Bulletin of the American Physical Society
51st Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 65, Number 4
Monday–Friday, June 1–5, 2020; Portland, Oregon
Session J06: Atom and Matter-Wave Optics and InterferometersLive
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Chair: Alejandra Collopy, NIST Room: E141-142 |
Wednesday, June 3, 2020 2:00PM - 2:12PM Live |
J06.00001: Matter-Wave Interferometry with Helium Atoms in Low-Angular-Momentum Rydberg States Jake Tommey, Stephen Hogan Atoms in Rydberg states with high principal quantum number can possess large induced electric dipole moments which allow forces to be exerted on them using inhomogeneous electric fields. For atoms prepared in superpositions of Rydberg states with different electric dipole moments these forces can be exploited to realize an electric analogue of the Stern-Gerlach matter-wave interferometer. In this talk we will describe experiments in which helium atoms traveling in pulsed supersonic beams were laser photoexcited to the triplet $|56s\rangle$ Rydberg state. They were then prepared in a superposition of the $|56s\rangle$ and $|57s\rangle$ states by a pulse of microwave radiation resonant with the two-photon transition between these states. In this internal-state superposition they were subjected to a sequence of electric field gradient and further microwave pulses to realize an electric Rydberg-atom matter-wave interferometer with internal-state labeling. The Rydberg states used in the experiments had dimensions on the order of 500 nm, given by the spatial extent of the Rydberg electron charge distribution. This work opens new opportunities for studies of quantum phases for particles with large electric dipole moments, and gravity measurements with Rydberg positronium atoms. [Preview Abstract] |
Wednesday, June 3, 2020 2:12PM - 2:24PM Live |
J06.00002: Twin-lattice atom interferometers using thousands of photon recoils Sven Abend, Martina Gebbe, Matthias Gersemann, Christian Schubert, Ernst M. Rasel Atom interferometry offers an interesting perspective for the detection of gravitational waves in the frequency band between eLISA and Advanced LIGO. A key feature to reach the targeted sensitivities for these devices is large momentum transfer. Optical lattices are ideal tools to transfer large number of photon recoils onto atoms. We demonstrate twin-lattice atom interferometers with up to 1632 photon recoils at a maximum splitting of 408 photon recoils, which is to our best knowledge the largest in an interferometer reported so far. To reach these large momentum splittings while maintaining interferometric contrast, we utilize delta-kick collimated Bose-Einstein condensates. The main cause for loss of contrast in these interferometers are distortion on the lattice light field. In our setup we can verify by simulations, that these distortions are caused by aperture effects of the Gaussian beam and show an increased contrast by a factor of 3. We study the influence of these light field distortions and show the implementation of a top-hat-shaped laser beam to surpass our current limitations. [Preview Abstract] |
Wednesday, June 3, 2020 2:24PM - 2:36PM Live |
J06.00003: Progress Towards an Ultracold Trapped Atom Interferometer Shuangli Du, Andrew Rotunno, Douglas Beringer, Seth Aubin Atom interferometers are extremely sensitive quantum measurement devices and are well suited for precision gravimetry. We present our progress in developing a new type of atom interferometer based on ultracold trapped atoms. The main benefit of a trapped atom interferometer is that, in principle, it can have a long phase integration time, which leads to a linear improvement in sensitivity over time. The development of our interferometer requires several proof-of-principle milestones to be accomplished. Notably, we have already reached our first milestone: we have implemented a trapped atom Ramsey interferometer with a coherence time in the 100 ms range. Our interferometer design is based on a Ramsey scheme whereby two different spin states are spatially separated by applying a microwave-based spin-dependent force generated by the AC Zeeman effect. The next milestone is to apply a spin-specific energy shift to one of the interferometer paths. For the final milestone, we will convert this energy shift into a force that will spatially separate the two interferometer paths. Our proof-of-principle interferometer is a first step towards building a compact, high precision gravimeter for remote detection of subterranean features. [Preview Abstract] |
Wednesday, June 3, 2020 2:36PM - 2:48PM Live |
J06.00004: Integrated atomic waveguides for atom interferometry (AI) William Kindel, Adrian Orozco, Katherine Musick, Christina Dallo, Andrew Starbuck, Andrew Leenheer, Yuan-Yu Jau, Grant Biedermann, Michael Gehl, Jongmin Lee We present our progress developing integrated photonic waveguides for guided atom interferometry (AI). This is a promising platform for position, navigation and timing (PNT) sensors because atom interferometry is among the most sensitive techniques for inertial detection, and these integrated waveguides provide new paths for developing scalable and modular devices with low size, weight and power (SWaP) requirements. However, prohibitive technical challenges remain. For instance, atoms have yet to be trapped in the evanescent fields of integrated waveguides due to limited heat dissipation of these guides in vacuum.~To address these challenges, we are developing alumina membrane rib waveguides with engineered heat dissipation. We present our designs and power handling of these suspended waveguide bridges and our progress towards trapping Cs atoms and performing guided atom interferometry on them. \textit{Sandia National Laboratories is a multimission laboratory managed and operated by National Technology {\&} Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA0003525.} [Preview Abstract] |
Wednesday, June 3, 2020 2:48PM - 3:00PM Live |
J06.00005: General Analytic Theory for Bragg Atom Interferometry Jan-Niclas Siemss, Florian Fitzek, Sven Abend, Ernst M. Rasel, Naceur Gaaloul, Klemens Hammerer Bragg diffraction is a cornerstone of light-pulse atom interferometry. High-fidelity Bragg pulses operate in the quasi-Bragg regime in which no simple analytic description of the diffraction process exists. We develop an analytic theory for such pulses based on the adiabatic theorem. Indeed, we show that for the widely adapted case of Gaussian temporal pulse shapes Bragg diffraction is an adiabatic process in the sense of the adiabatic theorem. Our model provides an intuitive understanding of the Bragg condition and includes corrections to the adiabatic evolution up to first order. Furthermore, we include the effects of linear Doppler shifts applicable to narrow atomic velocity distributions on the scale of the photon recoil of the optical lattice. We verify our scattering theory by comparing it to an exact numeric integration of the Schroedinger equation for Gaussian pulses diffracting $4,6,8$ and $10$ photon recoils and show that non-adiabatic processes are accurately described via Landau-Zener physics. Our formalism provides an analytic framework to study systematic effects as well as limitations to the sensitivity of atom interferometers employing Bragg optics that arise due to a non-ideal diffraction process. [Preview Abstract] |
Wednesday, June 3, 2020 3:00PM - 3:12PM Live |
J06.00006: Atom optics for excited-band Bloch oscillations and vertical contrast interferometry Daniel Gochnauer, Tahiyat Rahman, Anna Wirth, Katherine McAlpine, Subhadeep Gupta Our ytterbium (Yb) Bose-Einstein condensate (BEC) contrast interferometer (CI) operates with standing-wave light pulses and is designed to make a precision measurement of the fine structure constant, $\alpha$, via a photon recoil measurement. We previously demonstrated a method to determine atomic band structure in an optical lattice through the analysis of the consequent lattice-induced phase shifts in our CI [1], which has led to a technique for the minimization of such phase shifts through particular usage of Bloch oscillations (BOs) in excited bands of an optical lattice [2]. We will report on the application of this method to demonstrate interferometry with up to $40\hbar k$ momenta supplied by BOs and also discuss extensions of this technique to larger momentum transfer and adaptations towards metrological applications of atom interferometry such as a measurement of $\alpha$. To this end, we will also report on our progress towards a new vertically oriented CI to increase the interferometer time and thus sensitivity for such applications. [1] D. Gochnauer et al, Phys Rev A 100, 043611 (2019). [2] K. McAlpine et al, arXiv:1912.08902 [Preview Abstract] |
Wednesday, June 3, 2020 3:12PM - 3:24PM Live |
J06.00007: Large Momentum Transfer Point Source Atom Interferometer Selim Shahriar, Jinyang Li, Wayne Huang, Gregorio Rabelo, Timothy Kovachy, Mohamed Fouda In a point source atom interferometer (PSAI), the magnitude of rotation can be inferred by carrying out a two dimensional Fourier Transform (FT) of the spatial distribution of atoms in one of the two quantum states. The locations of the peaks in the FT yields the magnitude and the direction of the rotation vector normal to the wavevectors of the light pulses. The sensitivity of such a rotation sensor, defined as the minimum measurable rate of rotation, is inversely proportional to the magnitude of the momentum imparted to the atoms. For a conventional PSAI, this momentum equals the sum of the momenta of the two photons exciting the Raman transition. This limit can be overcome by employing the technique of large momentum transfer using additional Raman pulses that couple two hyperfine ground states, for example. Ideally, if the amount of momentum imparted is N times that of a conventional PSAI, the sensitivity improves by a factor of N. However, because of increasing Raman detuning, the contrast in the fringes starts decreasing with increasing N. Beyond an optimal value of N, the sensitivity starts decreasing. The optimal value of N depends on the value of the effective Rabi frequency of the Raman transition. We will present results of a detailed numerical model, employing fully quantized wavepackets for the atoms, to illustrate this behavior. We will also present experimental results obtained for such a PSAI employing Rb-85 atoms. [Preview Abstract] |
Wednesday, June 3, 2020 3:24PM - 3:36PM Live |
J06.00008: Persistent Flow in Fermionic Superfluid Rings Kevin Wright, Yanping Cai, Daniel Allman, Parth Sabharwal We have created and detected persistent flow in an ultracold Fermi gas for the first time. We confine the gas to a trapping potential that is overall annular in shape, using time dependent perturbations of the potential such as a moving tunnel junction to realize a ``circuit'' that allows us to control the circulation state. We have observed that the stability of persistent currents varies with the system geometry and other factors that affect fluctuations and dissipation in the system. We will report on efforts to use this system to obtain useful information about the transport properties of fermionic quantum gases. [Preview Abstract] |
Wednesday, June 3, 2020 3:36PM - 3:48PM On Demand |
J06.00009: Improving Ramsey interferometry using STIRAP Branden Tatasciore, Frank Narducci We have been investigating Ramsey and spin-echo interferometry in continuous beam atom interferometers. Atoms experience pulses of light due to their transit time through Raman fields that are also on continuously. We have earlier demonstrated that the atoms in our system, which originate from a two-dimensional magneto-optical trap to reduce their transverse temperature, also have a low average longitudinal velocity. However, they still have a spread in their velocities which leads to pulse errors. Our earlier modeling and experiments have shown that averaging over the longitudinal velocity leads to the removal of all the Ramsey fringes except the central one. Stimulated Raman adiabatic passage, on the other hand, is a more robust method of coherently transferring population and should be more robust to pulse errors and therefore to velocity averaging. Our preliminary modeling shows this to be true in our system. In this talk, we present the results of the modeling of our system and discuss experimental implementations and considerations. [Preview Abstract] |
Wednesday, June 3, 2020 3:48PM - 4:00PM |
J06.00010: Controlling a Bose-Einstein Condensate in Space: Towards Space Based Atom Interferometry Nicholas Bigelow, Naceur Gaaloul, Matthias Meister, Annie Pichery, Waldemar Herr, Ernst Rasel, Wolfgang Schleich, Robin Corgier, Patrick Boegel, Robert Thompson, Jason Williams We describe recent experimental work aboard the International Space Station using the NASA facility CAL, the Cold Atom Laboratory. We will describe significant progress on quantum gas manipulation in microgravity using short cuts to adiabaticity (STA) protocols and on delta kick cooling (DKC) in Space. We describe our success in the context of enabling high performance atom interferometry in space. [Preview Abstract] |
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