Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Manipulation of collective spin correlations in semiconductors with
  polarization squeezed vacuum   We calculate the transfer rate of correlations from polarization entangled
photons to the collective spin of a many-electron state in a two-band system.
It is shown that when a semiconductor absorbs pairs of photons from a two-mode
squeezed vacuum, certain fourth order electron-photon processes correlate the
spins of the excited electron pairs of different quasi-momenta. Different
distributions of the quantum Stokes vector of the light lead to either
enhancement or reduction of the collective spin correlations, depending on the
symmetry of the distribution. We find that as the squeezing of the light
becomes non-classical, the spin correlations exhibit a crossover from being
positive with a $\sim N^2$ ($N$ is average photon number) scaling, to being
negative with $\sim N$ scaling, even when $N$ is not small. Negative spin
correlations mean a preponderance of spin singlets in the optically generated
state. We discuss the possibility to measure the collective spin correlations
in a combined measurement of the Faraday rotation fluctuation spectrum and
excitation density in a steady-state configuration.

17
The categories of this paper are: q-fin
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
16
The categories of this paper are: stat
9
The categories of this paper are: nlin
14
The categories of this paper are: math-ph
0
The categories of this paper are: hep-ph
18
The categories of this paper are: econ
1
The categories of this paper are: cs
6
The categories of this paper are: astro-ph
37
The categories of this paper are: supr-con
22
The categories of this paper are: chao-dyn
3
The categories of this paper are: physics
24
The categories of this paper are: dg-ga
12
The categories of this paper are: nucl-th