Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Reduction of topological $\mathbb{Z}$ classification in cold atomic
  systems   One of the most challenging problems in correlated topological systems is a
realization of the reduction of topological classification, but very few
experimental platforms have been proposed so far. We here demonstrate that
ultracold dipolar fermions (e.g., $^{167}$Er, $^{161}$Dy, and $^{53}$Cr) loaded
in an optical lattice of two-leg ladder geometry can be the first promising
testbed for the reduction $\mathbb{Z}\to\mathbb{Z}_4$, where solid evidence for
the reduction is available thanks to their high controllability. We further
give a detailed account of how to experimentally access this phenomenon; around
the edges, the destruction of one-particle gapless excitations can be observed
by the local radio frequency spectroscopy, while that of gapless spin
excitations can be observed by a time-dependent spin expectation value of a
superposed state of the ground state and the first excited state. We clarify
that even when the reduction occurs, a gapless edge mode is recovered around a
dislocation, which can be another piece of evidence for the reduction.

14
The categories of this paper are: math-ph
29
The categories of this paper are: funct-an
35
The categories of this paper are: mtrl-th
15
The categories of this paper are: nucl-ex
24
The categories of this paper are: dg-ga
7
The categories of this paper are: hep-th
22
The categories of this paper are: chao-dyn
8
The categories of this paper are: hep-ex
27
The categories of this paper are: comp-gas
9
The categories of this paper are: nlin
13
The categories of this paper are: quant-ph
36
The categories of this paper are: cmp-lg
28
The categories of this paper are: alg-geom
10
The categories of this paper are: q-bio
33
The categories of this paper are: plasm-ph
25
The categories of this paper are: patt-sol