Gravitational caustics in an atom laser

Typically discussed in the context of optics, caustics are envelopes of classical trajectories (rays) where the density of states diverges, resulting in pronounced observable features such as bright points, curves, and extended networks of patterns. Here, we generate caustics in the matter waves of an atom laser, providing a striking experimental example of catastrophe theory applied to atom optics in an accelerated (gravitational) reference frame. We showcase caustics formed by individual attractive and repulsive potentials, and present an example of a network generated by multiple potentials. Exploiting internal atomic states, we demonstrate fluid-flow tracing as another tool of this flexible experimental platform. The effective gravity experienced by the atoms can be tuned with magnetic gradients, forming caustics analogous to those produced by gravitational lensing. From a more applied point of view, atom optics affords perspectives for metrology, atom interferometry, and nanofabrication. Caustics in this context may lead to quantum innovations as they are an inherently robust way of manipulating matter waves.

Preface

General Information This volume of the Journal is devoted to the IX International Symposium and Young Scientists School “Modern Problems of Laser Physics” (MPLP-2021)1 that was held in Novosibirsk, Russia, 22-28 August 2021. The MPLP symposium has a long history starting from 1995 and gathers scientists from many courtiers who carrying out their researches in the forefront of laser physics, quantum metrology and high-resolution spectroscopy, physics of ultracold atoms, molecules and ions, atom optics, ultrafast phenomena and attoscience, quantum optics and information, nonlinear optics and applications of laser radiation from THz to UV radiation ranges in medicine, geophysics, chemistry and microbiology. This year the sessions devoted to advances in laboratory space plasma physics with lasers was also included in the list of topics of MPLP symposium. The Scientific Program of MPLP-2021 includes invited and oral talks selected from contributed papers, as well as several Poster Sessions. A Scientific School for Young Scientists was also take place during the Symposium. Following the tradition of MPLP Symposia, the scientific program comprises single sessions of invited and oral presentations for each topic, running sequentially. This year online access to MPLP was provided for participants who can’t attend the symposium in-person and many of the invited talks were done online. List of Organizers, Committees, Chairman of the Symposium, Invited and Oral Speakers, School for Young Scientists and Results are available in this pdf.

Quantum sensors for space-borne earth observation

<p>Atom interferometry enables quantum sensors for absolute measurements of gravity (1) and gravity gradients (2). The combination with classical sensors can be exploited to suppress vibration noise in the interferometer, extend the dynamic range, or to remove the drift from the classical device (3). These features motivate novel sensor and mission concepts for space-borne earth observation e.g. with quantum gradiometers (4) or hybridised atom interferometers (5). We will discuss developments of atom optics and atom interferometry in microgravity in the context of future quantum sensors (6) and outline the perspectives for applications in space (4,5).</p><p>The presented work is supported by by the CRC 1227 DQmat within the projects B07 and B09, the CRC 1464 TerraQ within the projects A01, A02 and A03, by "Niedersächsisches Vorab" through "Förderung von Wissenschaft und Technik in Forschung und Lehre" for the initial funding of research in the new DLR-SI Institute, and through the "Quantum and Nano- Metrology (QUANOMET)" initiative within the project QT3.</p><p>(1) V. Ménoret et al., Scientific Reports 8, 12300, 2018; A. Trimeche et al., Phys. Rev. Appl. 7, 034016, 2017; C. Freier et al., J. of Phys.: Conf. Series 723, 012050, 2016; A. Louchet-Chauvet et al., New J. Phys. 13, 065026, 2011; A. Peters et al., Nature 400, 849, 1999.</p><p>(2) P. Asenbaum et al., Phys. Rev. Lett. 118, 183602, 2017; M. J. Snadden et al., Phys. Rev. Lett. 81, 971, 1998.</p><p>(3) L. Richardson et al., Comm. Phys. 3, 208, 2020; P. Cheiney et al., Phys. Rev. Applied 10, 034030, 2018; J. Lautier et al., Appl. Phys. Lett. 105, 144102, 2014.</p><p>(4) A. Trimeche et al., Class. Quantum Grav. 36, 215004, 2019; K. Douch et al., Adv. Space. Res. 61, 1301, 2018.</p><p>(5) T. Lévèque et al., arXiv:2011.03382; S. Chiow et al., Phys. Rev. A 92, 063613, 2015.</p><p>(6) M. Lachmann et al., arXiv:2101.00972; K. Frye et al., EPJ Quant. Technol. 8, 1, 2021; D. Becker et al., Nature 562, 391, 2018; J. Rudolph et al., New J. Phys. 17, 065001, 2015; H. Müntinga et al., Phys. Rev. Lett. 110, 093602 , 2013.</p>

The Bose-Einstein Condensate and Cold Atom Laboratory

Microgravity eases several constraints limiting experiments with ultracold and condensed atoms on ground. It enables extended times of flight without suspension and eliminates the gravitational sag for trapped atoms. These advantages motivated numerous initiatives to adapt and operate experimental setups on microgravity platforms. We describe the design of the payload, motivations for design choices, and capabilities of the Bose-Einstein Condensate and Cold Atom Laboratory (BECCAL), a NASA-DLR collaboration. BECCAL builds on the heritage of previous devices operated in microgravity, features rubidium and potassium, multiple options for magnetic and optical trapping, different methods for coherent manipulation, and will offer new perspectives for experiments on quantum optics, atom optics, and atom interferometry in the unique microgravity environment on board the International Space Station.

Resonant Quantum Kicked Rotor as A Continuous-Time Quantum Walk

We analytically investigate the analogy between a standard continuous-time quantum walk in one dimension and the evolution of the quantum kicked rotor at quantum resonance conditions. We verify that the obtained probability distributions are equal for a suitable choice of the kick strength of the rotor. We further discuss how to engineer the evolution of the walk for dynamically preparing experimentally relevant states. These states are important for future applications of the atom-optics kicked rotor for the realization of ratchets and quantum search.