Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Simple models exhibiting spontaneous symmetry breakdown in classical and
  non-relativistic quantum mechanics   First, the properties of a classical model of spontaneous symmetry breakdown
are analyzed. Then, the pros and cons of some pedagogical non-relativistic
quantum-mechanical models, also used to illustrate spontaneous symmetry
breakdown, are discussed. Finally, a simple quantum-mechanical toy model (a
spinor on the line, with a spin-dependent interaction) is presented, that
exhibits the spontaneous breaking of an internal symmetry.

25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
33
The categories of this paper are: plasm-ph
19
The categories of this paper are: eess
16
The categories of this paper are: stat
35
The categories of this paper are: mtrl-th
21
The categories of this paper are: adap-org
11
The categories of this paper are: hep-lat
15
The categories of this paper are: nucl-ex
4
The categories of this paper are: cond-mat
10
The categories of this paper are: q-bio
1
The categories of this paper are: cs
24
The categories of this paper are: dg-ga
3
The categories of this paper are: physics
20
The categories of this paper are: acc-phys
5
The categories of this paper are: gr-qc