arXiv:cond-mat/0503622 · Physical Review A

Anomalous quantum mass flow of atoms in p -wave resonance

W. Vincent Liu

Published Nov 14, 2005• 5 citations

Abstract

I analyze an atomic Fermi gas with a planar $p$-wave interaction, motivated by the experimentally observed anisotropy in $p$-wave Feshbach resonances. An axial superfluid state is verified. A domain wall object is discovered to be a new topological defect of this superfluid and an explicit solution has been found. Gapless quasiparticles appear as bound states on the wall, dispersing in the continuum of reduced dimensions. They are chiral, deeply related to fermion zero modes in quantum chromodynamics. The chirality of the superfluid is manifested by a persistent anomalous mass current of atoms in the ground state. This quantum phenomenon is a prediction for future experiments.

DOI: 10.1103/physreva.72.053613

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arXiv:cond-mat/0503622 · Physical Review A

Anomalous quantum mass flow of atoms in p -wave resonance

W. Vincent Liu

Published Nov 14, 2005• 5 citations

arXiv HTML PDF

Abstract

I analyze an atomic Fermi gas with a planar

p

-wave interaction, motivated by the experimentally observed anisotropy in

p

-wave Feshbach resonances. An axial superfluid state is verified. A domain wall object is discovered to be a new topological defect of this superfluid and an explicit solution has been found. Gapless quasiparticles appear as bound states on the wall, dispersing in the continuum of reduced dimensions. They are chiral, deeply related to fermion zero modes in quantum chromodynamics. The chirality of the superfluid is manifested by a persistent anomalous mass current of atoms in the ground state. This quantum phenomenon is a prediction for future experiments.

DOI: 10.1103/physreva.72.053613

Related papers

p -wave superfluid and phase separation in atomic Bose-Fermi mixtures

Kazunori Suzuki, Takahiko Miyakawa, T. Suzuki

We consider a system of repulsively interacting Bose-Fermi mixtures of spin-polarized uniform atomic gases at zero temperature. We examine possible realization of $p$ -wave superfluidity of fermions due to an effective attractive interaction via density fluctuations of Bose-Einstein condensate within mean-field approximation. We find the ground state of the system by direct energy comparison of the $p$ -wave superfluid state in a single uniform mixed phase and normal Fermi gas state in a phase-separated phase, and suggest an occurrence of the $p$ -wave superfluidity for a strong boson-fermion interaction regime. We study some signatures of the $p$ -wave superfluid, such as anisotropic energy gap and quasiparticle energy in the axial state, that have not been observed in spin-unpolarized superfluid of atomic fermions. We also show that a Cooper pair is a tightly bound state, such as a diatomic molecule in the strong boson-fermion coupling regime, and suggest an observable indication of the $p$ -wave superfluid in the real experiment.We consider a system of repulsively interacting Bose-Fermi mixtures of spin-polarized uniform atomic gases at zero temperature. We examine possible realization of $p$-wave superfluidity of fermions due to an effective attractive interaction via density fluctuations of Bose-Einstein condensate within mean-field approximation. We find the ground state of the system by direct energy comparison of the $p$-wave superfluid state in a single uniform mixed phase and normal Fermi gas state in a phase-separated phase, and suggest an occurrence of the $p$-wave superfluidity for a strong boson-fermion interaction regime. We study some signatures of the $p$-wave superfluid, such as anisotropic energy gap and quasiparticle energy in the axial state, that have not been observed in spin-unpolarized superfluid of atomic fermions. We also show that a Cooper pair is a tightly bound state, such as a diatomic molecule in the strong boson-fermion coupling regime, and suggest an observable indication of the $p$-wave superfluid in the real experiment.

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arXiv:1302.1481Physical Review AMay 16, 20138 citations

I analyze an atomic Fermi gas with a planar

p

-wave interaction, motivated by the experimentally observed anisotropy in

p

We consider a system of repulsively interacting Bose-Fermi mixtures of spin-polarized uniform atomic gases at zero temperature. We examine possible realization of

p

-wave superfluidity of fermions due to an effective attractive interaction via density fluctuations of Bose-Einstein condensate within mean-field approximation. We find the ground state of the system by direct energy comparison of the

p

-wave superfluid state in a single uniform mixed phase and normal Fermi gas state in a phase-separated phase, and suggest an occurrence of the

p

-wave superfluidity for a strong boson-fermion interaction regime. We study some signatures of the

p

-wave superfluid, such as anisotropic energy gap and quasiparticle energy in the axial state, that have not been observed in spin-unpolarized superfluid of atomic fermions. We also show that a Cooper pair is a tightly bound state, such as a diatomic molecule in the strong boson-fermion coupling regime, and suggest an observable indication of the

p

-wave superfluid in the real experiment.

We discuss the emergence of

p

-wave superfluidity of identical atomic fermions in a two-dimensional optical lattice. The optical lattice potential manifests itself in an interplay between an increase in the density of states on the Fermi surface and the modification of the fermion-fermion interaction (scattering) amplitude. The density of states is enhanced due to an increase of the effective mass of atoms. In deep lattices the scattering amplitude is strongly reduced compared to free space due to a small overlap of wave functions of fermions sitting in the neighboring lattice sites, which suppresses the

p

-wave superfluidity. However, for moderate lattice depths the enhancement of the density of states can compensate the decrease of the scattering amplitude. Moreover, the lattice setup significantly reduces inelastic collisional losses, which allows one to get closer to a

p

-wave Feshbach resonance. This opens possibilities to obtain the topological

{p}_{x}+i{p}_{y}

superfluid phase, especially in the recently proposed subwavelength lattices. We demonstrate this for the two-dimensional version of the Kronig-Penney model allowing a transparent physical analysis.

We demonstrate that an exotically chiral

f

-wave topological superfluid can be induced in cold-fermionic-atom triangular optical lattices through a laser-field-generated effective non-Abelian gauge field, controllable Zeeman fields, and

s

-wave Feshbach resonance. We find that the chiral

f

-wave topological superfluid is characterized by three gapless Majorana edge states located on the boundary of the system. More interestingly, these Majorana edge states degenerate into one Majorana fermion bound to each vortex in the superfluid. Our proposal enlarges the topological superfluid family and specifies a unique experimentally controllable system to study Majorana fermion physics.