Harwood, A;
Serafini, A;
(2020)
Ultimate squeezing through coherent quantum feedback.
Physical Review Research
, 2
(4)
, Article 043103. 10.1103/physrevresearch.2.043103.
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Abstract
Coherent feedback is the use of feedback loops not involving any measurements for the purpose of quantum control. This can be contrasted to measurement-based feedback where the feedback signal is directed by the result of measurements upon the system. Here, we develop a general framework to describe interferometric coherent feedback loops and prove that, under any such scheme, the steady-state squeezing of a bosonic mode subject to a rotating wave coupling with a white-noise environment and to any quadratic Hamiltonian must abide by a noise-dependent bound that reduces to the 3-dB limit at zero temperature. Such a finding is compared, at fixed dynamical parameters, with the performance of homodyne continuous monitoring of the output modes, which allows one to beat coherent feedback and the 3-dB limit under certain dynamical conditions.
Type: | Article |
---|---|
Title: | Ultimate squeezing through coherent quantum feedback |
Open access status: | An open access version is available from UCL Discovery |
DOI: | 10.1103/physrevresearch.2.043103 |
Publisher version: | https://doi.org/10.1103/PhysRevResearch.2.043103 |
Language: | English |
Additional information: | ©2021 American Physical Society. Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license (https://creativecommons.org/licenses/by/4.0/). |
UCL classification: | UCL UCL > Provost and Vice Provost Offices UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
URI: | https://discovery.ucl.ac.uk/id/eprint/10128005 |




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