials for bosonic matter wave manipulation Katarzyna Krzyzanowska, Tyler Volkoff, Malcolm G Boshier, Andrew T Sornborger An important capability recently developed in the field of variational quantum algorithms (VQAs) is the learning of a target unitary operation using a parameterized quantum circuit, so-called quantum-assisted quantum compilation (QAQC). In the context of discrete or continuous-variable quantum systems, the QAQC procedure allows to encode a target unitary in a depth-optimal or, more generally, resource-optimal circuit. In this work, we extend the concept of QAQC to bosonic systems, specifically for experiments exploiting the matter-wave nature of Bose-Einstein Condensates (BEC) trapped in reconfigurable optical potentials. In this case, what would be considered a quantum algorithm for a discrete quantum system becomes an experimental protocol for a BEC system. The VQA for QAQC in our BEC setting involves minimization of a cost function, which quantifies the distinguishability of BEC states acted upon by either the target or parameterized unitary. |
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F01.00031: Out-of-Time-Order-Correlator in van der Waals potentials Hui Li, Eli J Halperin, Reuben R Wang, John L Bohn Out-of-time-order correlator (OTOC) is one of the dynamical quantities used to quantify the quantum-to-classical correspondence. The OTOC is expected to grow exponentially at early time in chaotic systems, characteristic of a Lyapunov exponent. However, exponential growth can also occur for integrable systems. Here we present the OTOC for realistic diatomic molecular potentials in one degree of freedom. The results show that the OTOC can grow exponentially near the dissociation energy of the potential, and this dynamics is tied to the classical dynamics of the atoms at the outer classical turning point. These results may serve to guide and interpret dynamical chaos in more complex molecules. |
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F01.00032: Completely Ergodic Quantum Dynamics in Quasiperiodically Driven Systems Saúl Pilatowsky-Cameo, Ceren B Dag, Wen Wei Ho, Soonwon Choi The ergodicity of quantum dynamics with time-independent (or time-periodic) Hamiltonians is often defined through certain statistical properties of (quasi-)energy eigenstates or energies. Such a definition, however, cannot be applied for general time-dependent Hamiltonian dynamics for which eigenstates and eigenenergies may not exist. In this work, we present a new, stronger form of quantum ergodicity, called complete quantum ergodicity (CQE), based on the concept of state design from quantum information theory: CQE requires that the trajectory of any time-evolved wavefunction visits every corner of the Hilbert space uniformly over time. This is a form of ergodicity which is more in line with traditional notions of ergodicity in dynamical systems, in that the time-averaging of a trajectory reproduces an averaging over the space that it moves in. While CQE cannot be attained by time-independent (-periodic) time due to (quasi-)energy conservation, we present explicit solvable examples of CQE achieved by a class of aperiodic, deterministic, and unitary evolution with minimal complexity such as the Fibonacci drive. Using both analytic and numerical techniques, we discuss the implications of our results in the deep thermalization of quantum states and the formation of k-designs in time. |
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F01.00033: Towards an 171Yb atom array in an optical cavity Won Kyu Calvin Sun, Neville Chen, Aakash V, Nathan Zachar, Brett N Merriman, Lintao Li, Yaashnaa Singhal, Healey Kogan, Jacob Covey Neutral atom arrays are a promising platform for quantum information processing. In particular, the 171Yb is an attractive atomic species as an alkaline-earth-like atom with a rich energy level structure and a nuclear spin-½. We plan to expand upon this architecture by incorporating the 171Yb atom array into a dual-wavelength optical cavity. The cavity is designed for 556 and 1390 nm (resonant with the Yb `imaging' and telecom transitions respectively) to realize fast non-destructive mid-circuit readout, e.g., for quantum error correction, as well as an efficient optical interface for quantum communication. In this poster we discuss our progress in building our next-generation experimental setup. |
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F01.00034: Numerical Investigation of the Dynamics and Stability of Electrons in a Paul trap Neha Yadav, Edith Hausten, Qian Yu, Andris Huang, Isabel Sacksteder, Alberto M Alonso, Ralf Schneider, Hartmut Haeffner Trapped electrons holds great promise as platform for an ideal qubit due to their light mass and two-level spin system, that can be manipulated and read using microwave technology. Prior experiments have established trapping electrons in a Paul trap at room temperature for up to 1 second [1]. However, to fully exploit trapped electrons for quantum computing, they must be cooled to a temperature that enables the formation of stable Coulomb crystals within the Paul trap. Here, we present the results of our recent numerical simulations exploring the dynamic stability of trapped electrons in the trap, predicting that a minimum temperature of 400 milliKelvin is required to form such stable Coulomb crystals. |
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F01.00035: Monolithic segmented blade ion trap system Roman Zhuravel, Abhishek Menon, Midhuna Duraisamy Suganthi, April Sheffield, Visal So, Mingjian Zhu, Guido Pagano Quadrupole-based traps are versatile tools for AMO research and specifically for the ion-trapping community widely used in quantum computing, simulation, and sensing. Despite the advances of planar chip microfabricated traps, three-dimensional blade traps still offer the advantages of ease of use (simpler controls), eV-deep trapping potentials, robustness to stray fields, larger ion-electrode distance (low heating rates), as well as wider and multi-directional optical access. |
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F01.00036: Two-qubit Quantum Logic Gates for Neutral Atoms Based on the Spin-Flip Blockade Vikas V Buchemmavari, Ivan H Deutsch, Yuan-Yu Jau, Sivaprasad T Omanakuttan The strong dipole-dipole interaction between atoms in Rydberg states has emerged as the standard mechanism to induce entanglement between neutral atom qubits. In these protocols, optical/UV lasers that couple qubit states to Rydberg states are modulated to implement entangling gates. Here we present an alternative protocol to implement entangling gates via Rydberg dressing and the spin-flip blockade. An auxiliary state in the ground-hyperfine-manifold is optically dressed so that it acquires partial Rydberg character. It thus acts as a proxy Rydberg state, with a nonlinear light-shift and longer lifetime than the Rydberg state it is coupled to. Hence, a microwave frequency field coupling a qubit state to this dressed auxiliary state can be modulated to implement entangling gates. Many entangling protocols designed for the optical regime can be imported to this microwave regime. Not only is coherent control more mature for microwave than optical fields, but such control can be made more robust to imperfections, such as thermal motion of the atoms. We study various regimes of operations that can yield high-fidelity two-qubit entangling gates. |
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F01.00037: A quantum computing platform using a 2D array of Cs neutral atom qubits Linipun Phuttitarn, Ravikumar Chinnarasu, Cody Poole, Yunheung Song, Kais Jooya, Jacob Scott, Patrick Eichler, Trent Graham, Mark Saffman We present our recent progress towards quantum computing with a two-dimensional atomic qubit array. Cooled Cs atoms are loaded into a blue-detuned optical lattice constructed from cross-hatched lines. Atomic rearrangement using optical tweezers is used to deterministically load atoms into targeted sites to create defect free atomic arrays. Single-site quantum gates are performed using resonant microwaves and site-selective Stark shifts; controlled-Z gates are performed using two-photon Rydberg excitations. Using this universal gate set, we demonstrate a variety of multi-qubit quantum algorithms. We present results using the variational quantum eigensolver algorithm to estimate ground state energies of the Lipkin Hamiltonian. We will also present implementation of mid-circuit readout of ancilla qubits in a 3x3 2D array of Cs atoms based on shelving data qubits into a dark hyperfine manifold and progress towards ancilla recooling and resetting. |
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F01.00038: The Quantum Scientific Computing Open User Testbed (QSCOUT) Matthew N Chow, Melissa C Revelle, Ashlyn D Burch, Joshua D Goldberg, Megan K Ivory, Andrew J Landahl, Daniel S Lobser, Benjamin C Morrison, Kenneth Rudinger, Antonio E Russo, Brandon P Ruzic, Jay W Van Der Wall, Christopher G Yale, Susan M Clark While remote access to quantum computers is increasingly available, in many of these cases the necessary tools to fully specify and characterize the behavior of the hardware itself remains inaccessible. The Quantum Scientific Computing Open User Testbed (QSCOUT) is a ytterbium-ion based system designed and operated with the objectives of full transparency and low-level control to address the potential of near term quantum hardware. QSCOUT's user-accessible software stack includes custom assembly and waveform generation languages. This enables users to both fully specify the native operations and run novel quantum gates via custom pulse sequences. Further, users interact directly with the Sandia scientists who operate the machine, allowing them to realize the full potential and flexibility of the device. This poster highlights current experiment capabilities (including high-fidelity individual addressing and fully parameterized two-qubit gates), selected user results, and plans for future directions and collaboration opportunities with QSCOUT. |
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F01.00039: Floquet-engineered degeneracies for holonomic gates are fragile Logan W Cooke, Arina Tashchilina, Mason Protter, Joseph Lindon, Tian Ooi, Frank Marsiglio, Joseph Maciejko, Lindsay J LeBlanc Holonomic gates, which rely on non-Abelian geometric phases in degenerate systems, are commonly thought to be robust to various errors. Several recent proposals have introduced a new approach to universal holonomic quantum computing which uses Floquet engineering to obtain the required degeneracy, and this approach seems to promise the same robustness. We demonstrate these gates on the spin states of a rubidium-87 BEC, where fast modulations produce a degeneracy between the spins permitting their holonomic evolution. The presence of external noise perturbs this degeneracy, necessitating a more generalized treatment of the system's evolution which includes dynamical contributions to the phase. We compare the evolution of this system to a more general theory, showing the newly-acquired degeneracy is not robust. |
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F01.00040: Towards a Scalable quantum computing platform with trapped electrons in Paul Traps Madhav Dhital, Zijue Luo, Shirish Pathak, Fan Lu, Qian Yu, Alberto M Alonso, neha yadav, Isabel Sacksteder, Shuqi Xu, Xiaoxing Xia, Abhinav Parakh, Kristin M Beck, Juergen Biener, Dietrich Leibfried, Hartmut Haeffner, Boerge Hemmerling We are working towards realizing a scalable quantum computing platform using spins of electrons as qubits. Among the different physical implementations, trapped electrons offer high clock speeds in the GHz regime and are expected to offer coherence times on the minute scale, similar to qubits in trapped ions. Moreover, the electron's simple two-level structure avoids information leakage to other states. Our recent feasibility study of a quantum processor based on trapped electrons shows that error rates of less than 1e-4 in two-qubit gate operations are theoretically achievable. |
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F01.00041: Quantum networking with trapped 88Sr+ and 43Ca+ ions Peter Drmota, David P Nadlinger, bethan C nichol, Dougal Main, Ellis M Ainley, Chris J Ballance, Raghavendra Srinivas, Gabriel Araneda, David M Lucas Quantum networks are essential for future applications in distributed quantum computing, cryptography, and metrology. |
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F01.00042: Design of a 50-qubit ion-trap demonstrator apparatus and chip Timko Dubielzig, Tobias Pootz, Lukas Kilzer, Celeste Torkzaban, Florian Ungerechts, Rodrigo Munoz, Brigitte Kaune, Teresa Meiners, Christian Ospelkaus The QVLS-Q1 research consortium is comitted to building a 50-qubit ion-trap based quantum computer. We present work towards the realization of this goal. We have designed and started assembly work on a demonstrator apparatus, based on previous work [1]. A cryogenic apparatus with 300 dc-, nine radiofrequency- and nine optical interconnects. The apparatus will house a multi-layer surface electrode ion trap-chip, which is designed and fabricated in house. The trap-chip consists of an ion-shuttling junction [2], ion-storage registers, a readout register and a computation zone, where near-field microwave gates will be applied [3]. We present the apparatus and chip design works and current progress. |
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F01.00043: Optimal, robust, arbitrary, parallel single-qubit unitaries with limited individual control Wenjie Gong, Soonwon Choi The ability to robustly implement different single-qubit unitaries in parallel is crucial for scalable quantum information processing. However, local single-qubit manipulations are difficult to engineer in existing quantum platforms such as neutral atom arrays, where qubits are addressed by a global laser field. Here, we construct simple, optimal-length pulse sequences for the parallel realization of independent, arbitrary single-qubit unitaries under two restricted forms of individual control: (1) when each qubit can be individually detuned from resonance, and (2) when each qubit can be subject to a different laser phase. We further devise optimal-length modifications of these pulse sequences that feature robustness against amplitude error, a dominant source of imperfection arising from field inhomogeneity and laser fluctuations. These results provide a path towards achieving universal quantum computation on near-term technology. |
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F01.00044: Spin-transparent storage rings as a quantum computing architecture Matt Grau, Vasiliy S Morozov, Riad S Suleiman Charged particles in spin-transparent storage rings can exhibit long spin-coherence times of up to several hours, making them an interesting but untested prospect for quantum computing. Several of the critical requirements of quantum computing have been experimentally achieved: State-preparation is done by shining polarized light on a photocathode, emitting spin-polarized electrons. Single-qubit gates are performed by the arbitrary polarization rotations implemented by the pulsed magnetic field of a solenoid. Finally, readout of the spin-polarization state is done using a Mott-polarimeter. The remaining necessary ingredient for universal quantum computing is a way to perform two-qubit gates. While performing two-qubit operations on particles in the storage ring appears challenging, we have identified a possible scheme to load electrons with entangled spins by generating them with an entangled train of light pulses on the photocathode. These spin-entangled electrons could then be used as a resource in a measurement-based scheme to perform multi-qubit gates in the storage ring. |
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F01.00045: A quantum register using collective excitations in an atomic ensemble without a Rydberg blockade Elisha B Haber, Zekai Chen, Nicholas P Bigelow A qubit made up of an ensemble of atoms is attractive due to its resistance to atom losses, and many proposals to realize such a qubit are based on the Rydberg blockade effect. Here, we instead consider an experimentally feasible protocol to coherently load a 3D spin-dependent optical lattice from a spatially overlapping Bose--Einstein condensate. Identifying each lattice site as a qubit, with an empty or filled site as the qubit basis, we discuss how high-fidelity single-qubit operations, two-qubit gates between arbitrary pairs of qubits, and nondestructive measurements could be performed. In this setup, the effect of atom losses has been mitigated, and at no point do we need to remove the atoms from the computational basis in the ground state manifold, both of which can be significant sources of decoherence in other types of atomic qubits. Finally, we explore how one could also use the condensate as either a spectator to continuously measure and calibrate the laser and magnetic fields controlling the qubits, or as a tool to address individual qubits in the lattice by imprinting topological defects in the condensate without the typical need for mutliple tightly focused laser beams. |
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F01.00046: Progress toward a quantum processor testbed based on nitrogen-vacancy centers in diamond Asher Han, Willow Strey, Enrique Garcia, Bethany Matthews, Tommy Nguyen, Ethan Hansen, Christian Pederson, Nicholas S Yama, Maxwell F Parsons, Kai-Mei C Fu The negatively-charged nitrogen-vacancy (NV) center in diamond, consisting of a substitutional nitrogen atom and an adjacent vacancy defect, can provide a platform for quantum registers of at least 10 qubits [1]. The NV center has many useful properties such as optical addressability and long spin-coherence times even at room temperature. We describe a new NV-based quantum computing testbed at the University of Washington. A solid immersion lens is fabricated in the diamond above a single NV center for enhanced light collection with a cryogenic confocal microscope, allowing for single-shot readout of the electronic spin state. We use a combination of two permanent magnets, one fixed magnet inside the cryostat and another adjustable magnet outside the cryostat for precise alignment of the magnetic field to the NV-axis. Finally, we describe the design and fabrication of a radio-frequency antenna on the diamond substrate to optimize couplings to the NV-center electronic spin and nearby nuclear spins. The testbed will be used to implement quantum protocols and small-scale quantum algorithms for both pedagogical and research purposes. |
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F01.00047: Coherence Preserving Ion-loss Error-detection Protocol Darian M Hartsell, Vikram Sandhu, Craig R Clark, Kenton R Brown In a system of trapped ions, ion loss is inevitable due to collisions or chemistry with background gasses. To minimize the impact of these loss errors on a quantum algorithm, it would be beneficial to detect them without decohering the quantum state of any computational ions. For this purpose, we have developed an error-detection protocol which merges and separates an ancilla and a computational ion. Subsequent detection of fluorescence from the ancilla indicates that both ions remain in the trap, while absence of fluorescence indicates that at least one of the ions has been lost. We experimentally demonstrate that the protocol does not significantly heat or decohere the computational ion. This protocol could be useful for post-processing of data or could be integrated actively into error correction. |
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F01.00048: Reduced Crosstalk Errors during the Mølmer–Sørensen Gate through Choice of Vibrational Mode Vikram Kashyap, Brant B Bowers, Ritika Anandwade, Sara Mouradian Laser crosstalk is a major obstacle to the scaling of trapped ion quantum computers. Multi-qubit gates couple the ions' electronic states to a shared vibrational mode, often the center-of-mass (COM) mode where every ion has the same coupling to the mode. When crosstalk is present during the operation of the Mølmer–Sørensen (MS) entangling gate, the ions that are being targeted for entanglement become partially entangled with their neighbors, reducing the fidelity of the final state. We present numerical and analytical results showing that the final state fidelity can be increased using a non-COM vibrational mode for which the neighboring ions have lower coupling to the vibrational mode than the targeted ions. Though the efficacy of this strategy is highly dependent on the particular pair of ions being entangled, we find experimentally relevant scenarios in which fidelity can be increased from below 40% to above 90% for pairwise entanglement in a chain of 6 ions. We will present a method for quickly determining which vibrational mode of an ion string is most resilient to laser crosstalk when applying the MS gate on a given pair of ions. We are currently investigating ways to tailor vibrational modes to further improve the fidelity of multi-qubit gates in the presence of crosstalk. |
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F01.00049: Spectroscopy and modeling of Yb Rydberg states for neutral atom quantum computing Yiyi Li, Michael Peper, Daniel Y Knapp, Jeff D Thompson Alkaline earth atoms such as Yb are very promising for quantum computing and simulation. Precise knowledge of their Rydberg states is crucial to understand and predict their interactions, lifetimes and decay pathways. In this poster, we will present precision measurements of Yb Rydberg states using laser and microwave spectroscopy in an atomic beam apparatus. We will also present ongoing work to develop a comprehensive MQDT model for both 174Yb and 171Yb, including a calculation of interaction strengths and lifetimes, and a comparison with measured values in an optical tweezer apparatus. |
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F01.00050: Mid-circuit measurements and entanglement in tweezer arrays of nuclear spin qubits Joanna W Lis, Aruku Senoo, William F McGrew, Alec Jenkins, Adam M Kaufman Neutral atoms in optical tweezers are a promising quantum science architecture, owing to scalability, programmability and single-site readout. A thriving frontier seeks to expand these capabilities, drawing on the unique properties of more complex atoms. One of them is ytterbium 171: its nuclear spin ½ decoupled from electrons is a native qubit robust to decoherence, while its two valence electrons give rise to narrow-linewidth transitions used for preparation of low-entropy atom arrays and qubit manipulation. |
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F01.00051: Metastable Qubit Operations in 171Yb+ Patrick J McMillin, Thomas Dellaert, Hassan Farhat, Wesley C Campbell The metastable ("m-type") qubit defined on the zero-field hyperfine clock states in the long-lived 2F7/20 manifold in 171Yb+ gives a promising pathway to low cross-talk, high fidelity multi-qubit operations using the same ion species via the recently proposed "omg blueprint'' for atomic quantum processing. We describe heralded state preparation, single qubit operations, and state measurement in the m-type qubit, achieving a SPAM infidelity of 4+3-2 X 10-4 and provide empirical, quantitative limits on the effect of direct illumination by ground state ("g-type'') qubit light. |
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F01.00052: Experimental progress towards quantum control of strontium qudits Eric J Meier, Leonardo de Melo, Hari P Lamsal, Thomas M Bersano, Enrique A Segura Carrillo, Andrew K Harter, Sivaprasad T Omanakuttan, Anupam Mitra, Ivan H Deutsch, Malcolm G Boshier, Michael J Martin Neutral atom quantum computing leveraging Rydberg physics has made some significant advances recently. Successes with long coherence times, fast entangling gates, and nuclear spin qubits have renewed interest in this sub-field of quantum information science. In this vein, we report on our ongoing experimental efforts to realize a strontium Rydberg system controlled with a novel quantum control scheme. We will present our progress on the apparatus and our techniques for transporting and trapping cold strontium atoms using active optics. We will also detail our novel technique for quantum control using the 10-dimensional nuclear spin state space of strontium 87. |
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F01.00053: Multi-scale architecture for fast optical addressing and control of large scale qubit arrays Eunji Oh, Trent Graham, Mark Saffman The use of spatial light modulators(SLM) for site-selective quantum state control has been limited due to slow transition times preventing rapid, consecutive quantum gates. We present a hybrid architecture consisting of a fast deflector and a spatial light modulator which allows rapid site-selective control of the quantum state of qubits in a large 2D lattice. We split the spatial light modulator into multiple segments and switch between them using a fast deflector. With this proposed setup, the average time increment between scanner transitions is substantially reduced, increasing the number of gates that can be performed within a single spatial light modulator full frame setting. We analyze the performance of this device in two different configurations: in configuration 1, each segment of the spatial light modulator addresses the full qubit lattice; in configuration 2, each segment of the spatial light modulator addresses a sub-array, and an additional fast deflector positions the sub-array with respect to the full qubit lattice. With these hybrid scanners, we calculate qubit addressing rates that are tens to hundreds of times faster than using a spatial light modulator alone. Furthermore, we show that these scanners can also be implemented with a simple hologram generation method without requiring iterative algorithms. |
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F01.00054: Spin squeezed GKP codes for quantum error correction in atomic ensembles Sivaprasad T Omanakuttan, Tyler Volkoff GKP codes encode a qubit in displaced phase space combs of a continuous-variable (CV) quantum system and are useful for correcting a variety of high-weight photonic errors. Here we propose atomic ensemble analogs of the single-mode CV GKP code by using the quantum central limit theorem to pull back the phase space structure of a CV system to the compact phase space of a quantum spin system. We study the optimal recovery performance of these codes under error channels described by stochastic relaxation and isotropic ballistic dephasing processes using the diversity combining approach for calculating channel fidelity. We find that the spin GKP codes outperform other spin system codes such as cat codes or binomial codes. Our spin GKP codes based on the two-axis countertwisting interaction and superpositions of SU(2) coherent states are direct spin analogs of the finite-energy CV GKP codes, whereas our codes based on one-axis twisting do not yet have well-studied CV analogs. A state preparation of the spin GKP codes is proposed which uses the linear combination of unitaries method, applicable to both the CV and spin GKP settings. Finally, we discuss a fault-tolerant approximate gate set for quantum computing with spin GKP-encoded qubits, obtained by translating gates from the CV GKP setting using the quantum central limit theorem. |
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F01.00055: Geometric quantum adiabatic methods for bond dissociation energy calculation Ruiren Shi, Tzu-Chieh Wei, Jesus Perez Rios In this work, by obtaining eigenstates and eigenvalues of a molecule's Hamiltonian under different geometry configuration, we are able to apply a quantum algorithm based on adiabatic evolution to calculate the dissociation energy of this molecule. In particular, we use the geometric quantum adiabatic evolution (GeoQAE)[1]. However, it has not been proved effective regarding molecules with more than 12 electrons. In this project, we make use of a tensor product matrix approximation[2] to GeoQAE so that adiabatic evolution can be achieved even when the Hamiltonian is gigantic. As a result, we can accurately calculate the bond dissociation energy of complex molecules. |
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F01.00056: A scalable, modular, fault-tolerant quantum computer based on Rydberg arrays and optical cavities Josiah J Sinclair, Joshua Ramette, Nikolas P Breuckmann, Vladan Vuletic One of the most promising routes toward scalable quantum computing is a modular approach. We show that distinct surface code patches can be connected in a fault-tolerant manner even in the presence of substantial noise along their connecting interface. We quantify analytically and numerically the combined effect of errors across the interface and bulk. We show that the system can tolerate 14 times higher noise at the interface than the bulk, with only a small effect on the code's threshold and sub-threshold behavior, reaching threshold with ~1% bulk errors and ~10% interface errors. We apply these results to the specific case of programmable Rydberg arrays, proposing a novel architecture for quantum computing which is scalable, modular, and fault-tolerant. Differing from previous modular approaches, our modules are large, containing hundreds to thousands of qubits forming surface code patches linked together using only modest quality Bell pairs. To analyze the feasibility of our architecture, we further develop detailed workflows and give quantitative performance estimates showing that a single optical cavity of modest quality allows Bell pair distribution fast enough to realize 10 kHz surface codes, much faster than current coherence times. |
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F01.00057: Realization of Scalable Cirac-Zoller Multi-Qubit Gates Ke Sun, Chao Fang, Jungsang Kim, Ye Wang The universality theorem in quantum computing states that any quantum computational task can be decomposed into a finite set of logic gates operating on one and two qubits [1]. The Cirac-Zoller gate is a protocol for realizing native multi-qubit controlled-Z gate utilizing spin interactions mediated by Coulomb-coupled collective motion of an ion crystal [2]. Despite being outperformed by the more popular Molmer-Sorensen (MS) gate at implementing the two-qubit controlled-NOT (CNOT) gate due to its more challenging technical requirements, the Cirac-Zoller gate scheme scales much more efficiently with the number of qubits. We demonstrate the Cirac-Zoller three-qubit and four-qubit quantum Toffoli gates in a five-ion chain with higher fidelities than previous results using trapped ions. We also report the first experimental realization of a five-qubit Toffoli gate. |
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F01.00058: Towards entangling gates between bosonic qubits in trapped ions Martin Wagener, Stephan Welte, Moritz Fontboté Schmidt, Ivan Rojkov, Edgar Brucke, Hendrik Timme, Ralf Berner, Matteo Marinelli, Ilia Sergachev, Florentin Reiter, Daniel Kienzler, Jonathan Home Encoding quantum information in a harmonic oscillator offers a resource efficient method for quantum error correction, compared to the use of multiple two-level systems. The Gottesman-Kitaev-Preskill (GKP) encoding [1] is particularly promising and has recently been realized in both trapped ions [2, 3] and superconducting microwave cavities [4]. |
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F01.00059: Gate operations in sympathetically-cooled Yb+ chains Tianyi Wang, Andrew Van Horn, Or Katz, Jungsang Kim, Marko Cetina Preserving high gate fidelity while maintaining qubit connectivity is a major goal in scaling up quantum computers and simulators. In systems based on long chains of trapped ions, this is challenging due to heating via the coupling of ions to noisy electric fields, especially in the weakly-confined axial direction. In systems based on 171Yb+, this challenge can be countered by sympathetic cooling using 172Yb+ coolants [1]. |
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F01.00060: Generation of bottle beam array by spatial light modulator for atom-based quantum computing Tsai-Ni Wang, Ya-Fen Hsiao, Ying-Cheng Chen We generate two-dimensional bottle beam arrays for laser trapping of atoms in the ground and Rydberg states. A dipole-trap laser beam is diffracted by a phase spatial light modulator imprinted with a phase hologram to generate two dimensional arrays of bottle beam of arbitrary geometries. We found that the phase hologram calculated by the Gerchberg-Saxton algorithm, typically used in cold atom community, may cause a certain fraction of defects in the generated bottle beams, depending on the phase range of the initial guess and the array geometry. We have developed a modified optimal beam splitting algorithm to calculate the phase hologram and no defects are found in all calculated array geometries. We demonstrate the generation of bottle beam arrays of various geometries, which may open appealing applications in quantum information processing and simulation based on Rydberg atoms. |
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F01.00061: DEGENERATE GASES AND MANY-BODY PHYSICS
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F01.00062: In situ imaging and manipulation of Cs-Li Bose-Fermi mixture Henry Ando, Geyue Cai, Krutik S Patel, Michael Rautenberg, Sarah McCusker, Cheng Chin Quantum degenerate mixtures of bosonic and fermionic atoms are a powerful platform for quantum simulation, as well as rich physical systems in their own right. This poster reports on our investigation of cesium Bose-Einstein condensate immersed in a lithium degenerate Fermi gas. Based on in situ imaging and optical potential projection, we observe intriguing sound propagation dynamics in the mixture across an interspecies Feshbach resonance. Surprisingly, the sound mode persists across the resonance. Imaging the two species in each mixture, we investigate the beyond-mean-field correlations of bosons and fermions induced by interspecies interactions. |
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F01.00063: Many-body polarization and topological phases of the Rice-Mele-Hubbard model Julius Bohm, Dennis Breu, Michael Fleischhauer The many-body polarization introduced by Resta [1] has been shown to be a powerful tool to distinguish topological phases of one-dimensional lattice models of fermions in the absence or presence of interactions |
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F01.00064: NASA’s Earth Orbiting Cold Atom Lab Sofia Botsi The Cold Atom Lab (CAL) launched to the International Space Station (ISS) in May 2018, and has been operating since that time as the world’s first multi-user facility for the study of ultra-cold quantum gases in space. The unique microgravity environment of the ISS is utilized with CAL by a national group of principal investigators to achieve sub-nanokelvin temperature gases, to study and utilize their quantum properties in an environment free from the perturbing force of gravity, and to observe and interact with these gases in the essentially limitless free-fall of orbit. In addition to the toolbox of capabilities originally built into CAL, an upgrade in 2020 enabled the study of atom interferometry in orbit, a 2021 upgrade and repair facilitated investigations of the interactions between mixtures of 87Rb, 39K, and 41K and dual species (87Rb & 39,41K) atom interferometry. Planning is ongoing for a near-term upgrade to further enable novel science with ultracold quantum gases in space. This poster discusses the up to date microgravity enabled quantum gas research explored with CAL that has broad applications in fundamental physics and precision measurements. |
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F01.00065: Quantum effects in axion dark matter Vasileios Fragkos, Igor Pikovski, Michael Kopp Axion-like particles (ALP) are promising dark matter candidates. A classical field description is typically employed, motivated by large phase space occupation numbers. Here we show that such a description is accompanied by a quantum effect: squeezing due to gravitational self-interactions. For a typical QCD axion today, the onset of squeezing is reached on microsecond-scales and grows over millennia. Thus within the usual models based on the classical Schrödinger-Poisson equation, a type of Gross-Pitaevskii equation, any viable ALP is nonclassical. We also show that squeezing may be relevant on scales of galactic solitonic cores. Conversely, our results highlight the incompleteness and limitations of the typically employed classical single field description of ALPs. |
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F01.00066: Design, Development, and Alignment of a 2D Magneto-Optical Trap Dustin Greenwood, Judith Gonzalez Sorribes, Danielle Smith, Maren E Mossman Magneto-optical traps (MOTs) are essential to attain fast and efficient loading of atoms with reduced energies and temperatures. For ultracold atomic physics experiments, the MOT is at the heart of an apparatus, setting the stage for the first steps of cooling. In this work, we present a brief background on MOT physics and report on the progress of our lab at University of San Diego to produce a 2-dimensional MOT, starting with the laser system design, optics platform and coil design, and initial calibrations for the system. |
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F01.00067: Scripted Control System for Applications in Quantum Technology Andrew Jockelle, Rachelle Childers, Matthew Gloriani, Joaquin de Cabanyes Galindo, Christian Picos, Blake Lindemeyer, Maren E Mossman In this work, we describe the development of a scripted control system for applications in quantum technology, specifically to ultracold atom experiments at a primarily undergraduate institution. Our focus is to build hardware for DAC and TTL control, develop a software interface for autonomous hardware-timed control, further our understanding of bit management and manipulation, and implement and test the integrated control system in an R&D setting. This project brings together physics and engineering undergraduate students in a collaborative environment, developing skills with automation programming and time-dependent control systems for quantum technologies, building and developing time-keeping electronics for D I/O control, to further develop skills in circuit design and development in an R&D setting. In this poster, we will present details of the control system, as well as current status and future applications of the work. |
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F01.00068: Tunneling dynamics of small two-component Fermi system Kevin Mack-Fisher, Doerte Blume Tunneling is an inherently quantum mechanical process. Interactions between particles can speed the single-particle tunneling dynamics up or slow it down; they can also trigger correlated tunneling of pairs or clusters. We use high performance computing to implement a trapezoidal splitting method that allows us to solve the three-particle time-dependent Schrodinger equation for a time-dependent potential. We first use imaginary time-evolution to prepare the system in an eigenstate of the Hamiltonian at the initial time. We subsequently use real time-evolution to time evolve the initial state. Throughout the real time-evolution, we monitor the flux in configuration space to study the probability of finding zero, one, two, or three particles in the trap and extract tunneling rates. We will show preliminary results. |
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F01.00069: Progress Towards Few-Body Measurements in Microgravity Colby Schimelfenig, Jose P D'Incao, Maren E Mossman, Peter W Engels In this poster, we discuss progress towards the measurement of Efimov physics using NASA's Cold Atom Lab (CAL), a quantum gas experiment installed onboard the International Space Station (ISS). Efimov physics predicts the appearance of an infinite series of cascading few-body bound states (e.g., trimers and tetramers) in the vicinity of a Feshbach resonance, where the energy levels of these states are separated by a universal scaling constant. However, due to the large sizes and weak binding energies of these fragile states, measuring beyond the lowest lying state has proven difficult, requiring systems capable of generating ultra-dilute and ultra-cold quantum gases. CAL is well suited for such measurements. Built and operated by the Jet Propulsion Laboratory (JPL, Pasadena), CAL is a unique quantum gas user facility dedicated to the creation and manipulation of ultracold atoms aboard the ISS. In the continuous presence of microgravity, CAL is able to relax magnetic trapping parameters far beyond what is possible in ground-based studies, allowing atoms to enter the extremely cold and dilute regime needed to probe Efimov physics. Here, we will present our current progress towards state preparation of potassium-39 atoms needed to begin measurements of Efimov physics and theoretical simulations. Future measurements in this project will provide essential benchmark data for refining existing theoretical model calculations and elucidate complex topics in quantum few-body dynamics. |
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F01.00070: Characterization of an ultrahigh vacuum system for degenerate quantum gases Danielle Smith, Judith Gonzalez Sorribes, Maren E Mossman Tabletop ultrahigh vacuum (UHV) systems are a necessary laboratory environment for the creation and manipulation of ultracold degenerate quantum gases. At the University of San Diego, a primarily undergraduate institution, we have assembled such a system and are in the process of moving toward initial stages of cooling using a 2D to 3D magneto-optical trap setup. In this poster, we will present details of our vacuum setup, including capacitance, pump preparation and maintenance, leak testing, and bakeout procedures, as well as next steps for our ultracold atom system. |
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F01.00071: Mean-field vs. quantum decoherence of 7Li matter-wave breathers Ricardo Espinoza, Yi Jin, Sehyun Park, Randall G Hulet, Maxim Olchanyi N-soliton breathers are high-order soliton solutions of the attractive nonlinear Schroedinger equation (NLSE). They may be formed by suddenly quenching the interaction strength of a fundamental soliton by certain integer factors.1,2 The required control of the interaction strength is provided by a Feshbach resonance in a Bose-Einstein condensate of 7Li confined in quasi-1D. As mean-field (MF) solutions of an integrable equation, pure 1D breathers are localized in space and oscillate in time without dispersion. In reality, breathers are susceptible to decoherence due to both MF3 and quantum4,5 effects. In this experiment, we report the MF decoherence of 2-soliton breathers due to three-body recombination. These findings impose an experimental limit on the atom density below which quantum effects can be observed. We present results of our efforts to observe decoherence due to quantum fluctuations of the relative parameters of 2-soliton breathers.6 |
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F01.00072: Potassium condensates in optical tweezers Jeremy Estes, Jared E Pagett, Madeleine Bow Jun Leibovitch, Andrew Jayich, David M Weld We present progress on the construction of a potassium based neutral cold atom machine which will combine the high precision spatial control of optical tweezers with the creation of degenerate quantum gasses. The experiment aims to condition the coherent Raman transfer of spin population in small Bose-Einstein Condensates (BECs) on the presence of Rydberg excitations, and leverages polarization contrast imaging to non-destructively image the BECs. With these capabilities we aim to explore fundamental new directions in thermodynamics, monitored dynamics, and quantum interactive dynamics. We also present progress on a measurement of a magic trapping wavelength for Potassium 39 near 1227 nm. |
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F01.00073: Measuring Rotation in a Bose-Einstein Condensate with Phonon Interferometry Charles W Woffinden, Andrew J Groszek, Guillaume Gauthier, Bradley J Mommers, Micheal W. J. Bromley, Simon A Haine, Halina Rubinsztein-Dunlop, Matthew J Davis, Mark Baker Inertial sensors are critical in navigation systems but are typically reliant on the GPS network. New classes of inertial sensors that exploit quantum effects promise to give enhanced absolute measurements of motion in GPS-denied environments such as in space or underwater. In this work, we demonstrate the use of a ring-shaped Bose-Einstein condensate (BEC) as a rotation sensor by imprinting phase [1] to create low-energy phonon standing wave excitations and then observing the precession of the nodes and antinodes of the excitation in response to rotation. We observe a high-quality factor of up to Q = 27 for the imprinted excitations which, when combined with a relatively large 100 μm ring diameter, realizes a much higher sensitivity than has been demonstrated previously [2,3]. Persistent currents are imprinted into the ring, mimicking slow rotation rates and demonstrating the measurement utility of the scheme. Experimental results are compared with simulations using finite temperature stochastic projected Gross Pitaevskii equation (SPGPE) that reveal the dominant damping mechanisms, furthermore demonstrating the parameter space where the damping can be minimized. |
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F01.00074: Towards a continuous atom laser Junyu He, Noé Grenier, Rodrigo Gonzalez Escudero, ChunChia Chen, Jiri Minar, Shayne Bennetts, Benjamin Pasquiou, Florian Schreck A continuous atom laser would be a promising source for quantum sensing, providing a high-flux, low-divergence beam while avoiding measurement dead time. We plan to outcouple such a beam from a Bose-Einstein condensate that we can continuously sustain. Our approach sends a Sr beam from an oven through a sequence of spatially separated laser cooling stages till the atoms accumulate in a protected area where they condense. Our next steps will be to enhance the purity of the BEC and to outcouple a continuous atom laser beam using a three-photon transfer to an untrapped state. |
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F01.00075: A versatile platform of dipolar Er BECs in an arbitrary potential Yifei He, Ziting Chen, Mingchen Huang, Mithilesh K Parit, Haoting Zhen, Gyu-Boong Jo Magnetic atoms such as dysprosium and erbium have attracted significant attention due to the long range and anisotropic dipole-dipole interaction arising from the large magnetic moment. In this poster, we report the latest upgrade of our versatile apparatus towards a dipolar Bose-Einstein condensate (BEC) in an arbitrary programmable potential. Efficient production of dipolar BECs of $^{168}$Er and $^{166}$Er benefits from two-stage slowing followed by optical evaporative cooling. A dipolar BEC will then be adiabatically loaded into arbitrary potentials created by a spatial light modulator (SLM) with a high-resolution imaging system. We highlight how the dipolar system interplays with the special trap geometries. |
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F01.00076: An apparatus for a quantum-degenerate mixture of Er and Li atoms Jasmine Kalia, Jared Rivera, Ruoyi Yin, Richard J Fletcher We present progress towards the creation of a quantum-degenerate mixture of erbium and lithium atoms. The species are slowed and trapped simultaneously, and the sample is brought to degeneracy inside a nano-textured glass cell. The gas is imaged via a microscope objective (NA = 0.6). This alkali-lanthanide mixture offers exciting new possibilities, including new forms of long-range interactions via phonon exchange, mixed dimensional systems, collective spin physics, topological quantum matter, and few-body phenomena. |
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F01.00077: Quantum Simulation in many-body cavity QED systems Xiangliang Li, Ming Xue, Davide Dreon, Alexander Baumgärtner, Simon E Hertlein, Tobias Donner, Tilman Esslinger Ultracold atoms coupled inside optical cavities have been used as quantum simulation platforms with long-range interatomic interactions. With a transversally pumped atomic ensemble coupled in an optical cavity, the coherent photon scatterings between pump beam and cavity mode effectively generate long-range atom-atom interaction and lead to crystallization of atoms, featuring structural phase transitions. The inherent dissipation of the optical cavity brings in dissipative couplings and drives non-Hermitian dynamics, which is connected to the concept of dissipative time crystal and, in the case of oscillating structural phases, a spontaneous charge (atom) pump. However, the cavity-mediated interaction is naturally an all-to-all interaction, which is an advantage for applications like spin-squeezing generation but a limitation for quantum simulation with finite-range interactions. We are developing a quantum simulation machine with tweezer array of Ytterbium atoms coupled in an optical cavity mode. The site-resolved transverse pump beams enable tailored finite range atom-atom interactions and any-to-any connected qubit networks. Such a system is promising for realizing multiple-qubit entanglement and exploring the crossover from few-to many-body cavity QED systems. |
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F01.00078: Anomalous Stern-Gerlach Measurement of a Two-Component Bose-Einstein Condensate Joseph McGowan, Nick Mantella, Harshil Neeraj, David C Spierings, Aephraim M Steinberg The result of a strong, i.e. accurate, measurement of a quantum system is constrained to lie within the eigenvalue range of the operator being measured. On the other hand, uncertain measurements of a quantum system can, on average, yield results which lie outside this range when the measurement is conditioned on the system being found in a sufficiently unlikely final state. This effect, now known as weak value amplification, has been observed in many systems using photons, including analogues of the original experiment proposed by Aharonov, Albert, and Vaidman where a spin-1/2 system can have a measured spin component of 100. Here, we present progress toward the first realization of such an experiment using massive particles. A condensate of 87Rb in a superposition of two states with different magnetic moments experiences a weak magnetic field gradient. When the spin of the atoms is found to be almost orthogonal to the initial state, the position shift in the resulting cloud is measured. Interference between the weakly shifted and unshifted states results in the overall shift of the post-selected cloud being much larger than possible in a similar strong measurement. |
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F01.00079: Non-Gaussian quantum correlations in many-body bound states of Bose polarons Nader Mostaan, Nathan Goldman, Fabian Grusdt A mobile impurity resonantly coupled to a Bose-Einstein Ccondensate (BEC) forms a quasiparticle termed Bose polaron. Understanding the physical properties of Bose polarons can provide crucial insights into the formation of few-to-many body quantum correlations in Bose-condensed systems. In cold atom realizations of Bose polarons, the impurity-boson interaction strength is tunable via Feshbach resonances, allowing access to interaction regimes beyond the capacity of conventional solid-state platforms. In the strong-coupling regime, the impurity can induce an unstable Bogoliubov mode causing an indefinite cascaded decay of the BEC. We show that the interplay of impurity-induced instability and stabilization by repulsive inter-boson interactions results in a discrete set of states at intermediate energies between attractive and repulsive polaron branches. These states demonstrate strong non Gaussian correlations, requiring non-perturbative beyond-mean field treatments for their characterization. Furthermore, they exhibit vanishing quasiparticle residue and thus are inaccessible by conventional impurity spectroscopy techniques. Nevertheless, we show that they have observable signatures in molecular spectroscopy- based detection techniques. |
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F01.00080: Quantum Gas Microscopy of an XY model in Shaken Triangular Lattices Hideki Ozawa, Ryuta Yamamoto, Takeshi Fukuhara Frustrated spin systems are one of the most intriguing problems of magnetism and condensed matter physics. Even in the case of the simplest geometrical spin frustration that occurs in the triangular structure with antiferromagnetic interactions, competition between the interactions and the lattice geometry can bring about rich spin configurations. There has recently been steady progress in simulating quantum magnetism using a quantum gas microscope (QGM). In our group, we have developed an experimental setup of an 87Rb Bose gas in an optical triangular lattice with QGM, which can reveal real-space properties in the frustrated spin system. To introduce the antiferromagnetic interactions, we use a lattice shaking technique, which enables independent control of the time-averaged effective tunneling by sinusoidally modulating the position of the entire lattice. Mapping the BEC phase onto spins allows the simulation of the XY model. We identify the interference patterns of each phase in the model by the time-of-flight method. A geometrical frustration induced by negative tunneling leads to two-fold ground states corresponding to two chiral modes. Due to spontaneous symmetry breaking, one of the chiral modes randomly appears sequence by sequence. Furthermore, simultaneous occupation of the two chiral modes is occasionally observed, which we attribute to spin domains and/or fragmented states. In this poster, we will report on the investigation of these possibilities by QGM. |
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F01.00081: Superradiance in a many-body system of tilted dipoles of erbium atoms Mithilesh K Parit, Mingchen Huang, Bojeong Seo, Ziting Chen, Yifei He, Haoting Zhen, Gyu-Boong Jo Superradiance is the coherent spontaneous emission from a many-body system, owing to its origin in the simultaneous cooperative interaction among its constituents, initially predicted by R. H. Dicke in 1954. It has been a subject of intense study in various systems, especially in atomic systems. In this poster, we will present our recent observation on superradiant light scattering in a dipolar Bose-Einstein condensate (BEC) of Er atoms [1]. We systematically investigate how s-wave and dipolar interactions affect superradiant light scattering. Our finding opens a new way of characterizing many-body quantum states with light scattering. As an example, we examine the collective light scatter across the phase transition from a dipolar BEC to a quantum droplet. |
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F01.00082: Optical-plug-assisted spin vortex in a 87Rb dipolar spinor Bose-Einstein condensate Hui Tang Generating a spin vortex in a 87Rb dipolar spinor Bose-Einstein condensate in a controllable way is still experimentally challenging. We propose an experimentally easy and tunable way to produce spin vortex by varying the potential barrier height and the width of an additionally applied optical plug. A topological phase transition occurs from the trivial single mode approximation phase to the optical-plug-assisted-vortex one, as the barrier height increases and the width lies in an appropriate range. The optical plug causes radial density variation thus the spin vortex is favored by signifificantly lowering the intrinsic magnetic dipolar energy. A type of coreless spin vortex, difffferent from the conventional polar core vortex, is predicted by our numerical results. Our proposal removes a major obstacle to investigate the topological phase transition in a 87Rb dipolar spinor BEC. |
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F01.00083: Towards robust neutral-atom BEC production with the help of machine learning Arina Tashchilina, Nicholas Milson, Tian Ooi, Anna Prus-Czarnecka, Lindsay J LeBlanc Producing neutral-atom Bose-Einstein condensation, despite being a routine procedure, remains susceptible to experimental imperfections. In order to reach the condensation of widely used atomic species such as rubidium, researchers require ultrahigh vacuum, high current sources, and stable, precision lasers. The BECs are sensitive to residual magnetic fields, low-power scattered resonant light, and even to the humidity of a room. Despite best efforts, we observed a significant atom number drift in our system with different timescales. Due to the process being divided into many temporal steps and multiple independent parameters associated with different cooling mechanisms, we were unable to identify some causes of the drift. |
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F01.00084: Feedback cooled Bose-Einstein condensation: near and far from equilibrium Evan P Yamaguchi, Hilary M Hurst, Ian B Spielman Continuously measured interacting quantum systems almost invariably heat, causing loss of quantum coherence. We study Bose-Einstein condensates (BECs) subject to repeated weak measurement of the atomic density and describe several protocols for generating a feedback signal designed to remove excitations created by measurement backaction. We use a stochastic Gross-Pitaevskii equation to model the system dynamics and develop feedback protocols that effectively cool both 1D and 2D BECs. Furthermore, we use this protocol to quench-cool 1D BECs from non-condensed highly excited states and find that they rapidly condense into a far from equilibrium state. We observe that these quench-cooled condensed states can have non-zero integer winding numbers described by quantized supercurrents. |
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F01.00085: Exploring low-temperature phases of spin-imbalanced 2D Fermi gases in box potentials Hauke Biss, René Henke, Cesar R Cabrera, Henning Moritz In recent years, our group has created homogeneous ultracold Fermi gases in two-dimensional and three-dimensional box potentials. Using Bragg spectroscopy we have determined the dynamic structure factor of spin-balanced superfluids in the BEC-BCS crossover and extracted both the superfluid gap and the critical velocity from it [1-2]. By directly comparing 2D and 3D superfluids we could directly observe the influence of dimensionality on the stability of these strongly interacting fermionic superfluids [3]. |
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F01.00086: Probing two-body interactions in a deep three-dimensional optical lattice Robyn T Learn, Vijin Venu, Peihang Xu, Mikhail Mamaev, Frank Corapi, Benjamin Driesen, Thomas Bilitewski, Jose P D'Incao, Coraline J Fujiwara, Ana Maria Rey, Joseph H Thywissen Experimental control and readout of two-body interacting systems can enhance understanding of many-body states. Here, we use a deep 3D optical lattice to form isolated pairs of fermionic 40K atoms. We report on two experiments that probe s- and p-wave interacting pair states in this two-body system. |
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F01.00087: Spin- and charge-doped attractive Fermi-Hubbard model under a quantum gas microscope Botond Oreg, Thomas R Hartke, Carter Turnbaugh, Ningyuan Jia, Martin W Zwierlein The attractive Fermi-Hubbard model away from half-filling and spin balanced is predicted to host a variety of exotic phases, such as FFLO superfluidity. By harnessing the power of a quantum gas microscope, we are able to perform spin and charged resolved measurements with single-site resolution. With these measurements, we explore the microscopic properties of fermion pairing at various densities, magnetizations, and interaction strengths. We first confirm the robustness of local and non-local fermion pairing by observing the suppressed spin-fluctuation around minority atoms. Furthermore, with the ability to extract all spin and density correlations, we observe the emergence of many-body ordering of fermion pairs at high density and a degenerate fermi surface with increasing magnetization. Finally, we combine these microscopic correlator measurements to classify the behavior of the system as the density and spin imbalance are varied. |
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F01.00088: Quantifying Turbulence in Unitary Fermi Gas Saptarshi R Sarkar, Michael M Forbes, Gabriel Wlazlowski We analyze the largest fermionic cold atom simulations where turbulence is imprinted externally in the form of a vortex lattice along all 3 dimensions. Although numerically the vortex length can be calculated, experimentally measuring it is extremely difficult. We want to have a mesoscopic picture of turbulence, starting withthe axisymmetric model. |
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F01.00089: Transport Properties in the Unitary Fermi Gas Eric Wolf, Huan Q Bui, Zhenjie Yan, Parth B Patel, Biswaroop Mukherjee, Richard J Fletcher, Martin W Zwierlein Understanding transport in strongly correlated fermion systems is among the grand challenges of many-body physics. Atomic Fermi gases near a Feshbach resonance serve as a paradigmatic form of fermionic matter, with strong connections to high-temperature superconductors, nuclear matter, and neutron stars. We here study the transport of density and heat in a resonant, two-component Fermi mixture of 6Li in a uniform box potential by resonantly exciting low-frequency modes. We spatially resolve both the local density and temperature of the balanced spin mixture, allowing us to measure both the density-density and entropy-density response and to observe the onset of "second sound" below the superfluid transition. By imbalancing the spin mixture, we observe a strong increase in damping of first sound as the gas turns normal beyond the Clogston-Chandrasekhar limit of superfluidity. Our measurements elucidate the interplay of spin, density, and heat transport in strongly interacting Fermi systems, and may in the future serve as a marker for phase transitions into exotic states of fermionic matter. |
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F01.00090: Thermodynamics of weakly interacting single-component Fermi gases Yangqian Yan, Xin-Yuan Gao, D. Blume, Tobias Dornheim Weakly interacting single-component Fermi gases could be realized in ultracold atomic (e.g. K and Li) and molecular (e.g., KRb) gases and trapped ions. This work studies thermodynamic quantities such as the contact and moment of inertia of the Fermi gas. I. The contacts, which could be defined as thermodynamic extensive variables that are conjugate to microscopic two-body interacting parameters, dictate the chemical reaction and thus the loss rate of reactive molecules. This work resolves the loss rate of reactive molecules and the contact of a single-component Fermi gas in the normal state as a function of temperature. II. The moment of inertia could be obtained by measuring the increase of angular momentum after a small rotation. The moment of inertia as a function of temperature is obtained for a few trapped ions. In both cases, as the system reaches quantum degeneracy, drastically different behaviour occurs: I. loss rate deviates away from linear temperature dependence; II. moment of inertia becomes larger than the classical moment of inertia. |
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F01.00091: Spin-Nematic Squeezing in a Spin-1 BEC Using Novel Quench Techniques Maryrose Barrios, Julia T Cohen, Lin Xin, Michael S Chapman Spin-nematic squeezing in a spin-1 condensate has been created using several methods exploiting the second-order continuous quantum phase transition using deep magnetic quenches, parametric/Floquet excitation, and adiabatic and short-cut methods to generate squeezed ground states. In this work, we explore new methods that exploit the exceptional controllability of the system Hamiltonian. |
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F01.00092: 3-domain spin dynamics in an ultracold Rb-87 gas Olha Farion, Mehdi Pourzand, Jeffrey McGuirk We investigate the motion of spin domain walls in a nondegenerate trapped pseudo-spin-1/2 Bose gas. Using customizable optical potentials, we initialize structures of three domains separated by narrow domain walls and study the short-time wall motion in a spin-independent potential. Our experiments reveal the strong influence of the local imbalance of spin-up and spin-down atoms in the domains on the domain-wall trajectories. This "spin impurity," particularly manifested by the presence of transverse spin in the middle domain, leads to increased spin-exchange collisions and induces spin currents, thereby driving wall motion. We also study the effects of trap symmetry on the wall trajectories by creating both symmetric and asymmetric domains. |
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F01.00093: Characterization of Spin-Driven Stationary Turbulence in Spinor Bose-Einstein Condensates Jongheum Jung, Junghoon Lee, Jongmin Kim, Deokhwa Hong, Yong-il Shin This poster presents our observation of stationary turbulence in antiferromagnetic spin-1 Bose-Einstein condensates under radio-frequency magnetic field driving. The magnetic driving injects energy into the system by spin rotation and the energy is dissipated via dynamic instability, resulting in the development of an irregular spin texture in the condensate. With continuous driving, the spinor condensate evolves into a nonequilibrium steady state with characteristic spin turbulence. To enrich our understanding, we explored various system parameters determining features of the turbulence. One of our findings is that as the driving strength approaches the system's intrinsic energy scale, the spin composition of the stationary turbulence becomes isotropic. We will also discuss the roles of driving frequency, noise and quadratic Zeeman energy on the emergence of spin turbulence. |
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F01.00094: Modifying the Momentum Distribution of One-Dimensional Spin-Orbit-Coupled Bose Gases Shih-Wen Feng, Chuan-Hsun Li, Felicia Martinez, Qi Zhou, Yong P Chen Momentum distribution manifests some properties of a quantum system. For instance, temperature, interparticle interactions and dimensionality can affect the shape of the momentum distribution. We experimentally investigate one-dimensional (1D) spin-orbit-coupled Bose gases, which energy-momentum dispersion and the corresponding momentum distribution are engineered by changing the parameters of the spin-orbit coupling (SOC). The Luttinger liquid theory is usually used to describe the low-energy properties of 1D quantum systems. To go beyond the Luttinger liquid theory, the nonlinear dispersion is an essential feature. SOC provides an alternative method to reach such novel phenomena in 1D quantum systems. We find that the Raman coupling strength around the critical value notably modifies the 1D momentum distribution to an exponential decay form, which goes beyond the power-law-decay prediction of the Luttinger liquid theory. |
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F01.00095: Topological Nodal Rings in a Bose-Einstein Condensate Chuan-Hsun Li, Shih-Wen Feng, Felicia Martinez, Yangqian Yan, Chenwei Lv, Qi Zhou, Yong P Chen Nodal structures are topological defects that play important roles in topological matter. While zero-dimensional nodal points such as Dirac points have been studied extensively, higher-dimensional nodal lines or surfaces further enrich topological physics but require more research. Here we experimentally probe a topological nodal ring in a Bose-Einstein condensate, whose four hyperfine spin states are cyclically coupled by microwaves and radio-frequency waves. The ring emerges in a parameter space constituted by the light fields’ coupling strengths, phases, and detunings. When tuning the parameters, this ring can expand or shrink to a point but can never be gapped out. Such stability corresponds to a unique second topological invariant and can be understood from a high-dimensional perspective, a nodal hyperboloid or cone in the parameter space. Moreover, the projection of the hyperboloid or cone into low dimensions also sheds light on the evolution of two nodal lines when tuning the parameters. Our study may provide insights into exploring high-dimensional topological defects and the evolution of their projections in synthetic quantum matter. |
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F01.00096: Experimental realization of Qi-Wu-Zhang model with spin-orbit-coupled ultracold fermions Ming-Cheng Liang, Yu-Dong Wei, Long Zhang, Xu-Jie Wang, Han Zhang, Wen-Wei Wang, Wei Qi, Xiong-Jun Liu, Xibo Zhang Ultracold atoms can be used for simulating various physical systems. As one of the fundamental models for the quantum anomalous Hall (QAH) effect, the Qi-Wu-Zhang model has broad impact on condensed matter research and becomes a building block for many other models. Alkaline-earth atoms, with the featured two-electron outer shell structure, possess additional advantages for realizing spin-orbit-coupled systems and the Qi-Wu-Zhang model. Based on the optical Raman lattice technique, we report experimental realization of the Qi-Wu-Zhang model for the QAH phase in ultracold Sr-87 fermions with two-dimensional (2D) spin-orbit (SO) coupling. We develop an experimental protocol of pump-probe quench measurement to probe, with minimal heating, the resonant spin flipping on particular quasi-momentum subspaces called band-inversion surfaces. With this protocol we demonstrate Dirac-type 2D SO coupling in a fermionic system and detect nontrivial band topology by observing the change of band-inversion surfaces as the two-photon detuning is tuned. Furthermore, we slowly load atoms into optical Raman lattices and observe the non-trivial band topology by measuring the spin textures. |
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F01.00097: Observation of a Topological Phase Transition with Deep Neural Networks in spin-orbit-coupled fermions Yujun LIU, Yunchu Li, Ka Kwan Pak, Peng Ren, Entong ZHAO, Chengdong HE, Gyu-Boong Jo Machine Learning (ML) techniques have emerged as a powerful tool in quantum matter research. In this poster, we highlight how ML algorithms enable us to analyze experimental data with unprecedented high sensitivities and identify topological phases even in the presence of unavoidable noises. To this end, we apply the trained network to low signal-to-noise-ratio (SNR) experimental data obtained in a symmetry-protected topological system of spin-orbit-coupled fermions [1]. The obtained phase diagram by ML is consistent with the results obtained by using the conventional method on higher SNR data. Our work highlights the potential of machine learning techniques to be used in various quantum systems. |
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F01.00098: Toward arbitrary control of the quantum state in non-Hermitian spin-orbit coupled Fermi gases Ka Kwan PAK, Entong ZHAO, Chengdong HE, Yujun Liu, Peng Ren, Gyu-Boong Jo Non-Hermitian spin-orbit coupled system is becoming attractive as its special features, such as non-Hermitian skin effect and chiral response when encircling around exceptional point (EP). Such a situation can be realized in 173Yb fermions by means of optical coupling between two internal states with atoms loss induced by a near-resonant light [1]. Here, we lay out our strategy for controlling quantum states on-demand near the EP. To minimize incoherent relaxation, we utilize a clock transition 578 nm, 1S0 → 3P0 in 173Yb as the dissipation laser, which benefits from a longer lifetime in 3P0 and less spontaneous emission [2], with another blast laser to remove atoms in excited 3P0 state. We will discuss how to prepare an arbitrary quantum state when encircling around the EP in the parameter space. A chiral behavior near the EP will be also discussed. |
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F01.00099: Quench dynamics of Bose-Einstein condensates in the presence of synthetic spin-orbit coupling Federico Serrano, Qingze Guan The discovery of synthetic 1D spin-orbit coupling (SOC) (equal mixture of Rashba and Dresselhaus strengths) using a Raman laser scheme has sparked numerous studies on mimicking condensed matter physics in cold atoms, such as non-Abelian gauge fields, topological phase transitions, spin transportations, and Majorana devices. The high tunability of ultracold quantum gas allows for exploration of various SOC physics in a wider parameter regime. These interparticle interactions in cold atoms create a complex phase diagram for SOC systems, including the plane wave phase, single minimum phase, and supersolid phase. This study examines the dynamics of the 1D SOC system close to the various critical points as SOC parameters are tuned, resulting in the formation of defects (Kibble-Zurek mechanism) which can be analyzed through numerical simulation and the Bogoliubov theory. |
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F01.00100: Rotating Bose-Einstein condensate in a box potential Ruixiao Yao, Sungjae Chi, Airlia Shaffer, Richard J Fletcher, Martin W Zwierlein We use a rapidly-rotating Bose-Einstein condensate confined by a cylindrical optical potential to realize a uniform quantum fluid subject to a synthetic magnetic field. We use this setup to explore the propagation of chiral edge modes at the boundary, and the physics of homogenous vortex liquids. For edge states, we determine the their speed as a function of energy, which serves as direct probe for edge channel dispersion. For vortex liquids we demonstrate that the bulk vortex density equals to Feynman's number, and the vortex-vortex correlation function directly reflects their pair-wise interaction. Intriguingly, even in the limit of non-interacting bosons in the lowest Landau level, the vortices, as zeroes of random polynomials, are still predicted to repel. |
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F01.00101: COLD ATOMS, IONS, MOLECULES, PLASMAS
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F01.00102: Dressed Efimov trimers in periodically driven magnetic fields George Bougas, Panagiotis Giannakeas, Simeon I Mistakidis, Jose P D'Incao, Peter Schmelcher, Hossein R Sadeghpour The interactions between three identical atoms are driven by means of oscillating magnetic fields near a Feshbach resonance, and the properties of dressed Efimov states are investigated. A three-body approach is constructed by combining the adiabatic hyperspherical representation approach along with a quasi-static Floquet representation. This theoretical framework permits the description of the three-body dynamics to be expressed in terms of hyperspherical potential curves spanning over different Floquet manifolds. It is found that the potential curve landscape of three atoms intrinsically differs from the undriven case giving rise to a class of dressed trimer states experiencing a short range three-body repulsion. The latter depends on the driving frequency as well as the strength of the modulating magnetic fields paving the way for lifetime tunability of dressed Efimov states. |
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F01.00103: Understanding Multichannel nature of Efimov physics with ultracold 7Li atoms Jose P D'Incao, Yaakov Yudkin, Paul S Julienne, Lev Khaykovich We present our current understanding of various aspects of Efimov physics originating from the complex multichannel hyperfine structure which further help us to understand puzzling 7Li experimental observations. Our results indicates that spin-exchange for 7Li atoms play an important role in the determination of Efimov resonances along with the narrow character of its Feshbach resonances. We show that the structure of three-body potentials is strongly dependent on the resonance width giving further insights to other atomic species. |
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F01.00104: Different Classes of Triatomic Molecules in Ultracold environment Ahmed A Elkamshishy, Chris H Greene The study of ultracold collisions of neutral atoms and molecules provides a valuable environment to observe quantum effects at very low temperatures, which has garnered much attention due to recent experimental advancements in cooling and trapping these species. In this survey, we examine two different classes of ultracold trimers. The first class is a long-range triatomic molecule formed by the collision of a ground state atom (S) and a ground state dimer, with the absorption of a photon at a frequency red-detuned from the atomic resonance line [endif]-->. The laser frequency can be detuned to different vibrational trimer states [1,2]. The second class of interest is the ultra-long-range molecules (ULRMs), created when a highly excited Rydberg electron collides with two ground state atoms. This results in various triatomic molecular states with different geometries, including separable potential energy in the case of an S electronic state. However, this separability breaks down in the case of a [endif]--> electronic state due to the degeneracy of the [endif]--> manifold. We explore these different types of molecular states in Rb (n=15) hydrogenic manifold. |
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F01.00105: Ion-atom-atom recombination into shallow molecular ions Panagiotis Giannakeas, Jesus Perez Rios This work presents a full quantum mechanical study on ion-atom-atom three-body recombination into shallow molecular ions. In particular, we consider a heavy positive ion ($A^+$) and two light neutral atoms ($B$) and our theoretical framework addresses the finite range of atom-ion and atom-atom interactions. For fixed and positive atom-ion scattering length ($a_{A^+B}$), the scaling behavior of the three-body recombination coefficient versus the atom-atom scattering length ($a_{BB}$) is obtained. We identify two distinct regimes where the three-body recombination coefficient possesses different scaling behavior with respect to $a_{BB}$. More specifically, these two regimes are indicated by the magnitude of the atom-ion scattering length relative to the corresponding atom-ion interaction length scale ($R_{A^+B}$). |
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F01.00106: Hyperfine and Zeeman interactions in ultracold collisions of molecular hydrogen with Li atoms Hubert Jozwiak, Timur V Tscherbul, Piotr Wcislo Cold collisions involving molecular hydrogen (H2) have been the subject of significant interest across various contexts, from astrochemistry of the interstellar medium to controlled chemistry at extremely low temperatures. However, previous theoretical studies of such collisions neglected the effects of hyperfine interactions and Zeeman shifts, which could be substantial at ultracold conditions (the hyperfine structure of ortho-H2 in the first rotational state is on the order of 20 μK). |
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F01.00107: Non-Adiabatic Quantum Dynamics of Ultracold Collisions of Rb with KRb Brian K Kendrick, Hui Li, Jacek Klos, Svetlana Kotochigova Inspired by a recent ultracold experiment[1] on non-reactive Rb + KRb collisions that reports universal two-body trap losses and long-lived KRb2 collision complexes, we perform the first-principle quantum dynamics calculations for ultracold collisions of Rb with KRb in its ground rovibrational state. Accurate ab-initio electronic potential energy surfaces are used, which include both the ground and first excited electronic states. Both electronic states are energetically accessible within the interaction region and must be included in the quantum dynamics calculations even at ultracold collision energies. The two electronic states become degenerate and exhibit a conical intersection that leads to significant non-adiabatic quantum interference effects.[2] In addition, the excited electronic state potential energy surface supports bound states that can lead to long-lived collision complexes (Feshbach resonances), which may be responsible for the unexplained long lifetimes observed by [1]. Elastic cross sections and time-delays are reported as a function of collision energy from 1 nK to 1 K using a high resolution energy grid. Intriguing non-adiabatic quantum interference and resonance effects are reported that lead to significant enhancement and suppression of the cross sections providing unique insight into the mechanisms of ultracold collisions and complex formation. |
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F01.00108: Control of an Ultracold Photochemical Reaction via Quantum Interference Felicia Martinez, Chuan-Hsun Li, Shih-Wen Feng, David Blasing, Qi Zhou, Yong P. Chen Ultracold atomic systems are a rich platform for studying numerous quantum phenomena due to their amenability to being precisely controlled and widely tunable. One such phenomenon we would like to study is control over the rate of photoassociation (PA) of two Rb atoms into an Rb2 molecule by carefully preparing the reactants in superposition states. We have studied PA in a Raman-dressed 87Rb Bose-Einstein condensate (BEC) and a radio frequency (RF)-dressed BEC. In the Raman-dressed case we have experimentally observed changes in the PA rate consistent with our theory of destructive interference between the two allowed PA pathways for our selected scattering state. In addition, we propose an RF-dressed scheme for full control of the interference between PA pathways by varying the relative phase between the RF couplings. We will also show the experimental progress towards realizing such a scheme. |
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F01.00109: Cavity enhanced formation of ultracold molecules: polaritonic ultracold chemistry Vasil Rokaj, Simeon I Mistakidis, Hossein R Sadeghpour The experimental demonstration of strong coupling between cavity photons and vibrational states in organic molecules heralds the possibility of controlling chemical reactions with cavity vacuum fields. Photoassociation is an established technique for bound molecules in collision between atomic pairs. In this work we consider a rubidium dimer (Rb2) strongly coupled to a cavity. We show that at the avoided crossings (Rabi splitting) between the vibrational excitation and vaccum photon absorption, polaritonic states between the molecule and photons form, which can significantly enhance the Franck-Condon factors of Rb2 from the excited potential energy surface to the ground-state manifold. This work paves the way for the control of photoassociation of ultracold molecules with strong light-matter interaction. |
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F01.00110: Förster dynamics within the Stark manifold Samantha A Grubb, Alan T Okinaka, Catherine D Opsahl, Sarah E Spielman, Thomas J Carroll, Michael W Noel, Nicolaus A Chlanda, Hannah S Conley The resonant energy exchange among ultracold Rydberg atoms has been used as an analog to shed light on the dynamics in quantum systems. However, most studies of the dipole-dipole interaction have explored systems with few initial and final states. We have measured the time dependence of the dipole-dipole-mediated redistribution of population among manifold states for atoms initially excited near the center of the Stark manifold, where the states form a nearly harmonic ladder. Energy exchange occurs rapidly but is limited due to the increasing anharmonicity of more distant manifold energy levels. We compare our experimental results to a computational model which includes about 40 manifold levels. |
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F01.00111: Characterizing the Decoherence of Three-Atom Entangled States Near Förster Resonance Emily Hirsch, Lucy Shamel, Tomohisa Yoda, Dilara Sen, Gabriella Pesticci, Dominick Frost, Aaron Reinhard We recently demonstrated coherent excitation of entangled states of three Rydberg atoms near a Förster resonance in 85Rb [1]. The coherence was proved using an optical rotary echo technique. In this poster, we expand on those measurements to determine the decoherence time. We present progress towards fully characterizing decoherence using Ramsey interferometry. The triply-excited entangled states are created in a disordered optical dipole trap. Therefore, our scheme shows promise for the application of three-atom entanglement to quantum protocols in simple atomic systems. |
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F01.00112: Floquet driving on a pair of Rydberg atoms Michael Dao Kang Lee, Luheng Zhao, Mohammad Mujahid Aliyu, Krishna Chaitanya Yellapragada, Huanqian Loh In recent years, the Rydberg atom array platform has attracted much attention due to its applications in quantum simulation and information processing. To enhance the versatility of this platform, we explore the use of Floquet driving as an independent degree of control during the Rydberg excitation process. We report the observation of several types of unusual dynamics, such as facilitation of closely spaced Rydberg atoms driven on resonance, Rydberg blockade of two atoms separated beyond the static blockade radius, and population trapping. The experimental observations are backed by theoretical calculations that account for experimental imperfections including a finite position uncertainty of the atoms, Doppler shift, and Rydberg state lifetime. Overall, Floquet driving provides an additional means to control Rydberg-atom dynamics, paving the way for novel implementations of quantum simulation and gate protocols. |
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F01.00113: PRECISION MEASUREMENT & GPMFC STUDENT POSTER PRIZE
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F01.00114: Work on Precision Helium Spectroscopy: Some Experimental Details with Regard to Laser Alignment and B Field Measurement and Modeling. Jeffrey Pound, Garnet Cameron, Joe Tidwell, David C Shiner In laser spectroscopy of an atomic beam, laser beam retroreflection to minimize first order Doppler shifts can introduce unwanted power dependence in the atomic resonant frequencies. In our experiment, we work to reduce these effects (related to laser cooling) while keeping the advantages of retroreflection. We do this through coupled fiber to free space beams, fiber optic switches, automated pico-motor control and good passive and active stability. Additionally in our experiment, magnetic fields required for the source and optical pumping regions can interfere with each other and with other regions, exacerbated by compactness goals. Physical intuition often leads to adequate designs of magnetic sources and materials, but the use of standard finite element analysis software tools is useful to verify and quantify expectations in combination with measurements. These and other ongoing experimental details will be discussed. |
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F01.00115: Measurement of the hyperfine coupling constants and absolute energies of the 8p 2P1/2 and 8p 2P3/2 levels in atomic cesium Jonah Quirk, Liam Sherman, Amy Damitz, Carol E Tanner, Daniel Elliott We report measurements of the hyperfine coupling constant for the 8p 2P1/2 level of atomic cesium, 133Cs, with a relative uncertainty of ∼0.019%. Our result is A = 42.933 (8) MHz, ten times more precise than the previous best measurement, and in good agreement with recent theoretical results. We also examine the hyperfine structure of the 8p 2P3/2 level, and derive new values for the energies of the 8p 2P1/2 and 8p 2P3/2 levels of cesium. |
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F01.00116: Microwave spectroscopy of the positronium fine structure Samuel H Reeder, Stephen D Hogan, David B Cassidy Using a Surko-type buffer gas positron trap [1] and single-shot annihilation lifetime techniques [2] we have performed new measurements of the positronium (Ps) fine structure using microwave spectroscopy [3]. Such experiments may be used to test QED but are presently much less precise than theory [4]. Measurements made in both free-space and in waveguides were found to be susceptible to line shape distortions arising from reflected microwave radiation [5], which in turn resulted in large apparent frequency shifts. We report here new waveguide measurements designed to mitigate these effects and which allow for increased precision and accuracy. We also describe a new technique in which microwave spectroscopy of dressed Rydberg He atoms is used to characterize the electric field in a waveguide [6]. |
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F01.00117: Progress Towards Measuring the Nuclear Spin Coherence of Molecules in Solid Parahydrogen Alex Rollings, Jonathan D Weinstein Prior experiments have demonstrated long nuclear spin coherence times for matrix-isolated molecules in solid parahydrogen. The nuclear spin coherence was limited by the presence of orthohydrogen impurities [Journal of Low Temperature Physics 45, 167 (1981)]. We have demonstrated the ability to grow solid hydrogen samples with orthohydrogen fractions that are orders-of-magnitude lower than this prior work [Review of Scientific Instruments 92, 073202 (2021)]. The objective of our current research is to use NMR techniques to measure the nuclear spin coherence times of molecules trapped in these high-purity parahydrogen matrices. If, as expected, long coherence times are achieved, this would be of interest for fundamental physics measurements. We are in the process of completing construction of an apparatus capable of performing such measurements for a variety of molecules; progress towards this goal will be presented. |
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F01.00118: Two Photon Direct Frequency Comb Spectroscopy of the 1S-3S Transition in Hydrogen Derya O Taray, Alexey Grinin, Vitaly Wirthl, Omer Amit, Dylan C Yost, Randolf Pohl, Thomas Udem, Theodor Hansch The energy levels of hydrogen-like atoms can be both calculated and measured very precisely. Precision spectroscopy of two transitions at the current level of accuracy allows the determination of the Rydberg constant and the proton charge radius. Comparison with additional transitions serves as a consistency check for the theory of quantum electrodynamics. The recent discrepancy in these consistency checks is known as the proton radius puzzle. |
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F01.00119: Search Efforts for the 229Th Isomeric Transition James E Terhune, Ricky Elwell, Justin Jeet, Christian Schneider, Eugene Tkalya, Hoang Bao Tran Tan, Andrei P Derevianko, Eric R Hudson In the 229Th nucleus, there exists a relatively low-energy isomeric state that is 8.338(24) eV above the nuclear ground state [1]. It has been noted that the characteristics of this transition make it a promising platform for an ultra-high precision nuclear clock [2]. Due to its low energy, this state can be directly excited with a laser that is tuned into the vacuum-ultraviolet (VUV) spectrum. Our work has centered around exciting this transition using a tunable dye laser system in order to more accurately resolve the uncertainty in the transition energy to several GHz. We will report on our recent progress towards addressing the 229Th nucleus and potential couplings between the 229Th nucleus and its chemical environment in a LiSAF crystal [3]. |
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F01.00120: Optical Clocks Based on Highly Charged Ions for Tests of Fundamental Physics and Improved Frequency Standards Alessandro L Banducci, David Fairbank, Robert Gunkelman, Jacob B VanArsdale, Samuel M Brewer, Haoran Ding, Aung Naing, Hashini Nawarathnage Optical clocks based on highly charged ions (HCIs) offer a number of promising avenues for the study of physics beyond the standard model. Among these are searches for time variation of the fine structure constant, α?/α, and tests of quantum electrodynamics (QED). Due to level crossings occurring in high charge states, narrow linewidth, optically accessible transitions with a high sensitivity to α?/α are predicted in both Nd10+ and Pr10+. We demonstrate a compact electron beam ion trap (EBIT) capable of producing these ions and our plans to transfer them into a cryogenic Paul trap where they will be co-trapped with Be+ for sympathic cooling and quantum-logic spectroscopy (QLS). In addition, we present an update on the development of a Ba4+ source and quantum-logic clock as an improved optical frequency standard. |
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F01.00121: Measuring the n=2 triplet P fine structure of atomic helium using frequency-offset separated oscillatory fields Farshad Heydarizadmotlagh, Taylor D Skinner, Kosuke Kato, Matthew C George, Eric A Hessels The n=2 triplet P fine structure of atomic helium is being measured using microwave transitions. |
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F01.00122: Deflection of barium-monofluoride molecules Daniel Heinrich, Alain Marsman, Zachary Corriveau, Hin-Man Yau, Neil T McCall, Jorge Perez Garcia, Gregory K Koyanagi, Matthew C George, Cody H Storry, Ricardo L Lambo, Marko Horbatsch, Eric A Hessels The EDMcubed scheme [1] for measuring the electron electric dipole moment using BaF embedded in an Ar solid requires a BaF deflection to separate BaF from other products produced in a buffer-gas laser-ablation source. Both experimental and theoretical progress will be presented on implementing this deflection. Density-matrix simulations of an optical scheme for producing a large optical force on barium-monofluoride (BaF) molecules [2] will be presented. The scheme uses short laser pulses to induce excitation to the A Pi 1/2 state, with pulses from counter-propagating laser beams causing stimulated emission back to the ground electronic state. A magnetic field is used to remove degeneracies to avoid dark states. The calculated force is an order of magnitude larger than the maximum force possible with CW laser schemes. Because the molecules spend little time in the excited state, spontaneous decay is minimized, reducing or eliminating the need for re-pump lasers from other states (e.g., other ground vibrational states). An alternate scheme using bichromatic forces will also be discussed. Experimental progress on using electrostatic deflection will also be presented. |
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F01.00123: Progress towards a measurement of the nuclear anapole moment in cesium Amy Damitz, Jonah Quirk, Daniel Elliott, Carol E Tanner We report progress towards a measurement of the anapole moment in cesium, 133Cs. We use an atomic beam interacting with a rf field and Raman field that are coherent with each other. The rf field drives a weak electric dipole interaction between the hyperfine components of the ground state of cesium (6s2S1/2 F=3 → 6s2S1/2 F=4), which is weakly allowed due to the influence of the nuclear anapole moment. The Raman field initializes the atoms in a 50-50 mixed state between the two hyperfine ground states. We use detailed numerical calculations of the rf field modes in a cavity and numerical integration of the equations of motion of the state amplitudes to calculate the expected magnitude of the Bloch vector. The relative magnitude of this modulation is expected to be ≈ 5 x 10-6, which we show to be measurable in the laboratory. We modeled the rf field in the rf cavity we designed to enhance the PNC interaction and reduce the magnetic dipole interaction. Finally, we have observed coherent interaction between the Raman and magnetic rf interactions. |
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F01.00124: Optical Pumping for Beta-decay Neutrino Helicity Tests John A Behr, Hannah Gallop, Melisa Ozen, Felix Klose We seek to improve our measurements of beta and neutrino asymmetry of direction with respect to the nuclear spin, similar to the first measurements that demonstrated that parity was broken by the weak interaction. Our decay measurements depend on achieving high atomic (hence nuclear) spin polarization of laser-cooled potassium atoms. This poster summarizes long-term improvements of circularly polarized light quality for optical pumping, magnetic field switching from MOT configuration to constant field, and measurements of the resulting spin polarization of stable laser-cooled 41K atoms. |
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F01.00125: ACME III Electron Electric Dipole Moment Search Zhen Han The electric dipole moment of electron (eEDM, de) with a value around the current limit is theorized to originate from time-reversal- (T-) violating physics beyond Standard Model. The ACME experiment uses a cold beam of ThO molecules to probe for the eEDM. The third generation experiment (ACME III) aims to improve on the most recently published (ACME II) result of |de|<1.1×10-29 e·cm. 1 2 |
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F01.00126: Barium-monofluoride within argon and neon solids: Calculations to support the EDMcubed scheme for measuring the electron electric dipole moment Ricardo L Lambo, Gregory K Koyanagi, Marko Horbatsch, René Fournier, Eric A Hessels The EDMcubed collaboration is working towards a measurement of the electric dipole moment of the electron (eEDM) using barium-monofluoride (BaF) embedded in an argon solid. The large numbers of embedded BaF in this measurement scheme [1] gives the potential for a very precise eEDM measurement. In this work, we present precise relativistic electronic structure calculations (all-electron, with an extrapolation to a complete basis set) of the BaF-Ar [2] and BaF-Ne tri-atomic system, for a wide range of BaF-Ar separations and angles. The resulting potentials can be parameterized and used to model a BaF molecule embedded into an Ar [3] or Ne solid to determine the structure of the local environment around the BaF molecule. |
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F01.00127: EDMcubed (Electric Dipole measurement using Molecules in a Matrix): Towards a measurement of the electron electric dipole moment using BaF molecules embedded in a solid Ar matrix Eric A Hessels, Zachary Corriveau, Daniel Heinrich, Jorge Perez Garcia, Hin-Man Yau, Neil T McCall, Gregory K Koyanagi, Matthew C George, Cody H Storry, Ricardo L Lambo Improved measurements of the electron electric dipole moment (eEDM) will strongly constrain the parameter space of new physics theories. Over the last decade, polar molecules have become established as the most promising systems for eEDM searches, due to the large internal electric fields experienced by an eEDM in these molecules. The sensitivity of eEDM searches is determined by the coherence time available for measuring eEDM-induced electron spin precession, as well as by the total number of molecules available over the course of a measurement. We present our progress in implementing a measurement scheme [1] that will use a large number of barium-monofluoride molecules embedded into a solid argon matrix. The large number of BaF molecules embedded in our Ar solid is expected to lead to excellent statistical precision, and the method offers an array of reversals and controls for cleanly suppressing systematic effects to a level commensurate with the improved statistical precision. Experimental progress in creating and studying BaF doped solids will be presented. |
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F01.00128: Going beyond the new JILA eEDM result with a multiplexed experiment using ThF+ Kia Boon Ng, Trevor Wright, Noah Schlossberger, Sun Yool Park, Anzhou Wang, Luke A Caldwell, Jun Ye, Eric A Cornell The Standard Model of particle physics is one of the most successful models that we use to describe the universe, yet it is known to be incomplete. Substantial efforts on the theoretical front introduce new physics through extensions of the Standard Model, and these new physics models make predictions on the value of the electric dipole moment of the electron (eEDM). Measurements of (or improved limit on) the eEDM places constraints on these new theories. The eEDM experiments at JILA take advantage of the long trapping time of ions to tap the long coherence times of the eEDM-sensitive states in our molecular ions of choice: HfF+ and ThF+. The recently concluded experiment using HfF+ [1,2] is an upgraded version of our 2017 experiment [3], using a bigger trap for more ions, amongst other improvements for better statistics. The upcoming experiment using ThF+ has recently completed spectroscopy of the molecule [4-6], and we are now setting up a prototype experiment to demonstrate the much longer coherence times promised to us by the eEDM-sensitive ground state in ThF+ [4,6]. We repoprt on progress towards observation of long coherence times in ThF+. |
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F01.00129: Next Steps in the Search for Non-Interacting Particles Experimental Hunt (SNIPE Hunt) Katie Hermanson, Brittany Karki, Derek F Jackson Kimball, Ariel Arza, Itay M Bloch, Eduardo Castro Muñoz, Chris Fabian, Michael A Fedderke, Madison Forseth, Peter Graham, Erik B Helgren, Andres Interiano-Alvarado, Saarik Kalia, Will Griffith, Abaz Kryemadhi, Andre Li, Ehsanullah Nikfar, Warner Serrano, Jason E Stalnaker, Ibrahim Sulai, Yicheng Wang The Earth can act as a transducer for ultralight dark-matter detection: hidden-photon or axion-like particle (ALP) dark matter can induce a coherent global magnetic field pattern [1-3]. We discuss the next generation of the Search for Non-Interacting Particles Experimental Hunt (SNIPE Hunt), a search for oscillating magnetic signals due to ultralight bosonic dark matter. We use a network of atomic magnetometers located in relatively quiet magnetic environments, namely in the wilderness far from human-generated magnetic noise. The next generation of the SNIPE Hunt targets higher frequencies (in the 5 Hz to 1 kHz range) and will employ induction-coil magnetometers. In order to clearly interpret the data without detailed modeling of complicated features of the Earth's ionosphere, we propose to measure the curl of the magnetic field at each site. |
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F01.00130: SPUD: SPectroscopy for Ultralight Dark matter Natalie K Velez, Evan R Ritchie, Gabe J Gregory, Thomas Bouley, David J Wineland, Tien-Tien Yu, David T Allcock One of the most important scientific goals of the next decade is to uncover the nature of Dark Matter (DM). Several DM models characterized by a low mass (well below 1 eV) scalar field are thought to be detectable by table-top atomic, molecular, and optical experiments [1]. These candidate DM particles carry a mass small enough such that they behave as a classical coherent field whose interactions with Standard Model particles manifest as fluctuations in the fundamental constants of nature [2]. Spectroscopy experiments are attractive platforms for observing such fluctuations, with the structure of atoms determined largely by the values of the fine structure constant and mass of the electron, with molecular systems benefiting further from additional dependence on nuclear masses, enabling characterization of these DM candidates across multiple channels of interactions via measurement of a single observable. We have designed the experiment SPectroscopy for Ultralight Dark matter (SPUD) that aims to impove the limits on variations of the fundamental constants due to DM as revealed by the variations in the spectra of molecules, allowing for the search of ultralight bosonic DM in the 10-7 to 10-4 eV range. We conduct precision measurement of logarithmic variations in the absorption spectrum to compute bounds on the strength of DM coupling to the Standard Model. This work expands upon previous similar experiments conducted with an Iodine (I2) system by searching at higher mass ranges [3]. |
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F01.00131: Sub-Recoil Cooling on the Meta-Stable Clock-State in Ytterbium Benjamin D Hunt The ability to efficiently cool the atoms’ motion is essential to the accuracy of optical atomic |
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F01.00132: Optical Telecom-Band Clock using Neutral Titanium Atoms Jack Schrott, Scott Eustice, Dmytro Filin, Sergey G Porsev, Charles Cheung, Diego Novoa, Dan M Stamper-Kurn, Marianna Safronova We propose an optical clock based on narrow, spin-forbidden M1 and E2 transitions in lasercooled neutral titanium. These transitions exhibit much smaller black body radiation shifts than those in alkaline earth atoms, small quadratic Zeeman shifts, and have wavelengths in the S, C, and L-bands of fiber-optic telecommunication standards. For the most appealing and experimentally realizable clock transition at 1549nm, we have identified several convenient magic trapping wavelengths (781nm, 789nm, 1037nm). We calculate lifetimes; transition matrix elements; dynamic scalar, vector, and tensor polarizabilities; and black body radiation shifts of the clock transitions. We also calculate the line strengths and branching ratios of the transitions used for laser cooling. Finally, we identify challenges posed by magnetic dipole-dipole interactions and describe an approach to overcome them. We also briefly discuss technical details of building an ultracold Ti experiment. Direct access to a telecommunications-band atomic frequency standard will aid the deployment of optical clock networks and clock comparisons over long distances. |
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F01.00133: A Cesium lattice optical clock (CLOC) Jacob Scott, Shimon Kolkowitz, Mark Saffman We present progress towards a Cesium Lattice Optical Clock (CLOC)[1]. The CLOC is a spatially compact clock that utilizes the 685nm quadrupole line in Cs to implement an opticla frequency clock. The CLOC involves trapping Cs atoms in a 3D array with a magic trap wavelength at 803nm, using a hole array mask[2] to generate trap sites. Here, we present the design and progress towards this goal, primarily focusing on progress with excitation/manipulation/cooling on the 685nm line. |
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F01.00134: Direct Observation of Stability Enhancement in a Spin-squeezed Strontium Optical Lattice Clock Comparison Yee Ming Tso, Maya Miklos, John M Robinson, Joonseok Hur, James K Thompson, Jun Ye Current state-of-the-art atomic clocks are reaching the fundamental precision limit set by the quantum projection noise (QPN) of uncorrelated atoms. The incorporation of spin-squeezing in atomic samples enables clocks to perform below the QPN limit. Here, we present the recent experimental progress of our spin-squeezed strontium optical lattice clock. We generate spin-squeezed states of atoms via cavity QED-based quantum nondemolition measurements. In addition, a movable optical lattice enables spin squeezing of two spatially separate atomic sub-ensembles that are independently addressed by the cavity. In a direct, synchronous clock comparison between the two spin-squeezed atomic sub-ensembles, we measure a clock stability enhancement of 2.0(3) dB beyond the QPN-limit and reach a measurement precision at the 10^-17 level [1]. |
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F01.00135: Ultrastable microwave transfer of cesium frequency standard over 20 km of optical fiber Jacob B VanArsdale, Michael A Lombardi, Glenn K Nelson, Jeffrey A Sherman, Dylan C Yost, Samuel M Brewer Precise absolute frequency measurements of transitions in atomic, ionic, and molecular systems provide an excellent means for stringent tests of fundamental physics. In many cases, however, the accuracy of an optical frequency measurement is limited by the accuracy of the local, commercial frequency reference used in the experiment. To address this limitation, we have established a dark optical fiber link between Colorado State University (CSU) and the National Institute of Standards and Technology (NIST) radio station, WWV, to transfer the microwave signal generated by an ensemble of cesium beam atomic clocks located at the radio station. This frequency transfer scheme allows the timescale at WWV, which is referenced to UTC(NIST), to act as the primary frequency reference for measurements taking place at CSU. The link was established using pre-existing, commercially available telecommunications fibers. We have implemented an active pathlength stabilization system to eliminate frequency drifts due to fluctuations in the optical path length of the fiber. We have also compared stabilization schemes which involve fiber noise cancellation using a single fiber and a pair of fibers in the same bundle. The transferred cesium signal is measured against a local rubidium reference and a frequency comb locked to a ULE cavity as tests of the stability of the link. |
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F01.00136: Spin-exchange rate coefficients in Rb-Xe and Cs-Xe systems using repolarization Zahra Armanfard, Adnan I Nahlawi, Brian T Saam We measure and compare the spin-exchange rate coefficients Κse for Rb and Cs in a He (94%)-N2 (3%)-Xe (3%) gas mixture, similar to that used in flow-through Xe polarizers. The measurements are crucial to understanding which alkali-metal is the best partner for polarizing 129Xe; they are carried out in two matched sets (one each for Rb and Cs) of four sealed vapor cells. Combining these results with our recent spin-destruction rate results from the same samples points to which alkali-metal is intrinsically most efficient for producing large quantities of hyperpolarized Xe for applications such as medical imaging. We employed the repolarization method [1,2], where Κse = (PAεγA) / (PXe[Xe]-εPA[Xe]), and where ε is the nuclear slowing-down factor. Using optically detected pulsed EPR of the alkali-metal hyperfine structure, we measured the alkali-metal polarization PA , the alkali-metal spin-destruction rate γA due to Xe, and the 129Xe polarization PXe . The spin-destruction rate is measured “in the dark” at long delay times, in order to isolate the slowest polarization-decay component; at even longer delay times, when PA reaches a steady state due to the non-zero PXe , the so-called “back-polarization” of the alkali-metal can be determined and then calibrated by examining hyperfine peak ratios at much higher PA during active optical pumping. We calculated PXe[Xe] by using the known Rb-Xe and Cs-Xe enhancement factors (κ0)Rb and (κ0)Cs [3] and measuring the respective alkali-metal EPR frequency shifts due to polarized 129Xe. The repolarization method has the advantage of not requiring a determination of the alkali-metal number density. [1] R.K. Ghosh and M.V. Romalis, Phys. Rev. A 81, 043415 (2010); [2] B. Chann, et al., Phys. Rev. A 66, 032703 (2002); [3] S. Zou, et al., Phys. Rev. A 106, 012801 (2022). |
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F01.00137: Yb Magnetometer Mario A Duenas, Tina Narong, Josh Tong The group I am working with is designing building and testing a Yb atomic magnetometer, and currently estimating performances for their atomic magnetometer. These atomic magnetometers can be used to precisely measure magnetic vector gradients within a volume of space. We ran our Yb magnetometer experiment and observed some unexplained structures form our fluorescence images. We theorized that our polarized laser field is off axis from our applied magnetic field or there are external magnetic fields coming from different axis that are interacting with our Yb atom. Using a three-axis probe magnetometer we measured the local magnetic field around five sides of our cube, where our atoms are located. From these measurements we concluded there is a local source of magnetic field present which could have cause perturbations during our experiment. These external magnetic fields are believed to be coming from our Zeeman slower system. We decided to assemble 4 4.5x4.5” square Helmholtz coils, one 10” square coil, and one solenoid coil to have local control/cancel the magnetic field around our cube. |
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F01.00138: Ramsey-Scheme 3He-21Ne Comagnetometer with Finite-Field SERF 87Rb Magnetometer Readout Jingyao Wang, Johannes J van de Wetering, William A Terrano, Michael V Romalis Noble-gas comagnetometer systems take advantage of the subtraction of common systematic effects by comparing multiple polarized nuclear spin species with long spin coherence time, and demonstrated high sensitivity to spin-energy splittings originating from various spin interactions, such as inertial rotation and new physics beyond the standard model like EDM and axion dark matter. We develop a Ramsey-scheme 3He-21Ne comagnetometer with finite-field SERF 87Rb magnetometer readout based on a former 3He-129Xe-87Rb system [PRL, 120, 033401 (2018)]. 21Ne is favored over 129Xe for its much longer spin coherence time, and smaller frequency shifts due to both Fermi-contact interaction with 87Rb and contact dipolar interation with 3He. A Ramsey pulse sequence is implemented to limit signal amplitude within the 87Rb magnetometer's dynamic range without compromising on signal-to-noise ratio(SNR), and to improve the statistical sensitivity of frequency measurements. After the nuclear spins are polarized by spin-exchange with Rb vapor optically pumped parallel to an applied bias field, we turn off lasers, actively depolarize Rb, and apply the π/2 pulse - free evolution- π/2 pulse Ramsey sequence to both nuclear spin species in the dark. Pump and probe lasers are turned back on afterwards to read residual precession signals at the nuclear spins' respective Larmor frequencies, whose amplitudes are proportional to the difference between applied pulse frequencies and Larmor frequencies in the bias field. With our setup's current SNR and spin coherence times we project a sub-100 pHz frequency resolution after integration for 24 hours for a sequence optimized with Cramér–Rao lower bound calculations. |
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F01.00139: Compact apparatus for an atom-chip gyroscope Marybeth M Beydler, Zekun Chu, Edward R Moan, Cass A Sackett Sagnac atom interferometers are a promising technique for high-performance rotation sensing, with potential applications for inertial navigation. The use of trapped atoms for the interferometer avoids the need for long free-fall distances that would be incompatible with a navigation apparatus. We have previously demonstrated a dual Sagnac interferometer using Bose-condensed atoms in a time-orbiting potential trap, with an enclosed area of 8.2mm2 and corresponding rotation sensitivity of 6x10-7 rad/s at shot-noise limited detection. A limiting factor in the development and deployment of atom interferometer gyroscopes is their large size. We report on the design and progress of a compact version of the experiment using a novel type of atom chip for the time-orbiting potential trap. The compact system uses a volume of only fifty liters for all optics, vacuum chamber and magnetic coils, and the chip should allow a factor of ten improvement in operation rate. |
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F01.00140: Utilising Atom Interferometers for Dark Matter Detection Daniel Derr, Enno Giese Since the internal structure of atoms is possibly sensitive to dark matter (DM), atomic clocks may serve as suitable DM detectors. Additionally, atomic clocks provide a platform for detecting violations of the Einstein equivalence principle (EEP), e. g. universality of clock rates or universality of the gravitational redshift. |
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F01.00141: Development of a Microwave Atom Chip for AC Zeeman Trapping William Miyahira, Jordan Shields, Cate Sturner, Seth Aubin We present work on the development of a microwave atom chip to generate AC Zeeman (ACZ) potentials for trapping and manipulation of ultra-cold atoms. ACZ potentials have applications in quantum gates, 1D many-body physics, and atom interferometry for precision measurements. Our scheme uses overlapping fields generated by RF and microwave AC currents in parallel microstrip transmission lines to produce minima in circularly polarized magnetic near-fields to confine the atoms. Axial confinement and translation are accomplished using a microwave lattice based on the ACZ or AC Stark effect. Wires below the chip allow for DC trapping. ACZ potentials are spin-specific, can be operated at any arbitrary magnetic field, and are expected to suppress roughness in the trapping potential caused by imperfections in atom chip manufacturing. We present simulations and test results for a novel broadband coupler for interfacing between SMA cables and the micro-fabricated atom chip traces. This coupler uses a tapered microstrip wedge to maintain 50 Ω impedance over a broad frequency range, with large-scale prototypes operating out to 9 GHz. This broadband behavior is useful for generating the microwave lattice and allows for the targeting of other atomic isotopes. To generate the phase-controlled microwaves needed for trapping, we have constructed an ultra-low phase noise source at 6.8 GHz based on IQ modulation with relative phase control between channels and 50 MHz of scan range. |
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F01.00142: Towards Mapping Gravity and High-order Derivatives with a Compact Atom Interferometer Timothy Nguyen, Hanbo Yang, Guanghui Su, Shi Wang, Jose R Dominguez, Mariam Mchedlidze, Xuejian Wu
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F01.00143: Towards atom interferometry with atoms around an optical nanofiber Guanghui Su, Hanbo Yang, Timothy Nguyen, Shi Wang, Nami Uchida, Xuejian Wu
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F01.00144: Improved Bragg splitting of Bose-Einstein condensates into high-order momenta wave-packets Ceren Uzun, Saurabh Pandey, Vashisth Tiwari, Katarzyna Krzyzanowska, Malcolm G Boshier Important precision measurements including rotations can be realized using matter-wave interferometers. Our guided Sagnac interferometer cycle starts with coherent splitting of a stationary Bose-Einstein condensate (BEC) into non-zero momenta wave-packets. A way to improve the sensitivity of such an interferometer is to utilize wave-packets with higher momenta that enclose a bigger area at recombination. Recently, we reported preliminary results of splitting Bose-Einstein condensates into high-order target momentum states using optical standing-wave Bragg pulse sequences of various shapes. In this work, we report on the improvements that are made to the Bragg-splitting experiment design that enabled higher splitting fidelities. We also numerically explore the high-order momentum splitting dynamics with different pulse shapes using improved one-dimensional Gross-Pitaevskii (GPE) simulations which will be compared to the splitting experiments. We will further discuss the improvements to the experimental apparatus to realize better quality experimental data. |
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F01.00145: Optically-trapped and cooled nanoparticles as scanning surface force sensors at sub-micron distances Eduardo Alejandro, Cris A Montoya, William Eom, Daniel Grass, Nicolas Clarisse, Apryl Witherspoon, Andrew A Geraci Optically levitated nanospheres in vacuum serve as a powerful probe for precision force sensing due to their excellent decoupling from the environment. We describe a method for 3-D scanning force sensing of a conducting surface with a levitated nanosphere. 3-D control of a nanosphere near a conductive surface could enable attonewton-level scanning force microscopy, precision tests of non-Newtonian gravity at micron distances, measurement of Casimir forces as well as further study of patch potentials that contribute to the background. We trap a ~170 nm diameter silica nanosphere with an optical tweezer trap, and transfer it into an optical lattice by retroreflecting the tweezer beam with a gold-coated silicon surface. The nanosphere can be trapped axially at discrete positions from a quarter of the laser's wavelength to tens of microns away from the conducting surface, while a piezo-driven mirror allows us to scan tens of microns in the remaining two dimensions parallel to the surface. Lastly, we demonstrate attonewton-level force sensing independent of the nanosphere's position relative to the conducting surface. Additionally, we also discuss methods we are developing to sympathetically cool the motion of our nanoparticles using laser cooled atoms. Such ultra-cold nanoparticles may serve as a matter wave based sensor of short-range surface forces |
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F01.00146: Optical Trapping of Microdisks for Detection of Gravitational Waves Shelby Klomp, Aaron Wang, George P Winstone, Greg Felsted, Andrew S Laeuger, Daniel Grass, Jacob Sprague, Peter Pauzauskie, Nancy Aggarwal, Shane L Larson, Vicky Kalogera, Andrew A Geraci We present an update on the Levitated Sensor Detector (LSD) project for detection of high frequency (10-100kHz) gravitational waves above the region previously probed by LIGO. Motivated sources of gravitational waves in this frequency range include superradiance from QCD axion clouds around black holes. The experiment will make use of optically-levitated flat dielectric micro-scale particles as force sensors with the advantage of reduced photon recoil heating. We therefore discuss initial experimental trapping and cooling results of high-aspect-ratio NaYF4 hexagonal prisms, and we examine the experimental progress of the 1-meter LSD prototype that is in construction at Northwestern University. |
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F01.00147: Towards a test of ultrashort-range forces using a strontium molecular clock Brandon Iritani, Perry Zhou, Emily Tiberi, Kon H Leung, Mateusz Borkowski, Tanya Zelevinsky Homonuclear diatomic molecules provide a rich platform for metrology as well as tests of quantum chemistry and fundamental physics, including unique advantages in searches for fifth forces and tests of the temporal variation of fundamental constants. We have completed a measurement of the largest vibrational transition in the 88Sr2 isotopologue and performed its full systematic characterization. We discuss progress toward improved clock precision, including the potential for state-selective suppression of blackbody radiation (BBR) shifts and steps toward reducing systematic uncertainties and increasing the duration of coherent clock-state manipulation. We also discuss using clock transitions in bosonic isotopologues of strontium dimers in order to place constraints on ultrashort-range forces at the nanometer scale. |
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F01.00148: Preliminary studies towards implementing quantum nondemolition spin detection in radium electric dipole moment measurements Karina Martirosova, Gordon Arrowsmith-Kron, Jaideep Singh, Michael N Bishof, Peter Mueller, Kevin G Bailey, Tom O'Connor The electric dipole moment (EDM) is an intrinsic property of atomic systems that, if it exists, directly violates time reversal symmetry (T). T violation implies charge-parity symmetry (CP) violation and the discovery of additional CP violation is necessary to explain the matter-antimatter asymmetry in the universe. A recent EDM measurement in Yb-171 demonstrated a novel spin-state detection technique that utilizes multiple laser wavelengths to inhibit decoherence via state dressing and achieved spin-state detection efficiency of 50%[T. A. Zheng et al., Phys Rev Lett. 129, 083001 (2022)]. We will report on the benefit and feasibility of adapting this technique to radium atoms. Radium, because of its highly deformed “pear-shaped” nucleus, has enhanced sensitivity to new physics compared to nearly spherical nuclei such as Yb-171 and Hg-199. This work is supported the U.S. DOE, Office of Science, Office of Nuclear Physics, under contracts DE-AC02-06CH11357 and DE-SC0019455 and is based upon work supported by the Department of Energy National Nuclear Security Administration through the Nuclear Science and Security Consortium under Award Number DE-NA0003996. |
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F01.00149: Ultrasensitive Force Measurements with Optically Levitated Nanoparticles Andrew Poverman, Nia Burrell, Chethn Galla, Andrew A Geraci The large mechanical quality factor of optically levitated dielectric particles makes them an ideal |
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F01.00150: Precision measurement of Coriolis force with 2D Penning trapped ion crystal Yao Chen, Libo Zhao, Zhuangde Jiang The precision measurement of Coriolis force finds application in rotation measurement. In the non-inertial reference, the Coriolis force caused by the moving of proof of mass in the perpendicular direction. Here, we are focus on the Coriolis force measurement in a quantum harmonic oscillator. The vibration of the ions forms a harmonic oscillator while the Coriolis force is formed in the vertical direction. To configure this type of rotation measurement, we studied the 2D Penning trapped ions. In the system, the magnetron motion of the ions is controlled by rotating wall driving. The Coriolis force induced perpendicular vibration which is measured by an optical method. Optical dipole force entangled the position of the oscillator with the internal degree of freedom of the ions. Precision measurement of the amplitude of the oscillator is required. To let the force response as large as possible, we studied the shape of the ions under different rotating wall driving frequencies. We need to let the rotating wall driving frequency be equal to the axial resonance frequency and thus the amplitude of the ions can be very large. Note that under resonance, we have an oscillator with Q factor of 106. We studied the sensitivity limit of the quantum vibration gyroscope and will talk about future application of the gyroscope. |
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F01.00151: GPS.ELF: Search for exotic low-mass field emission from the binary neutron star merger (GW170817) using GPS atomic clocks Arko P Sen, Colin Bradley, Conner Dailey, Kalia Pfeffer, Paul Ries, Geoffrey Blewitt, Andrei P Derevianko Exotic bosonic fields are viable dark matter candidates, and they appear as potential solutions to the strong-CP and hierarchy problems. Such fields can be potentially emitted from powerful astrophysical events, such as binary neutron star and binary black hole mergers. This leads to an intriguing possibility for a novel, exotic physics, modality in multi-messenger astronomy [Nature Astronomy 5, 150 (2021)]. We present the progress of our search for such feebly interacting exotic low-mass field. As these bosonic fields interact feebly with the standard model particles and fields, precision quantum sensors are an ideal candidate for its detection. We use the data from atomic clocks of the Global Positioning System. The search is carried out by comparing the clock excess noise before and after the LIGO gravitational wave trigger. Our search focuses on the August 17, 2017 GW170817 binary neutron star merger event. |
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F01.00152: Trapped ion's photon transmission over 11 km over existing in-ground telecom fiber network Matthew Diaz, Michael Kwan, John Hannegan, James Siverns, Uday Saha, Edo Waks, Qudsia Quraishi The transmission through existing telecom fiber infrastructure of photons emitted from quantum memories offers a means for implementing quantum information protocols between remotely located nodes. Trapped ions are excellent quantum networking nodes [1, 2] but their photon transmission distance in free space or in telecom fibers has been limited until recent integration with quantum frequency conversion (QFC) techniques [3, 4]. Here, we send photons emitted from a trapped 138Ba+ ion through an 11.2 km loop of optical telecom fiber linking our Army Research Lab quantum networking node [5] located at the University of Maryland (UMD) with the UMD Discovery Lab located 4.8 km driving-distance away. We perform two stages of QFC to convert 493 nm photons to telecom photons within the o-band regime [6] and show the preservation of the photon’s temporal profile before and after transmission. Prior long-haul networking experiments employed fiber spools [7]. Implementation within telecom fiber infrastructures [8, 9] laid in/above ground offers in-situ network testing. Our work is the longest known transmission of photons from a trapped ion over such a telecom fiber network and serves as a testbed for quantum networking protocols. |
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