Superfluid and supersolid phases in optical lattices in two dimensions

Abstract

Abstract. This work addresses the study of superfluid and supersolid phases of dipolar Fermi molecules lying in a two dimensional space. The prediction of these phases, performed within a mean field analysis, results from proposing a model in which interacting Fermi molecules are confined in a bilayer array of parallel lattices with square symmetry. As a result of the repulsive intralayer and attractive interlayer interactions between dipolar molecules, a checkerboard pattern and a paired superfluid regimes can emerge. The supersolid phase is identified as the spatial coexistence of density ordered and superfluid phases. The model here proposed can be implemented within the current experimental capabilities as a function of the interlayer separation and the application of an external electric field varying the dipolar interaction between molecules.

Bound states and Cooper pairs of molecules in 2D optical lattices bilayer

“…We should stress that the for typical experiments with ultracold molecules, confining them in square optical lattices in 2D, this cartoon represent plausible size of pairs. It is interesting to note functional integral calculations of the BCS state at T = 0 [22] predicts similar values for the binding energy than those here obtained for the two-body problem.…”

“…This result is promising in a double manner, on the one hand, current experiments with ultracold dipolar molecules allow for achieving superfluidity of BCS and bound dimers, and on the other hand, BEC-BCS crossover can be addressed theoretically since the terms defining the many-body Hamiltonian are already set. There exist literature concerning both, the study of dipolar gases at zero and finite temperature in homogeneous environments [17][18][19][20], and analysis taking into account lattice confinements [21,22]. The present analysis dealing with few-body states of fermions is a key ingredient of the many-body systems dealing with the BEC-BCS crossover.…”

Bipolarons in a Bose-Einstein Condensate

“…We calculate this interaction using the diagrammatic scheme illustrated in Fig. 2(b), which simultaneously accounts for arbitrarily strong boson-impurity scattering and the propagation of density waves in the BEC [30,31].…”

Long-Range Interactions and Symmetry Breaking in Quantum Gases through Optical Feedback

“…Alternatively, effective interactions can be induced by another quantum system coupled to the cold atoms. Examples include polaron interactions in degenerate gases [21][22][23] and photon-mediated interactions induced by interfacing atoms with nano-scale photonic structures [24,25] or optical cavities [26][27][28][29][30][31][32][33][34]. Such and similar atom-photon interfaces offer unprecedented control capabilities for the emerging interactions [25,30,34], and provide a unique platform for observing new phases of quantum matter [27-29, 31, 33, 35, 36] and fascinating collective optomechanical phenomena [37][38][39].…”