Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantum-kinetic theory of steady-state photocurrent generation in thin
  films: Coherent versus incoherent coupling   The generation of photocurrents due to coupling of electrons to both
classical and quantized electromagnetic fields in thin semiconductor films is
described within the framework of the nonequilibrium Green's function
formalism. For the coherent coupling to classical fields corresponding to
single field operator averages, an effective two-time intraband self-energy is
derived from a band decoupling procedure. The evaluation of coherent
photogeneration is performed self-consistently with the propagation of the
fields by using for the latter a transfer matrix formalism with an extinction
coefficient derived from the electronic Green's functions. For the "incoherent"
coupling to fluctuations of the quantized fields, which need to be considered
for the inclusion of spontaneous emission, the first self-consistent Born
self-energy is used, with full spatial resolution in the photon Green's
functions. These are obtained from the numerical solution of Dyson and Keldysh
equations including a nonlocal photon self-energy based on the same interband
polarization function as used for the coherent case. A comparison of the
spectral and integral photocurrent generation pattern reveals a close agreement
between coherent and incoherent coupling for the case of an ultrathin,
selectively contacted absorber layer at short circuit conditions.

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The categories of this paper are: nucl-th
15
The categories of this paper are: nucl-ex
20
The categories of this paper are: acc-phys
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The categories of this paper are: q-fin
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The categories of this paper are: solv-int
25
The categories of this paper are: patt-sol
33
The categories of this paper are: plasm-ph
11
The categories of this paper are: hep-lat
0
The categories of this paper are: hep-ph
36
The categories of this paper are: cmp-lg
31
The categories of this paper are: ao-sci
6
The categories of this paper are: astro-ph
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The categories of this paper are: eess
27
The categories of this paper are: comp-gas
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The categories of this paper are: quant-ph
3
The categories of this paper are: physics