M.IskinandC.A.R.SdeMelo创新.PDFVIP

PHYSICAL REVIEW B 72, 224513 2005 Superfluidity of p -wave and s-wave atomic Fermi gases in optical lattices M. Iskin and C. A. R. Sá de Melo School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA Received 4 August 2005; revised manuscript received 27 October 2005; published 16 December 2005 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 analyze superfluid properties of p -wave and s-wave symmetries in the strictly weak coupling BCS regime where we discuss the order param- eter, chemical potential, critical temperature, atomic compressibility, and superfluid density as a function of filling factor for tetragonal and orthorhombic optical lattices. Second, we analyze superfluid properties of p -wave and s-wave superfluids in the evolution from the BCS to Bose-Einstein condensation regimes at low temperatures T 0, where we discuss the changes in the quasiparticle excitation spectrum, chemical poten- tial, atomic compressibility, Cooper pair size, and momentum distribution as a function of filling factor and interaction strength for tetragonal and orthorhombic optical lattices. DOI: 10.1103/PhysRevB.72.224513 PACS numbers: 74.25.Bt, 74.25.Dw, 03.75.Ss, 03.75.Hh I. INTRODUCTION with different mF , which can be made to correspond to pseu- dospin labels. Trapping