Bulletin of the American Physical Society
53rd Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 67, Number 7
Monday–Friday, May 30–June 3 2022; Orlando, Florida
Session C09: Dipolar Quantum Gases: Supersolids and Other Novel PhasesRecordings Available
|
Hide Abstracts |
Chair: Brendan Marsh, Stanford University Room: Salon 11/12 |
Tuesday, May 31, 2022 11:00AM - 11:12AM |
C09.00001: Two-dimensional supersolid formation in dipolar Bose-Einstein condensates Thomas Bland, Elena Poli, Claudia Politi, Lauritz Klaus, Matthew A Norcia, Francesca Ferlaino, Luis Santos, Russell N Bisset The long sought-after supersolid phase has recently been observed in dipolar Bose-Einstein condensates, exhibiting global phase coherence and crystalline density structure. While one-dimensional supersolids may be prepared by quenching the local interaction strength, we find that such a procedure in two dimensions leads to a loss of both phase coherence and crystalline order. We develop a finite-temperature stochastic Gross-Pitaevskii theory that includes beyond-meanfield effects to explore the formation process for 2D supersolids, and find that evaporative cooling directly into the supersolid phase produces a robust supersolid in a circular (pancake-shaped) trap. We then experimentally produce a 2D supersolid in a near-circular trap through such an evaporative procedure. Our work provides insight into the process of supersolid formation in 2D, and defines a realistic path to the formation of large two-dimensional supersolid arrays. |
Tuesday, May 31, 2022 11:12AM - 11:24AM |
C09.00002: Self-bound dipolar droplets and supersolids in molecular Bose-Einstein condensates Matthias Schmidt, Lucas Lassablière, Goulven Quéméner, Tim Langen Motivated by our experiments on dipolar magnetic atoms, we numerically study the many-body physics of molecular Bose-Einstein condensates with strong dipole-dipole interactions. We observe the formation of self-bound droplets, and explore phase diagrams that feature a variety of exotic supersolid states. In all of these cases, the large and tunable molecular dipole moments enable the study of unexplored regimes and phenomena, including liquid-like density saturation and universal stability scaling laws for droplets, as well as pattern formation and the limits of droplet supersolidity. We discuss a realistic experimental approach to realize both the required collisional stability of the molecular gases and the independent tunability of their contact and dipolar interaction strengths using a combination of microwave and DC electric fields. Our work provides both a blueprint and a benchmark for near-future experiments with bulk molecular Bose-Einstein condensates. |
Tuesday, May 31, 2022 11:24AM - 11:36AM |
C09.00003: Spin roton in flattened dipolar binary condensates Au-Chen Lee, Danny Baillie, Peter B Blakie A confined dipolar Bose-Einstein condensate can develop a finite-momentum roton instability, which has been observed in recent experiments. Here we consider a flattened two-component dipolar condensate, produced by trapping along one direction. This system exhibits roton instabilities with density- and spin-character. We find that the spin-roton instability marks the transition to a patterned immiscible ground state. We develop a theory for the ground states and excitations of this system and apply this to locating the conditions where the spin-roton forms. |
Tuesday, May 31, 2022 11:36AM - 11:48AM |
C09.00004: Angular oscillations in a 2D supersolid of Dysprosium Lauritz Klaus, Matthew A Norcia, Elena Poli, Claudia Politi, Thomas Bland, Manfred J Mark, Luis Santos, Russell Bisset, Francesca Ferlaino When cooled to quantum degeneracy, gases of dipolar atoms, such as dysprosium, can spontaneously form a modulated many-body state, while simultaneously exhibiting global phase coherence: the supersolid phase. There is great interest in the direct observation of superfluid flow of such a state. For non-modulated superfluids the scissors mode can be directly connected to the moment of inertia and shows an increased frequency compared to classical rigid-body rotation. We probed the response of linear, “zig-zag” and hexagonal supersolid states to small angle rotations and observe a rich excitation spectrum. Our work shows that deducing the moment of inertia from a supersolid state requires knowledge of the full excitation spectrum, motivating further investigation and development of more elaborate excitation schemes to preferentially excite the low frequency modes. |
Tuesday, May 31, 2022 11:48AM - 12:00PM |
C09.00005: Supersolid pattern formation and two-dimensional roton excitations Sean Graham, Jan-Niklas Schmidt, Jens Hertkorn, Mingyang Guo, Fabian Boettcher, Matthias Schmidt, Kevin Ng, Tim Langen, Tilman Pfau, Martin W Zwierlein Dipolar interactions in quantum gases offer a rich landscape of new quantum states to explore. These long-range anisotropic interactions enable the formation of self-organized patterns in quantum gases [1]. Our numerical simulations show that patterns such as labyrinths and honeycombs are within reach and are analogous to patterns found in nature. One special pattern is the supersolid droplets that possess periodic structure and superfluidity. For supersolid droplets, a low-lying Goldstone mode is populated when crossing the phase transition from a condensate, and this mode is directly connected to the finite-momentum roton modes of the system. The existence of a Goldstone mode is proof of superfluidity, a requirement of supersolidity. We observed radial and angular rotons in a round trapping potential by analysing density fluctuations of in situ images [2]. These roton modes are the precursors for two-dimensional supersolids and can be used in future quantum phase searches. |
Tuesday, May 31, 2022 12:00PM - 12:12PM |
C09.00006: Solitons and polarons in ultracold bosonic mixtures Tommaso Macrì, Giacomo Bighin, Andre Cidrim Santos, Luca Salasnich, Alessia Burchianti, Francesco Minardi The realization of multicomponent systems offers a natural playground to observe nonequilibrium effects in a more general framework. Restricting to two-component BECs, one notices already a rich variety of phases in the ground state. In purely repulsive mixtures, one observes a homogeneous superfluid or a phase separation when inter-species repulsion overcomes the intra-species interaction strength. In the attractive regime a series of recent experiments showed the formation of dilute self-bound droplet states in a two-component BEC both in a tight optical waveguide and in free space, closely following the theoretical predictions. In the quasi one-dimensional geometry, upon varying the mean-field interaction from the weakly to the strongly attractive regime, one observes a smooth crossover between bright soliton states and self-bound droplets. In the first part we investigate the quench dynamics of a two component Bose mixture and study the onset of modulational instability, which leads the system far from equilibrium. Analogous to the single-component counterpart, this phenomenon results in the creation of trains of bright solitons. In the second part I will discuss the properties of impurities in uniform and self-bound states of heteronuclear mixtures inspired by recent experiments. Finally, I will focus on the formation of exotic bound states for an impurity interacting with a self-bound droplet. |
Tuesday, May 31, 2022 12:12PM - 12:24PM |
C09.00007: Anisotropic transport coefficients in an ultracold paramagnetic gas. Reuben R Wang Recent theoretical and experimental advances in ultracold lanthanide gases have unlocked new avenues to studying many-body phenomena. One cause of fascinating dynamics, even before quantum degeneracy, arises from the anisotropic dipolar scattering amongst these highly magnetic atoms. The resultant macroscopic effects can thus be studied through transport phenomena in out-of-equilibrium scenarios. To this end, we derive the anisotropic transport coefficients of viscosity and thermal conduction in dilute dipolar gases, using the Chapman-Enskog formalism. Our results open a pathway for control of thermal transport via tuning of the collisional interactions, possible in ultracold atomic systems. |
Tuesday, May 31, 2022 12:24PM - 12:36PM |
C09.00008: Supersolid transition of a dipolar Bose-Einstein condensate in an infinite tube Joseph C Smith, Peter B Blakie, Danny Baillie Supersolids are state of matter that combine crystalline order with superfluid flow and have been realised in Bose-Einstein condensates (BECs) of Dysprosium and Erbium. In this talk we will examine the supersolid transition of a dipolar BEC which has been confined to an infinite tube. We use the beyond mean-field description known as the extended Gross Pitaevskii equation (EGPE). The ground states of the EGPE theory are calculated in a unit cell using a range of techniques to obtained accurate solutions. We show that the supersolid transition can be both first order or second order depending on the average density of the system. |
Tuesday, May 31, 2022 12:36PM - 12:48PM |
C09.00009: Generating long-lived entangled states in multilevel atomic arrays with dipolar interactions Sanaa Agarwal, Asier Pineiro Orioli, Ana Maria Rey We investigate the driven-dissipative dynamics of multilevel atoms in a 1D array interacting via photon-mediated dipole-dipole interactions. Contrary to two-level atoms, we find that multilevel atoms in the low excitation (weak drive) regime can become strongly entangled. These entangled states arise from the action of non-trivial effective many-body jump operators on the ground state manifold. We discuss the role played by elastic and inelastic interactions in generating entanglement as well as the long-lived nature of these states. Our predictions are testable in optical lattice and optical tweezer experiments using the ∼2.7μm transition from 3P2 →3D3 in 87Sr. |
Tuesday, May 31, 2022 12:48PM - 1:00PM |
C09.00010: Disordered bosonic systems with power-law hoppings : a numerical study of phases and conductivity Guido Masella, Nikolay V Prokofiev, Guido Pupillo In the absence of frustration, interacting bosons in the ground state exist either in the superfluid or insulating phases. Superfluidity corresponds to frictionless flow of the matter field, and in optical conductivity is revealed through a distinct δ-functional peak at zero frequency with the amplitude known as the Drude weight. This characteristic low-frequency feature is instead absent in insulating phases, defined by zero static optical conductivity. Here we demonstrate that bosonic particles in disordered one dimensional, d = 1, systems can also exist in a conducting, non-superfluid, phase when their hopping is of the dipolar type, often viewed as short-ranged in d = 1. This phase is characterized by finite static optical conductivity, followed by a broad anti-Drude peak at finite frequencies. Off-diagonal correlations are also unconventional: they feature an integrable algebraic decay for arbitrarily large values of disorder. These results do not fit the description of any known quantum phase and strongly suggest the existence of a novel conducting state of bosonic matter in the ground state. |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700