Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Decoherence-free subspaces for a quantum register interacting with a
  spin environment   We study a model of a quantum spin register interacting with an environment
of spin particles in quantum-measurement limit. In the limit of collective
decoherence we obtain the form of state vectors that constitute
high-dimensional decoherence-free subspaces (DFS). In a more general setting we
present sufficient and necessary conditions for existence of low-dimensional
DFSs that can be used to construct subspaces of higher dimension.

22
The categories of this paper are: chao-dyn
18
The categories of this paper are: econ
32
The categories of this paper are: atom-ph
26
The categories of this paper are: bayes-an
37
The categories of this paper are: supr-con
34
The categories of this paper are: chem-ph
29
The categories of this paper are: funct-an
3
The categories of this paper are: physics
9
The categories of this paper are: nlin
19
The categories of this paper are: eess
4
The categories of this paper are: cond-mat
1
The categories of this paper are: cs
23
The categories of this paper are: solv-int
36
The categories of this paper are: cmp-lg
21
The categories of this paper are: adap-org
16
The categories of this paper are: stat