Superfluidity ofp-wave ands-wave atomic Fermi gases in optical lattices

Abstract

We consider p-wave pairing of single hyperfine state and s-wave pairing of two hyperfine states ultracold atomic gases trapped in quasi-two-dimensional optical lattices. First, we analyse superfluid properties of p-wave and s-wave symmetries in the strictly weak coupling BCS regime where we discuss the order parameter, chemical potential, critical temperature, atomic compressibility and superfluid density as a function of filling factor for tetragonal and orthorhombic optical lattices. Second, we analyse superfluid properties of p-wave and s-wave superfluids in the evolution from BCS to BEC regime at low temperatures (T ≈ 0), where we discuss the changes in the quasi-particle excitation spectrum, chemical potential, atomic compressibility, Cooper pair size and momentum distribution as a function of filling factor and interaction strength for tetragonal and orthorhombic optical lattices.

Excitation properties and effects of mass imbalance in the BCS-BEC crossover regime of an ultracold Fermi gas

“…Since the achievement of the superfluid phase transition in 40 K [1] and 6 Li [2][3][4] Fermi gases, various possibilities beyond this simplest s-wave pairing state have been discussed in this field, such as a p-wave superfluid [5][6][7][8][9][10][11][12][13], the Sarma phase [14][15][16][17], a dipolar Fermi condensate [18][19][20][21][22], and a mass-imbalanced Fermi superfluid [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41]. Although none of these states has been observed yet, the high tunability of cold Fermi gases makes us expect that some of them may be realized in the near future.…”

Radio-frequency spectroscopy ofLi6p-wave molecules: Towards photoemission spectroscopy of aMaier1, Marzok2, Zimmermann3 et al. 2010Phys. Rev. A

“…Depending on the interaction strength, the superfluid phase has been found to be either stable or unstable against decay into fermionic trimers [11]. In optical lattices, even more exotic superfluid phases are expected [12]. By studying higher partial-wave superfluidity with ultracold atoms, new insight into the pairing physics of other condensed matter systems may be gained.…”

Superfluidity of identical fermions in an optical lattice: Atoms and polar molecules

“…At the same time, the tunneling becomes weaker. The combined effect of these two factors is a strong increase in the critical temperature [3][4][5]. This has been observed in the MIT experiment [6].…”

“…The creation of p x + ip y atomic or molecular topological superfluids in 2D optical lattices can be a promising path for quantum information processing [1,2], since addressing qubits in the lattice should be much easier than in the gas phase. For short-range interacting atomic fermions, the effect of the lattice potential on the formation of a superfluid phase of atomic fermions has been actively discussed [3][4][5][6][7][8][9][10]. In particular, for the s-wave pairing of spin-1/2 fermions an increase in the depth of the optical potential results in a stronger atom localization and hence in increasing the on-site interaction.…”