Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Finite-temperature topological invariant for interacting systems   We generalize the Ensemble Geometric Phase (EGP), recently introduced to
classify the topology of density matrices, to finite-temperature states of
interacting systems in one spatial dimension (1D). This includes cases where
the gapped ground state has a fractional filling and is degenerate. At zero
temperature the corresponding topological invariant agrees with the well-known
invariant of Niu, Thouless and Wu. We show that its value at finite
temperatures is identical to that of the ground state below some critical
temperature $T_c$ larger than the many-body gap. We illustrate our result with
numerical simulations of the 1D extended super-lattice Bose-Hubbard model at
quarter filling. Here a cyclic change of parameters in the ground state leads
to a topological charge pump with fractional winding $\nu=1/2$. The particle
transport is no longer quantized when the temperature becomes comparable to the
many-body gap, yet the winding of the generalized EGP is.

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The categories of this paper are: chem-ph
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The categories of this paper are: hep-ph
7
The categories of this paper are: hep-th
9
The categories of this paper are: nlin
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The categories of this paper are: comp-gas
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The categories of this paper are: q-alg
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The categories of this paper are: eess
6
The categories of this paper are: astro-ph
25
The categories of this paper are: patt-sol
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The categories of this paper are: adap-org
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The categories of this paper are: supr-con
8
The categories of this paper are: hep-ex
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The categories of this paper are: ao-sci
5
The categories of this paper are: gr-qc
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The categories of this paper are: hep-lat
2
The categories of this paper are: math