Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Comparison of different concurrences characterizing photon-pairs
  generated in the biexciton cascade in quantum dots coupled to microcavities   We compare three different notions of concurrence to measure the polarization
entanglement of two-photon states generated by the biexciton cascade in a
quantum dot embedded in a microcavity. We focus on the often-discussed
situation of a dot with finite biexciton binding energy in a cavity tuned to
the two-photon resonance. Apart from the time-dependent concurrence, which can
be assigned to the two-photon density matrix at any point in time, we study
single- and double-time integrated concurrences commonly used in the literature
that are based on different quantum state reconstruction schemes. We argue that
the single-time integrated concurrence can be thought of as the concurrence of
photons simultaneously emitted from the cavity without resolving the common
emission time, while the more widely studied double-time integrated concurrence
refers to photons that are neither filtered with respect to the emission time
of the first photon nor with respect to the delay time between the two emitted
photons. Analytic and numerical calculations reveal that the single-time
integrated concurrence indeed agrees well with the typical value of the
time-dependent concurrence at long times, even in the presence of phonons.
Thus, the more easily measurable single-time integrated concurrence gives
access to the physical information represented by the time-dependent
concurrence. However, the double-time integrated concurrence shows a different
behavior with respect to changes in the exciton fine structure splitting and
even displays a completely different trend when the ratio between the cavity
loss rate and the fine structure splitting is varied while keeping their
product constant. This implies the non-equivalence of the physical information
contained in the time-dependent and single-time integrated concurrence on the
one hand and the double-time integrated concurrence on the other hand.

12
The categories of this paper are: nucl-th
26
The categories of this paper are: bayes-an
20
The categories of this paper are: acc-phys
7
The categories of this paper are: hep-th
17
The categories of this paper are: q-fin
5
The categories of this paper are: gr-qc
21
The categories of this paper are: adap-org
9
The categories of this paper are: nlin
27
The categories of this paper are: comp-gas
24
The categories of this paper are: dg-ga
22
The categories of this paper are: chao-dyn
33
The categories of this paper are: plasm-ph
2
The categories of this paper are: math
32
The categories of this paper are: atom-ph
11
The categories of this paper are: hep-lat
14
The categories of this paper are: math-ph