Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Anomalous critical fields in quantum critical superconductors   Fluctuations around an antiferromagnetic quantum critical point (QCP) are
believed to lead to unconventional superconductivity and in some cases to
high-temperature superconductivity. However, the exact mechanism by which this
occurs remains poorly understood. The iron-pnictide superconductor
BaFe$_2$(As$_{1-x}$P$_x$)$_2$ is perhaps the clearest example to date of a high
temperature quantum critical superconductor, and so it is a particularly
suitable system in which to study how the quantum critical fluctuations affect
the superconducting state. Here we show that the proximity of the QCP yields
unexpected anomalies in the superconducting critical fields. We find that both
the lower and upper critical fields strongly violate the expectations from the
conventional theory taking into account the observed mass enhancement near the
QCP. These anomalous behaviours of the critical fields imply that the energy of
superconducting vortices is enhanced, possibly due to a microscopic mixing of
antiferromagnetism and superconductivity, suggesting that a highly unusual
vortex state is realised in quantum critical superconductors.

30
The categories of this paper are: q-alg
7
The categories of this paper are: hep-th
29
The categories of this paper are: funct-an
23
The categories of this paper are: solv-int
6
The categories of this paper are: astro-ph
35
The categories of this paper are: mtrl-th
2
The categories of this paper are: math
32
The categories of this paper are: atom-ph
28
The categories of this paper are: alg-geom
26
The categories of this paper are: bayes-an
22
The categories of this paper are: chao-dyn
14
The categories of this paper are: math-ph
0
The categories of this paper are: hep-ph
16
The categories of this paper are: stat
10
The categories of this paper are: q-bio
12
The categories of this paper are: nucl-th