Transient Supersolid Properties in an Array of Dipolar Quantum Droplets

Abstract

We study theoretically and experimentally the emergence of supersolid properties in a dipolar Bose-Einstein condensate. The theory reveals a ground state phase diagram with three distinct regimes -a regular Bose-Einstein condensate, incoherent and coherent arrays of quantum droplets. The coherent droplets are connected by a background condensate, which leads -in addition to the periodic density modulation -to a robust phase coherence throughout the whole system. We further theoretically demonstrate that we are able to dynamically approach the ground state in our experiment and that its lifetime is only limited by three-body losses. Experimentally we probe and confirm the signatures of the phase diagram by observing the in-situ density modulation as well as the phase coherence using matter wave interference. arXiv:1901.07982v2 [cond-mat.quant-gas]

Thermoelectricity Modeling with Cold Dipole Atoms in Aubry Phase of Optical Lattice

“…We note that for a laser wavelength λ = 564nm, the optical lattice period is = λ/2, and thus for ν ≈ 2.6, we have the Aubry transition at the potential amplitude V A /k B = T A = 0.14 a /k B ≈ 200nK. Such potential amplitude and temperature are well reachable with experimental setups at T ≈ 20nK used in [27].…”

Two-dimensional quantum droplets in dipolar Bose gases

“…Our simulations are carried out for 162 Dy atoms, with typical atom number N=10 4 and a=141a 0 [33] (a 0 being the Bohr radius) which can be controlled via a magnetic Feshbach. Dy atoms in their ground state have a dipolar length r * =130a 0 [23,34]. In this configuration a roton mode is expected to appear.…”

“…The nucleation of this state occurs due to the competition between the roton instability results in local collapses [22], and the LHY fluctuations. It has been suggested that the roton softening combined with the quantum stabilization mechanism opens a new avenue for exploring supersolids [23].…”

Excitation spectrum and supersolidity of a two-leg bosonic ring ladder

“…The concept of supersolidity was first introduced in the context of liquid Helium more than fifty years ago [1,2]. With ultracold atoms, supersolidity has been observed with Bose-Einstein condensates in a cavity [3][4][5][6] as well as in dipolar quantum gases [7][8][9][10]. Both experimental realizations of supersolidity are based on longrange interactions [11], a key ingredient first introduced by Gross [12].…”