Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Critical microwave-conductivity fluctuations across the phase diagram of
  superconducting La$_{2-x}$Sr$_x$CuO$_4$ thin films   We report a systematic study of the dynamic microwave conductivity near $T_c$
for La$_{2-x}$Sr$_x$CuO$_4$ (LSCO) thin films with $x$=0.07 to 0.16. The strong
frequency dependence of the phase stiffness together with scaling analysis of
the ac fluctuating conductivity of superconductivity provide direct evidence
for the 2D-XY behavior of nearly decoupled CuO$_2$ planes in underdoped LSCO
($x$=0.07 and 0.12). On the other hand, the critical exponents for slightly
overdoped LSCO ($x$=0.16) were found to agree with those for the relaxational
3D-XY model, indicating that the universality class in LSCO is changed by hole
doping. The implication of these results for the phase diagram of high-$T_c$
cuprates is discussed.

20
The categories of this paper are: acc-phys
19
The categories of this paper are: eess
25
The categories of this paper are: patt-sol
30
The categories of this paper are: q-alg
12
The categories of this paper are: nucl-th
37
The categories of this paper are: supr-con
21
The categories of this paper are: adap-org
32
The categories of this paper are: atom-ph
16
The categories of this paper are: stat
9
The categories of this paper are: nlin
35
The categories of this paper are: mtrl-th
28
The categories of this paper are: alg-geom
2
The categories of this paper are: math
22
The categories of this paper are: chao-dyn
8
The categories of this paper are: hep-ex
0
The categories of this paper are: hep-ph