Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Entanglement of a two-atom system driven by the quantum vacuum in
  arbitrary cavity size   We study the dynamical entanglement of two identical atoms interacting with a
quantum field. As a simplified model for this physical system we consider two
harmonic oscillators linearly coupled to a massless scalar field in the dressed
coordinates and states approach and enclose the whole system inside a spherical
cavity of radius R. Through a quantity called concurrence, the entanglement
evolution for the two-atom system will be discussed, for a range of initial
states composed of a superposition of atomic states. Our results reveals how
the concurrence of the two atoms behaves through the time evolution, for
arbitrary cavity size and for arbitrary coupling constant, weak, intermediate
or strong. All our computations are exact and only the final step is numerical.
These numerical solutions give us fascinating results for the concurrence, such
as quasi-random fluctuations, with a resemblance of periodicity. Another
interesting result we found is when the system is initially maximally entangled
(disentangled), after the time t = 2R, the system becomes again strongly
entangled (disentangled) particularly during the first oscillations, later this
phenomenon could be wrecked depending on the initial condition. We also show
the concurrence after a too long time elapsed with a good precision.

12
The categories of this paper are: nucl-th
20
The categories of this paper are: acc-phys
15
The categories of this paper are: nucl-ex
31
The categories of this paper are: ao-sci
4
The categories of this paper are: cond-mat
33
The categories of this paper are: plasm-ph
1
The categories of this paper are: cs
19
The categories of this paper are: eess
23
The categories of this paper are: solv-int
10
The categories of this paper are: q-bio
18
The categories of this paper are: econ
11
The categories of this paper are: hep-lat
3
The categories of this paper are: physics
34
The categories of this paper are: chem-ph
9
The categories of this paper are: nlin
21
The categories of this paper are: adap-org