Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Compressibility in Strongly Correlated Superconductors and
  Superfluids: From BCS to BEC   We present a theoretical study of the compressibility, $\kappa$, in a Fermi
gas with attractive contact interactions, providing predictions for the
strongly-attractive regime and the superfluid phase. Our work emphasizes the
compressibility sum rule and gauge invariance as constraints on $\kappa$ and we
show how within a particular $t$-matrix approach, these can be satisfied in the
normal phase when no approximations are made. For tractability, approximations
must be introduced, and it is believed that thermodynamical approaches to
$\kappa$ are more reliable, than correlation function based schemes.
Contrasting with other studies in the literature, we present thermodynamic
calculations of $\kappa$; these yield semi-quantitative agreement with
experiment and provide physical insight into similar results obtained via
quantum Monte Carlo simulations.

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The categories of this paper are: q-fin
30
The categories of this paper are: q-alg
2
The categories of this paper are: math
18
The categories of this paper are: econ
32
The categories of this paper are: atom-ph
15
The categories of this paper are: nucl-ex
35
The categories of this paper are: mtrl-th
6
The categories of this paper are: astro-ph
22
The categories of this paper are: chao-dyn
25
The categories of this paper are: patt-sol
26
The categories of this paper are: bayes-an
34
The categories of this paper are: chem-ph
3
The categories of this paper are: physics
14
The categories of this paper are: math-ph
5
The categories of this paper are: gr-qc
13
The categories of this paper are: quant-ph