title: Fermion pairing across a dipolar interaction induced resonance.
abstract: It is known from the solution of the two-body problem that an anisotropic dipolar interaction can give rise to s-wave scattering resonances, which are named dipolar interaction induced resonances (DIIR). In this Letter, we study the zero-temperature many-body physics of a two-component Fermi gas across a DIIR. In the low-density regime, it is very striking that the resulting pairing order parameter is a nearly isotropic singlet pairing and the physics can be well described by an s-wave resonant interaction potential with finite range conditions, despite the anisotropic nature of the dipolar interaction. The pairing energy is as strong as a unitary Fermi gas near a magnetic Feshbach resonance. In the high-density regime, the anisotropic effect plays an important role. We find phase transitions from singlet pairing to a state with mixed singlet and triplet pairing and then from mixed pairing to pure triplet pairing. The state with mixed pairing spontaneously breaks the time-reversal symmetry.
authors.affiliation: Institute for Advanced Study, Tsinghua University, Beijing 100084, China.
authors.forename: Ran
authors.initials: R
authors.lastname: Qi
authors.affiliation: Institute for Advanced Study, Tsinghua University, Beijing 100084, China.
authors.forename: Zhe-Yu
authors.initials: ZY
authors.lastname: Shi
authors.affiliation: Institute for Advanced Study, Tsinghua University, Beijing 100084, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhai