Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Vanishing environment-induced decoherence   For a central system uniformly coupled to a XY spin-1/2 bath in a transverse
field, we explicitly calculate the Loschmidt echo(LE) to characterize
decoherence quantitatively. We find that the anisotropy parameter $\gamma $
affects decoherence of the central system sensitively when $\gamma \in [0,1]$%
, in particular, the LE becomes unit without varying with time when $\gamma =0
$, implying that environment-induced decoherence vanishes . Some other cases in
which the LE is unit are discussed also.

16
The categories of this paper are: stat
24
The categories of this paper are: dg-ga
7
The categories of this paper are: hep-th
34
The categories of this paper are: chem-ph
1
The categories of this paper are: cs
36
The categories of this paper are: cmp-lg
2
The categories of this paper are: math
9
The categories of this paper are: nlin
6
The categories of this paper are: astro-ph
18
The categories of this paper are: econ
5
The categories of this paper are: gr-qc
15
The categories of this paper are: nucl-ex
23
The categories of this paper are: solv-int
8
The categories of this paper are: hep-ex
35
The categories of this paper are: mtrl-th
10
The categories of this paper are: q-bio