Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Superfluidity, Sound Velocity and Quasi Condensation in the 2D BCS-BEC
  Crossover   We study finite-temperature properties of a two-dimensional superfluid made
of ultracold alkali-metal atoms in the BCS-BEC crossover. We investigate the
region below the critical temperature $T_{BKT}$ of the
Berezinskii-Kosterlitz-Thouless phase transition, where there is
quasi-condensation, by analyzing the effects of phase and amplitude
fluctuations of the order parameter. In particular, we calculate the superfluid
fraction, the sound velocity and the quasi-condensate fraction as a function of
the temperature and of the binding energy of fermionic pairs.

29
The categories of this paper are: funct-an
0
The categories of this paper are: hep-ph
1
The categories of this paper are: cs
17
The categories of this paper are: q-fin
5
The categories of this paper are: gr-qc
16
The categories of this paper are: stat
13
The categories of this paper are: quant-ph
26
The categories of this paper are: bayes-an
37
The categories of this paper are: supr-con
24
The categories of this paper are: dg-ga
2
The categories of this paper are: math
21
The categories of this paper are: adap-org
33
The categories of this paper are: plasm-ph
25
The categories of this paper are: patt-sol
11
The categories of this paper are: hep-lat
23
The categories of this paper are: solv-int