Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Optical spin transport theory of spin-1/2 topological Fermi superfluids   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.

26
The categories of this paper are: bayes-an
20
The categories of this paper are: acc-phys
16
The categories of this paper are: stat
2
The categories of this paper are: math
11
The categories of this paper are: hep-lat
21
The categories of this paper are: adap-org
23
The categories of this paper are: solv-int
31
The categories of this paper are: ao-sci
27
The categories of this paper are: comp-gas
37
The categories of this paper are: supr-con
24
The categories of this paper are: dg-ga
10
The categories of this paper are: q-bio
36
The categories of this paper are: cmp-lg
9
The categories of this paper are: nlin
33
The categories of this paper are: plasm-ph
30
The categories of this paper are: q-alg