Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Pattern Switching and Polarizability for Colloids in Optical Trap Arrays   We show that colloidal molecular crystal states interacting with a periodic
substrate, such as an optical trap array, and a rotating external field can
undergo a rapid pattern switching in which the orientation of the crystal
changes. In some cases, a martensitic-like symmetry switching occurs. It is
also possible to create a polarized state where the colloids in each substrate
minima develop a director field which smoothly rotates with the external drive,
similar to liquid crystal behavior. These results open the possibility for
creating novel types of devices using photonic band gap materials, and should
be generalizable to a variety of other condensed matter systems with multiple
particle trapping.

19
The categories of this paper are: eess
37
The categories of this paper are: supr-con
18
The categories of this paper are: econ
8
The categories of this paper are: hep-ex
3
The categories of this paper are: physics
11
The categories of this paper are: hep-lat
31
The categories of this paper are: ao-sci
30
The categories of this paper are: q-alg
6
The categories of this paper are: astro-ph
5
The categories of this paper are: gr-qc
1
The categories of this paper are: cs
10
The categories of this paper are: q-bio
32
The categories of this paper are: atom-ph
27
The categories of this paper are: comp-gas
9
The categories of this paper are: nlin
36
The categories of this paper are: cmp-lg