Optical spin transport theory of spin-1/2 topological Fermi superfluids

Abstract

We theoretically investigate optical (frequency-dependent) bulk spin transport properties in a spin-1/2 topological Fermi superfluid. We specifically consider a one-dimensional system with an interspin {\it p}-wave interaction, which can be realized in ultracold atom experiments. Developing the BCS-Leggett theory to describe the Bardeen-Cooper-Schrieffer (BCS) to Bose-Einstein condensate (BEC) evolution and the ${\mathbb{Z}}_2$ topological phase transition in this system, we show how the spin transport reflects these many-body aspects. We find that the optical spin conductivity, which is a small AC response of a spin current, shows the spin gapped spectrum in the wide parameter region and the gap closes at ${\mathbb{Z}}_2$ topological phase transition point. Moreover, the validity of the low-energy effective model of the Majorana zero mode is discussed along the BCS-BEC evolution in connection with the scale invariance at {\it p}-wave unitarity.

arXiv comment10 pages, 5 figures, accepted version for publication in Phys. Rev. B

References in corpus (65)

• Topological insulators and superconductors
• $Z_2$ Topological Order and the Quantum Spin Hall Effect
• Classification of topological insulators and superconductors in three spatial dimensions
• Search for Majorana fermions in superconductors
• Topological superconductors: a review
• Color superconductivity in dense quark matter
• Non-Abelian Topological Order in S-Wave Superfluids of Ultracold Fermionic Atoms
• Pairing in nuclear systems: from neutron stars to finite nuclei
• Universal Thermodynamics of Degenerate Quantum Gases in the Unitarity Limit
• Tools for quantum simulation with ultracold atoms in optical lattices
• Dynamic exchange coupling in magnetic bilayers
• Resonantly-paired fermionic superfluids
• Majorana Fermions and Topology in Superconductors
• Tuning p-wave interactions in an ultracold Fermi gas of atoms
• BCS-BEC Crossover and the Unitary Fermi Gas
• The BCS-BEC crossover: From ultra-cold Fermi gases to nuclear systems
• Quantum phase transitions across p-wave Feshbach resonance
• P-wave Feshbach resonances of ultra-cold ${}^6$Li
• Fermion-Boson Duality of One-dimensional Quantum Particles with Generalized Contact Interaction
• Mechanical generation of spin current by spin-rotation coupling
• Tuning the interactions of spin-polarized fermions using quasi-one-dimensional confinement
• Symmetry Protected Topological Superfluids and Superconductors --- From the Basics to ${}^3$He ---
• Experimental observation of a large ac-spin Hall effect
• Detection of the microwave spin pumping using the inverse spin Hall effect
• Collisional Properties of p-Wave Feshbach Molecules
• Fermion Superfluids of Non-Zero Orbital Angular Momentum near Resonance
• BCS-BEC crossover in a gas of Fermi atoms with a p-wave Feshbach resonance
• Quantized conductance through a spin-selective atomic point contact
• Causality and the effective range expansion
• Theory of spinor Fermi and Bose gases in tight atom waveguides
• Role of the Majorana Fermion and the Edge Mode in Chiral Superfluidity near a p-Wave Feshbach Resonance
• Quantum mechanical limitations to spin diffusion in the unitary Fermi gas
• Direct detection of pure spin-current by x-ray pump-probe measurements
• Phase-sensitive detection of spin pumping via the ac inverse spin Hall effect
• Resonant Scattering of Ultracold Atoms in Low Dimensions
• Conductivity spectrum of ultracold atoms in an optical lattice
• Topological superfluid in a Fermi-Bose mixture with a high critical temperature
• Tunneling transport of unitary fermions across the superfluid transition
• Universal One-dimensional Atomic Gases Near Odd-wave Resonance
• Causality and universality in low-energy quantum scattering
• Bosonization, Pairing, and Superconductivity of the Fermionic Tonks-Girardeau Gas
• Bose-Fermi dualities for arbitrary one-dimensional quantum systems in the universal low energy regime
• Scaling Law for Three-body Collisions in Identical Fermions with $p$-wave Interactions
• Two-body relaxation in a Fermi gas at a p-wave Feshbach resonance
• Collisional loss of one-dimensional fermions near a $p$-wave Feshbach resonance
• Universal Spin Transport and Quantum Bounds for Unitary Fermions
• Exponentially decaying correlations in a gas of strongly interacting spin-polarized 1D fermions with zero-range interactions
• Field-theoretical aspects of one-dimensional Bose and Fermi gases with contact interactions
• Unitarity-limited behavior of three-body collisions in a p-wave interacting Fermi gas
• Comparative study of one-dimensional Bose and Fermi gases with contact interactions from the viewpoint of universal relations for correlation functions
• Universal duality transformations in interacting one-dimensional quantum systems
• Stretching p-wave molecules by transverse confinements
• Two-body relaxation of spin-polarized fermions in reduced dimensionalities near a p-wave Feshbach resonance
• Quantitative analysis of $p$-wave three-body losses via cascade process
• Mesoscopic spin transport between strongly interacting Fermi gases
• Spin-exchange-induced exotic superfluids in a Bose-Fermi spinor mixture
• Probing the optical conductivity of trapped charge-neutral quantum gases
• Many-body stabilization of a resonant p-wave Fermi gas in one dimension
• Unitary $p$-wave Fermi gas in one dimension
• Simulating quantum transport with ultracold atoms and interaction effects
• Shear viscosity and spin sum rules in strongly interacting Fermi gases
• Ground-state properties of dilute spinless fermions in fractional dimensions
• Highly polarized one-dimensional Fermi gases near a narrow $p-$wave resonance
• Bright and dark solitary waves in a one-dimensional spin-polarized gas of fermionic atoms with p-wave interactions in a hard-wall trap
• Non-Abelian Majorana fermions in topological $s$-wave Fermi superfluids

Cited by in corpus (6)

• Intersections of ultracold atomic polarons and nuclear clusters: How is a chart of nuclides modified in dilute neutron matter?
• Non-Hermitian topological Fermi superfluid near the $p$-wave unitary limit
• Stability against three-body clustering in one-dimensional spinless p-wave fermions
• Optical spin conductivity in ultracold quantum gases
• Spin conductivity spectrum and spin superfluidity in a binary Bose mixture
• Non-Hermitian $p$-wave superfluid and effects of the inelastic three-body loss in a one-dimensional spin-polarized Fermi gas