Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: THz driven quantum wells: Coulomb interactions and Stark shifts in the
  ultrastrong coupling regime   We investigate the near infrared interband absorption of semiconductor
quantum wells driven by intense terahertz radiation in the regime of
ultrastrong coupling, where the Rabi frequency is a significant fraction of the
frequency of the strongly driven transition. With the driving frequency tuned
just below the lowest frequency transition between valence subbands, a
particularly interesting phenomenon is observed. As the THz power increases, a
new peak emerges above the frequency of the undriven exciton peak which grows
and eventually becomes the larger of the two. This reversal of relative peak
intensity is inconsistent with the Autler-Townes effect in a three-state system
while within the rotating wave approximation (RWA). In the samples
investigated, the Bloch-Siegert shift (associated with abandoning the RWA),
exciton binding energy, the Rabi energy, and non-resonant AC Stark effects are
all of comparable magnitude. Solution of a semiconductor Bloch model with one
conduction and multiple valence subbands indicates that the AC Stark effect is
predominantly responsible for the observed phenomenon.

15
The categories of this paper are: nucl-ex
17
The categories of this paper are: q-fin
13
The categories of this paper are: quant-ph
9
The categories of this paper are: nlin
26
The categories of this paper are: bayes-an
34
The categories of this paper are: chem-ph
23
The categories of this paper are: solv-int
3
The categories of this paper are: physics
10
The categories of this paper are: q-bio
36
The categories of this paper are: cmp-lg
6
The categories of this paper are: astro-ph
0
The categories of this paper are: hep-ph
16
The categories of this paper are: stat
14
The categories of this paper are: math-ph
20
The categories of this paper are: acc-phys
30
The categories of this paper are: q-alg