Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Classical threshold behaviour in a 1+1-dimensional model for double
  ionization in strong fields   Building on insights about the classical pathways to double ionization in
strong laser fields we here propose a 1+1-dimensional model that captures
essentials of the 3-d potential landscape and allows efficient studies of the
process in reduced dimensions. The reduction to one degree of freedom for each
electron is obtained by confining their motion to lines at an angle of pi/6
with respect to the field axis; the justification for this choice is that upon
variation of the electric field the Stark saddles move along the same lines. In
this way we obtain a low-dimensional representation in which symmetric electron
escape is possible. As a demonstration of the advantages of this model we
confirm numerically the equivalent of the Wannier threshold behaviour for
constant electric field and identify several classes of trajectories that can
contribute to the ionization process.

36
The categories of this paper are: cmp-lg
5
The categories of this paper are: gr-qc
11
The categories of this paper are: hep-lat
27
The categories of this paper are: comp-gas
6
The categories of this paper are: astro-ph
4
The categories of this paper are: cond-mat
13
The categories of this paper are: quant-ph
25
The categories of this paper are: patt-sol
22
The categories of this paper are: chao-dyn
23
The categories of this paper are: solv-int
16
The categories of this paper are: stat
33
The categories of this paper are: plasm-ph
18
The categories of this paper are: econ
2
The categories of this paper are: math
17
The categories of this paper are: q-fin
20
The categories of this paper are: acc-phys