Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Theory of Josephson Photomultipliers: Optimal Working Conditions and
  Back Action   We describe the back action of microwave-photon detection via a Josephson
photomultiplier (JPM), a superconducting qubit coupled strongly to a
high-quality microwave cavity. The back action operator depends qualitatively
on the duration of the measurement interval, resembling the regular photon
annihilation operator at short interaction times and approaching a variant of
the photon subtraction operator at long times. The optimal operating conditions
of the JPM differ from those considered optimal for processing and storing of
quantum information, in that a short $T_2$ of the JPM suppresses the cavity
dephasing incurred during measurement. Understanding this back action opens the
possibility to perform multiple JPM measurements on the same state, hence
performing efficient state tomography.

3
The categories of this paper are: physics
1
The categories of this paper are: cs
27
The categories of this paper are: comp-gas
29
The categories of this paper are: funct-an
37
The categories of this paper are: supr-con
33
The categories of this paper are: plasm-ph
2
The categories of this paper are: math
30
The categories of this paper are: q-alg
36
The categories of this paper are: cmp-lg
17
The categories of this paper are: q-fin
12
The categories of this paper are: nucl-th
11
The categories of this paper are: hep-lat
14
The categories of this paper are: math-ph
28
The categories of this paper are: alg-geom
6
The categories of this paper are: astro-ph
23
The categories of this paper are: solv-int