Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Phase-dependent decoherence of optical transitions in Pr3+:LaF3 in the
  presence of a driving field   The decoherence times of orthogonally phased components of the optical
transition dipole moment in a two-level system have been observed to differ by
an order of magnitude. This phase anisotropy is observed in coherent transient
experiments where an optical driving field is present during extended periods
of decoherence. The decoherence time of the component of the dipole moment in
phase with the driving field is extended compared to T_2, obtained from
two-pulse photon echoes, in analogy with the spin locking technique of NMR.

32
The categories of this paper are: atom-ph
15
The categories of this paper are: nucl-ex
36
The categories of this paper are: cmp-lg
37
The categories of this paper are: supr-con
26
The categories of this paper are: bayes-an
6
The categories of this paper are: astro-ph
31
The categories of this paper are: ao-sci
0
The categories of this paper are: hep-ph
20
The categories of this paper are: acc-phys
18
The categories of this paper are: econ
2
The categories of this paper are: math
1
The categories of this paper are: cs
5
The categories of this paper are: gr-qc
12
The categories of this paper are: nucl-th
30
The categories of this paper are: q-alg
25
The categories of this paper are: patt-sol