Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Transmission Estimation at the Fundamental Quantum Cram\'er-Rao Bound
  with Macroscopic Quantum Light   The field of quantum metrology seeks to apply quantum techniques and/or
resources to classical sensing approaches with the goal of enhancing the
precision in the estimation of a parameter beyond what can be achieved with
classical resources. Theoretically, the fundamental minimum uncertainty in the
estimation of a parameter for a given probing state is bounded by the quantum
Cram\'er-Rao bound. From a practical perspective, it is necessary to find
physical measurements that can saturate this fundamental limit and to show
experimentally that it is possible to perform measurements with the required
precision to do so. Here we perform experiments that saturate the quantum
Cram\'er-Rao bound for transmission estimation over a wide range of
transmissions when probing the system under study with a bright two-mode
squeezed state. To properly take into account the imperfections in the
generation of the quantum state, we extend our previous theoretical results to
incorporate the measured properties of the generated quantum state. For our
largest transmission level of 84%, we show a 62% reduction over the optimal
classical protocol in the variance in transmission estimation when probing with
a bright two-mode squeezed state with 8 dB of intensity-difference squeezing.
Given that transmission estimation is an integral part of many sensing
protocols, such as plasmonic sensing, spectroscopy, calibration of the quantum
efficiency of detectors, etc., the results presented promise to have a
significant impact on a number of applications in various fields of research.

17
The categories of this paper are: q-fin
28
The categories of this paper are: alg-geom
32
The categories of this paper are: atom-ph
5
The categories of this paper are: gr-qc
4
The categories of this paper are: cond-mat
29
The categories of this paper are: funct-an
2
The categories of this paper are: math
27
The categories of this paper are: comp-gas
18
The categories of this paper are: econ
0
The categories of this paper are: hep-ph
31
The categories of this paper are: ao-sci
12
The categories of this paper are: nucl-th
16
The categories of this paper are: stat
15
The categories of this paper are: nucl-ex
37
The categories of this paper are: supr-con
7
The categories of this paper are: hep-th