Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Quantum non-demolition measurement of microwave photons using engineered
  quadratic interactions   We present a quantum electrical circuit with Josephson junctions formed of
two anharmonic oscillators coupled with an interaction
$g\gamma_{1}^{2}\gamma_{2}^{2}$ where $\gamma_{1}$ and $\gamma_{2}$ are
position-like coordinates. This type of coupling allows the quantum
non-demolition measurement of the energy of one oscillator by monitoring the
frequency of the second oscillator. Despite the fundamental tradeoff between
the coupling strength $g$ and maximum photon storage capacity of the
oscillators, it is possible to achieve high fidelity detection of up to 10
photons over time scale of the order of microseconds. We discuss the
possibility of observing quantum jumps in the number of photons and related
applications.

20
The categories of this paper are: acc-phys
19
The categories of this paper are: eess
27
The categories of this paper are: comp-gas
31
The categories of this paper are: ao-sci
32
The categories of this paper are: atom-ph
14
The categories of this paper are: math-ph
2
The categories of this paper are: math
10
The categories of this paper are: q-bio
0
The categories of this paper are: hep-ph
5
The categories of this paper are: gr-qc
34
The categories of this paper are: chem-ph
37
The categories of this paper are: supr-con
15
The categories of this paper are: nucl-ex
6
The categories of this paper are: astro-ph
11
The categories of this paper are: hep-lat
3
The categories of this paper are: physics