Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Fluctuating diamagnetism in underdoped high temperature superconductors   The fluctuation induced diamagnetism of underdoped high temperature
superconductors is studied in the framework of the Lawrence-Doniach model. By
taking into account the fluctuations of the phase of the order parameter only,
the latter reduces to a layered XY-model describing a liquid of vortices which
can be either thermally excited or induced by the external magnetic field. The
diamagnetic response is given by a current-current correlation function which
is evaluated using the Coulomb gas analogy. Our results are then applied to
recent measurements of fluctuation diamagnetism in underdoped YBCO. They allow
to understand both the observed anomalous temperature dependence of the
zero-field susceptibility and the two distinct regimes appearing in the
magnetic field dependence of the magnetization.

24
The categories of this paper are: dg-ga
10
The categories of this paper are: q-bio
21
The categories of this paper are: adap-org
31
The categories of this paper are: ao-sci
25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
5
The categories of this paper are: gr-qc
13
The categories of this paper are: quant-ph
27
The categories of this paper are: comp-gas
17
The categories of this paper are: q-fin
14
The categories of this paper are: math-ph
12
The categories of this paper are: nucl-th
33
The categories of this paper are: plasm-ph
19
The categories of this paper are: eess
22
The categories of this paper are: chao-dyn
6
The categories of this paper are: astro-ph