Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Elastic String in a Random Potential   We have studied numerically the dynamics of a directed elastic string in a
two-dimensional array of quenched random impurities. The string is driven by a
constant transverse force and thermal fluctuations are neglected. There is a
transition from pinned to unpinned behavior at a critical value $F_T$ of the
driving force. At the transition the average string velocity scales with the
driving force. The scaling is equally well described by a power law $v_d\sim
(F-F_T)^\zeta$, with $\zeta=0.24\pm0.1$, or by a logarithm,
$v_d\sim1/\ln(F-F_T)$. The divergence of the velocity-velocity correlation
length at threshold is characterized by an exponent $\nu=1.05\pm0.1$.

5
The categories of this paper are: gr-qc
3
The categories of this paper are: physics
35
The categories of this paper are: mtrl-th
17
The categories of this paper are: q-fin
20
The categories of this paper are: acc-phys
8
The categories of this paper are: hep-ex
36
The categories of this paper are: cmp-lg
30
The categories of this paper are: q-alg
32
The categories of this paper are: atom-ph
16
The categories of this paper are: stat
7
The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas
2
The categories of this paper are: math
37
The categories of this paper are: supr-con
28
The categories of this paper are: alg-geom
15
The categories of this paper are: nucl-ex