Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Optimum mixed-state discrimination for noisy entanglement-enhanced
  sensing   Quantum metrology utilizes nonclassical resources, such as entanglement or
squeezed light, to realize sensors whose performance exceeds that afforded by
classical-state systems. Environmental loss and noise, however, easily destroy
nonclassical resources, and thus nullify the performance advantages of most
quantum-enhanced sensors. Quantum illumination (QI) is different. It is a
robust entanglement-enhanced sensing scheme whose 6 dB performance advantage
over a coherent-state sensor of the same average transmitted photon number
survives the initial entanglement's eradication by loss and noise.
Unfortunately, an implementation of the optimum quantum receiver that would
reap QI's full performance advantage has remained elusive, owing to its having
to deal with a huge number of very noisy optical modes. We show how
sum-frequency generation (SFG) can be fruitfully applied to optimum multi-mode
Gaussian-mixed-state discrimination. Applied to QI, our analysis and numerical
evaluations demonstrate that our SFG receiver saturates QI's quantum Chernoff
bound. Moreover, augmenting our SFG receiver with a feed-forward (FF) mechanism
pushes its performance to the Helstrom bound in the limit of low signal
brightness. The FF-SFG receiver thus opens the door to optimum quantum-enhanced
imaging, radar detection, state and channel tomography, and communication in
practical Gaussian-state situations.

5
The categories of this paper are: gr-qc
1
The categories of this paper are: cs
15
The categories of this paper are: nucl-ex
6
The categories of this paper are: astro-ph
33
The categories of this paper are: plasm-ph
19
The categories of this paper are: eess
36
The categories of this paper are: cmp-lg
3
The categories of this paper are: physics
7
The categories of this paper are: hep-th
21
The categories of this paper are: adap-org
10
The categories of this paper are: q-bio
37
The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
17
The categories of this paper are: q-fin
23
The categories of this paper are: solv-int