Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Fermi edge polaritons in a highly degenerate 2D electron gas: a
  diagrammatic theory   We present a theoretical study on polaritons in highly doped semiconductor
microcavities. In particular, we focus on a cavity mode that is resonant with
the absorption threshold (`Fermi edge'). In agreement with experimental
results, the strong light-matter coupling is maintained under very high doping
within our ladder diagram approximation. While the lower polariton is
qualitatively unaltered, it acquires a finite lifetime due to relaxation of the
valence band hole if the electron density exceeds a certain critical value. On
the other hand the upper polariton has a finite lifetime for all densities,
because it lies in the electron-hole continuum where no bound state exists. Our
calculations show that a narrow upper polariton quasiparticle still exists as a
result from the interplay between light-matter coupling and final state Coulomb
interaction.

26
The categories of this paper are: bayes-an
22
The categories of this paper are: chao-dyn
28
The categories of this paper are: alg-geom
16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci
6
The categories of this paper are: astro-ph
23
The categories of this paper are: solv-int
3
The categories of this paper are: physics
15
The categories of this paper are: nucl-ex
30
The categories of this paper are: q-alg
35
The categories of this paper are: mtrl-th
17
The categories of this paper are: q-fin
36
The categories of this paper are: cmp-lg
0
The categories of this paper are: hep-ph
2
The categories of this paper are: math
32
The categories of this paper are: atom-ph