Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Two-Mode Squeezed States and Their Superposition in the Motion of Two
  Trapped Ions   We propose a method to create two-mode squeezed states and their
superposition in the center-of-mass mode and breathing mode of two-trapped
ions. Each ion is illuminated simultaneously by two standing waves. One of the
fields is tuned to excite resonantly and simultaneously both upper sidebands of
the two normal modes, while the other field tuned to the corresponding lower
sidebands.

29
The categories of this paper are: funct-an
37
The categories of this paper are: supr-con
19
The categories of this paper are: eess
14
The categories of this paper are: math-ph
6
The categories of this paper are: astro-ph
3
The categories of this paper are: physics
23
The categories of this paper are: solv-int
35
The categories of this paper are: mtrl-th
33
The categories of this paper are: plasm-ph
7
The categories of this paper are: hep-th
9
The categories of this paper are: nlin
17
The categories of this paper are: q-fin
26
The categories of this paper are: bayes-an
15
The categories of this paper are: nucl-ex
4
The categories of this paper are: cond-mat
32
The categories of this paper are: atom-ph