---
_id: '11353'
abstract:
- lang: eng
  text: Micro- and nanoscale optical or microwave cavities are used in a wide range
    of classical applications and quantum science experiments, ranging from precision
    measurements, laser technologies to quantum control of mechanical motion. The
    dissipative photon loss via absorption, present to some extent in any optical
    cavity, is known to introduce thermo-optical effects and thereby impose fundamental
    limits on precision measurements. Here, we theoretically and experimentally reveal
    that such dissipative photon absorption can result in quantum feedback via in-loop
    field detection of the absorbed optical field, leading to the intracavity field
    fluctuations to be squashed or antisquashed. A closed-loop dissipative quantum
    feedback to the cavity field arises. Strikingly, this modifies the optical cavity
    susceptibility in coherent response measurements (capable of both increasing or
    decreasing the bare cavity linewidth) and causes excess noise and correlations
    in incoherent interferometric optomechanical measurements using a cavity, that
    is parametrically coupled to a mechanical oscillator. We experimentally observe
    such unanticipated dissipative dynamics in optomechanical spectroscopy of sideband-cooled
    optomechanical crystal cavitiess at both cryogenic temperature (approximately
    8 K) and ambient conditions. The dissipative feedback introduces effective modifications
    to the optical cavity linewidth and the optomechanical scattering rate and gives
    rise to excess imprecision noise in the interferometric quantum measurement of
    mechanical motion. Such dissipative feedback differs fundamentally from a quantum
    nondemolition feedback, e.g., optical Kerr squeezing. The dissipative feedback
    itself always results in an antisqueezed out-of-loop optical field, while it can
    enhance the coexisting Kerr squeezing under certain conditions. Our result applies
    to cavity spectroscopy in both optical and superconducting microwave cavities,
    and equally applies to any dissipative feedback mechanism of different bandwidth
    inside the cavity. It has wide-ranging implications for future dissipation engineering,
    such as dissipation enhanced sideband cooling and Kerr squeezing, quantum frequency
    conversion, and nonreciprocity in photonic systems.
acknowledgement: "L.Q. acknowledges fruitful discussions with D. Vitali, R. Schnabel,
  P.K. Lam, A. Nunnenkamp, and D. Malz. This work is supported by the EUH2020 research
  and innovation programme under Grant No. 732894 (FET Proactive HOT), and the European
  Research Council through \r\nGrant No. 835329 (ExCOM-cCEO). This work was further
  supported by Swiss National Science Foundation under Grant Agreements No. 185870
  (Ambizione) and No. 204927. Samples were fabricated at the Center of MicroNanoTechnology
  (CMi) at EPFL and the Binnig and Rohrer Nanotechnology Center at IBM Research-Zurich."
article_number: '020309'
article_processing_charge: No
article_type: original
author:
- first_name: Liu
  full_name: Qiu, Liu
  id: 45e99c0d-1eb1-11eb-9b96-ed8ab2983cac
  last_name: Qiu
  orcid: 0000-0003-4345-4267
- first_name: Guanhao
  full_name: Huang, Guanhao
  last_name: Huang
- first_name: Itay
  full_name: Shomroni, Itay
  last_name: Shomroni
- first_name: Jiahe
  full_name: Pan, Jiahe
  last_name: Pan
- first_name: Paul
  full_name: Seidler, Paul
  last_name: Seidler
- first_name: Tobias J.
  full_name: Kippenberg, Tobias J.
  last_name: Kippenberg
citation:
  ama: Qiu L, Huang G, Shomroni I, Pan J, Seidler P, Kippenberg TJ. Dissipative quantum
    feedback in measurements using a parametrically coupled microcavity. <i>PRX Quantum</i>.
    2022;3(2). doi:<a href="https://doi.org/10.1103/PRXQuantum.3.020309">10.1103/PRXQuantum.3.020309</a>
  apa: Qiu, L., Huang, G., Shomroni, I., Pan, J., Seidler, P., &#38; Kippenberg, T.
    J. (2022). Dissipative quantum feedback in measurements using a parametrically
    coupled microcavity. <i>PRX Quantum</i>. American Physical Society. <a href="https://doi.org/10.1103/PRXQuantum.3.020309">https://doi.org/10.1103/PRXQuantum.3.020309</a>
  chicago: Qiu, Liu, Guanhao Huang, Itay Shomroni, Jiahe Pan, Paul Seidler, and Tobias
    J. Kippenberg. “Dissipative Quantum Feedback in Measurements Using a Parametrically
    Coupled Microcavity.” <i>PRX Quantum</i>. American Physical Society, 2022. <a
    href="https://doi.org/10.1103/PRXQuantum.3.020309">https://doi.org/10.1103/PRXQuantum.3.020309</a>.
  ieee: L. Qiu, G. Huang, I. Shomroni, J. Pan, P. Seidler, and T. J. Kippenberg, “Dissipative
    quantum feedback in measurements using a parametrically coupled microcavity,”
    <i>PRX Quantum</i>, vol. 3, no. 2. American Physical Society, 2022.
  ista: Qiu L, Huang G, Shomroni I, Pan J, Seidler P, Kippenberg TJ. 2022. Dissipative
    quantum feedback in measurements using a parametrically coupled microcavity. PRX
    Quantum. 3(2), 020309.
  mla: Qiu, Liu, et al. “Dissipative Quantum Feedback in Measurements Using a Parametrically
    Coupled Microcavity.” <i>PRX Quantum</i>, vol. 3, no. 2, 020309, American Physical
    Society, 2022, doi:<a href="https://doi.org/10.1103/PRXQuantum.3.020309">10.1103/PRXQuantum.3.020309</a>.
  short: L. Qiu, G. Huang, I. Shomroni, J. Pan, P. Seidler, T.J. Kippenberg, PRX Quantum
    3 (2022).
date_created: 2022-05-08T22:01:43Z
date_published: 2022-04-13T00:00:00Z
date_updated: 2023-08-03T07:05:00Z
day: '13'
ddc:
- '530'
department:
- _id: JoFi
doi: 10.1103/PRXQuantum.3.020309
ec_funded: 1
external_id:
  isi:
  - '000789316700001'
file:
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  creator: dernst
  date_created: 2022-05-09T07:10:51Z
  date_updated: 2022-05-09T07:10:51Z
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file_date_updated: 2022-05-09T07:10:51Z
has_accepted_license: '1'
intvolume: '         3'
isi: 1
issue: '2'
language:
- iso: eng
license: https://creativecommons.org/licenses/by/4.0/
month: '04'
oa: 1
oa_version: Published Version
project:
- _id: 257EB838-B435-11E9-9278-68D0E5697425
  call_identifier: H2020
  grant_number: '732894'
  name: Hybrid Optomechanical Technologies
publication: PRX Quantum
publication_identifier:
  eissn:
  - '26913399'
publication_status: published
publisher: American Physical Society
quality_controlled: '1'
scopus_import: '1'
status: public
title: Dissipative quantum feedback in measurements using a parametrically coupled
  microcavity
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 3
year: '2022'
...