Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Classical Localization of an Unbound Particle in a Two-Dimensional
  Periodic Potential and Surface Diffusion   In periodic, two-dimensional potentials a classical particle might be
expected to escape from any finite region if it has enough energy to escape
from a single cell. However, for a class of sinusoidal potentials in which the
barriers between neighboring cells can be varied, numerical tridiagonalization
of Liouville's equation for the evolution of functions on phase space reveals a
transition from localized to delocalized motion at a total energy significantly
above that needed to escape from a single cell. It is argued that this purely
elastic phenomenon increases the effective barrier for diffusion of atoms on
crystalline surfaces and changes its temperature dependence at low temperatures
when inelastic events are rare.

22
The categories of this paper are: chao-dyn
7
The categories of this paper are: hep-th
14
The categories of this paper are: math-ph
35
The categories of this paper are: mtrl-th
12
The categories of this paper are: nucl-th
21
The categories of this paper are: adap-org
31
The categories of this paper are: ao-sci
5
The categories of this paper are: gr-qc
1
The categories of this paper are: cs
29
The categories of this paper are: funct-an
13
The categories of this paper are: quant-ph
0
The categories of this paper are: hep-ph
11
The categories of this paper are: hep-lat
36
The categories of this paper are: cmp-lg
15
The categories of this paper are: nucl-ex
9
The categories of this paper are: nlin