Ultracold Heteronuclear Molecules and Ferroelectric Superfluids

Abstract

We analyze the possibility of a ferroelectric transition in heteronuclear molecules consisting of Bose-Bose, Bose-Fermi or Fermi-Fermi atom pairs. This transition is characterized by the appearance of a spontaneous electric polarization below a critical temperature. We discuss the existence of a ferroelectric Fermi liquid phase for Fermi molecules and the existence of a ferroelectric superfluid phase for Bose molecules characterized by the coexistence of ferroelectric and superfluid orders. Lastly, we propose an experiment to detect ferroelectric correlations through the observation of coherent dipole radiation pulses during time of flight.

Heteropairing and component-dependent pseudogap phenomena in an ultracold Fermi gas with different species with different masses

“…Although no one has succeeded in this attempt, various possibilities have been so far explored, such as a p-wave superfluid [5][6][7][8][9][10][11][12][13], the Berezinskii-Kosterlitz-Thouless state [14][15][16][17][18], a superfluid state with hetero-Cooper-pairs , the Sarma phase [39,40,43,44], a Fermi superfluid with a spin-orbit interaction [45][46][47][48], and a dipolar Fermi superfluid [49,50]. Once one of them is realized, one could clarify its superfluid properties, maximally using the high tunability of Fermi gases [51] and various experimental techniques [52][53][54][55][56][57][58].…”

Anisotropic superfluidity of two-dimensional excitons in a periodic potential

“…Anisotropy there is caused by a condensate of atomic pairs with nonzero spin formed at low temperatures. Anisotropic superfluidity has been observed in atomic systems in optical lattices 96,97 due to asymmetry x ↔ y of the lattice potential. In this case anisotropy can be controlled : the reciprocal lattice vector sets the selected direction and the amplitude of the potential governs the strength of anisotropic effects.…”

“…In the 3D case this leads to an elliptical form of vortex loops 97 . Vortex cores become elliptical as well 98 .…”

Hydrodynamic Expansion of a Strongly Interacting Fermi-Fermi Mixture

“…The recent experimental efforts to create ultracold mixtures of two different fermionic species [10][11][12][13][14][15][16][17] have brought the field close to a new research frontier with intriguing new possibilities, e.g. related to novel types of superfluids and quantum phases [18,19] and to new few-body states [20,21].…”