Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Fundamental Research

Nonreciprocal quantum optics: New effects and applications in quantum sensing

Ya‐Feng Jiao, Jie Wang, Qian Zhang, Hui-zu Lin, Hui Jing

Published Jan 6, 2025• 6 citations
Publisher

Abstract

Recent advancements in quantum techniques have enabled the design and fabrication of nonreciprocal optical devices that operate in the deep quantum regime, where quantum statistical properties play a crucial role. Following this trend, recent studies have focused on exploring the relationship between quantum correlations and nonreciprocity. Here, we sketch the latest theoretical and experimental advances in generating and manipulating nonreciprocal quantum correlations and the advantages of quantum nonreciprocity for applications in one-way quantum sensing. From a broader perspective, leveraging nonreciprocal quantum correlations by breaking reciprocal symmetry can provide a promising pathway for enhancing the performance of noise-tolerant quantum sensors.

DOI
10.1016/j.fmre.2024.12.018

Related papers

Non-Hermitian quantum sensing: fundamental limits and non-reciprocal advantages

Hoi-Kwan Lau, Aashish A. Clerk

Unconventional properties of non-Hermitian systems, such exceptional points, have recently been suggested as a resource for sensing. The impact of noise and utility in quantum regimes, however, remain highly debatable. In this talk, I will introduce a full theoretical framework to analyze the performance of a dispersive quantum non-Hermitian sensor; parts of our result have been included in our recent paper Lau & Clerk, Nat. Comm. 9, 4320 (2018). Our formalism fully accounts for noise effects in both classical and quantum regimes, and also fully treats a realistic and optimal measurement protocol based on coherent driving and homodyne detection. Focusing on two-mode devices, we derive fundamental bounds on the signal-to-noise (SNR) ratio for any such sensor. We use these to demonstrate that enhanced SNR ratio does not necessarily require any proximity to an exceptional point. Furthermore, we show that non-reciprocity is a powerful resource for sensing even when quantum noise exists.

Optical and Quantum Sensing and Precision Metrology•Mar 4, 2021•0 citations

Nonreciprocal Dispersive Coupling for Quantum Sensing

Dong Xie, Chunling Xu

Dispersive coupling is widely utilized for quantum information readout. Most prior studies have concentrated on reciprocal dispersive coupling. Here, we further construct nonreciprocal dispersive coupling and apply it to quantum sensing. For cavity photon number measurement, nonreciprocal dispersive coupling delivers higher precision than its reciprocal counterpart, and this advantage grows more pronounced with an increase in photon number. When directly measuring the single-photon driving strength, however, nonreciprocal dispersive coupling shows no superiority over reciprocal dispersive coupling. By converting the information of driving strength into cavity photon numbers via our proposed strategy, nonreciprocal dispersive coupling again outperforms reciprocal dispersive coupling in precision, with the advantage becoming increasingly significant at larger driving strength. This work presents a novel method to boost quantum sensing and enable the fabrication of ultra-precise quantum sensors.

quant-pharXiv:2606.04666•Jun 4, 2026•0 citations

Fundamental limits for reciprocal and nonreciprocal non-Hermitian quantum sensing

Liying Bao, Bo Qi, Daoyi Dong +1 more

Non-Hermitian dynamics has been widely studied to enhance the precision of quantum sensing; and non-reciprocity can be a powerful resource for non-Hermitian quantum sensing, as nonreciprocity allows to arbitrarily exceed the fundamental bound on the measurement rate of any reciprocal sensors. Here we establish fundamental limits on signal-to-noise ratio for reciprocal and nonreciprocal non-Hermitian quantum sensing. In particular, for two-mode linear systems with two coherent drives, an approximately attainable uniform bound on the best possible measurement rate per photon is derived for both reciprocal and nonreciprocal sensors. This bound is only related to the coupling coefficients and, in principle, can be made arbitrarily large. Our results thus demonstrate that a conventional reciprocal sensor with two drives can simulate any nonreciprocal sensor. This work also demonstrates a clear signature on how the excitation signals affect the signal-to-noise ratio in non-Hermitian quantum sensing.

arXiv:2104.10822•Physical Review A•Apr 20, 2021•57 citations

Quantum sensing with nonreciprocal couplings

Dong Xie, Chunling Xu

Nonreciprocity can not only generate quantum resources but can also shield noise and reverse interference from driving signals. We investigate the advantages of nonreciprocal coupling in sensing a driving signal. In general, we find that nonreciprocal coupling performs better than the corresponding reciprocal coupling. And we show that homodyne measurement is the optimal measurement. A single nonreciprocal coupling can increase measurement precision by up to 2 times. With the use of $N$ nonreciprocal couplings in parallel, the measurement precision can be increased by ${N}^{2}$ times compared with the corresponding reciprocal coupling. In a nonzero-temperature dissipative environment, we demonstrate that nonreciprocal quantum sensing has greater robustness regarding thermal noise than reciprocal quantum sensing.

arXiv:2407.14739•Physical Review Applied•Dec 18, 2024•7 citations

Quantum Advantage of One-Way Squeezing in Enhancing Weak-Force Sensing

Wang, Jie, Qian Zhang, Ya‐Feng Jiao +5 more

Cavity optomechanical (COM) sensors, featuring efficient light-motion couplings, have been widely used for ultra sensitive measurements of various physical quantities ranging from displacements to accelerations or weak forces. Previous works, however, have mainly focused on reciprocal COM systems. Here, we propose how to further improve the performance of quantum COM sensors by breaking reciprocal symmetry in purely quantum regime. Specifically, we consider a spinning COM resonator and show that by selectively driving it in opposite directions, highly nonreciprocal optical squeezing can emerge, which in turn provides an efficient way to surpass the standard quantum limit that otherwise exists in conventional reciprocal devices. Our work confirms that breaking reciprocal symmetry, already achieved in diverse systems well beyond spinning systems, can serve as a new strategy to further enhance the abilities of advanced quantum sensors, for applications ranging from testing fundamental physical laws to practical quantum metrology.

arXiv:2403.09979•Mar 15, 2024•0 citations

Quantum Imaging with Photon-Number Correlations

Ivano Ruo Berchera, Ivo Pietro Degiovanni

Non-classical correlations in optical beams offer the unprecedented opportunity of surpassing conventional limits of sensitivity and resolution in optical measurements and imaging, especially but not only, when a low photon flux down/single photons are measured. We review the principles quantum imaging and sensing techniques presenting some state-of-the-art achievements in the field. These quantum protocols have the potential to trigger major steps in many application ranging from radiometry to biophotonics.

Conference on Precision Electromagnetic Measurements•Jul 1, 2018•0 citations
Recent advancements in quantum techniques have enabled the design and fabrication of nonreciprocal optical devices that operate in the deep quantum regime, where quantum statistical properties play a crucial role. Following this trend, recent studies have focused on exploring the relationship between quantum correlations and nonreciprocity. Here, we sketch the latest theoretical and experimental advances in generating and manipulating nonreciprocal quantum correlations and the advantages of quantum nonreciprocity for applications in one-way quantum sensing. From a broader perspective, leveraging nonreciprocal quantum correlations by breaking reciprocal symmetry can provide a promising pathway for enhancing the performance of noise-tolerant quantum sensors.
Unconventional properties of non-Hermitian systems, such exceptional points, have recently been suggested as a resource for sensing. The impact of noise and utility in quantum regimes, however, remain highly debatable. In this talk, I will introduce a full theoretical framework to analyze the performance of a dispersive quantum non-Hermitian sensor; parts of our result have been included in our recent paper Lau & Clerk, Nat. Comm. 9, 4320 (2018). Our formalism fully accounts for noise effects in both classical and quantum regimes, and also fully treats a realistic and optimal measurement protocol based on coherent driving and homodyne detection. Focusing on two-mode devices, we derive fundamental bounds on the signal-to-noise (SNR) ratio for any such sensor. We use these to demonstrate that enhanced SNR ratio does not necessarily require any proximity to an exceptional point. Furthermore, we show that non-reciprocity is a powerful resource for sensing even when quantum noise exists.
Dispersive coupling is widely utilized for quantum information readout. Most prior studies have concentrated on reciprocal dispersive coupling. Here, we further construct nonreciprocal dispersive coupling and apply it to quantum sensing. For cavity photon number measurement, nonreciprocal dispersive coupling delivers higher precision than its reciprocal counterpart, and this advantage grows more pronounced with an increase in photon number. When directly measuring the single-photon driving strength, however, nonreciprocal dispersive coupling shows no superiority over reciprocal dispersive coupling. By converting the information of driving strength into cavity photon numbers via our proposed strategy, nonreciprocal dispersive coupling again outperforms reciprocal dispersive coupling in precision, with the advantage becoming increasingly significant at larger driving strength. This work presents a novel method to boost quantum sensing and enable the fabrication of ultra-precise quantum sensors.
Non-Hermitian dynamics has been widely studied to enhance the precision of quantum sensing; and non-reciprocity can be a powerful resource for non-Hermitian quantum sensing, as nonreciprocity allows to arbitrarily exceed the fundamental bound on the measurement rate of any reciprocal sensors. Here we establish fundamental limits on signal-to-noise ratio for reciprocal and nonreciprocal non-Hermitian quantum sensing. In particular, for two-mode linear systems with two coherent drives, an approximately attainable uniform bound on the best possible measurement rate per photon is derived for both reciprocal and nonreciprocal sensors. This bound is only related to the coupling coefficients and, in principle, can be made arbitrarily large. Our results thus demonstrate that a conventional reciprocal sensor with two drives can simulate any nonreciprocal sensor. This work also demonstrates a clear signature on how the excitation signals affect the signal-to-noise ratio in non-Hermitian quantum sensing.
Nonreciprocity can not only generate quantum resources but can also shield noise and reverse interference from driving signals. We investigate the advantages of nonreciprocal coupling in sensing a driving signal. In general, we find that nonreciprocal coupling performs better than the corresponding reciprocal coupling. And we show that homodyne measurement is the optimal measurement. A single nonreciprocal coupling can increase measurement precision by up to 2 times. With the use of NNN nonreciprocal couplings in parallel, the measurement precision can be increased by N2{N}^{2}N2 times compared with the corresponding reciprocal coupling. In a nonzero-temperature dissipative environment, we demonstrate that nonreciprocal quantum sensing has greater robustness regarding thermal noise than reciprocal quantum sensing.
Cavity optomechanical (COM) sensors, featuring efficient light-motion couplings, have been widely used for ultra sensitive measurements of various physical quantities ranging from displacements to accelerations or weak forces. Previous works, however, have mainly focused on reciprocal COM systems. Here, we propose how to further improve the performance of quantum COM sensors by breaking reciprocal symmetry in purely quantum regime. Specifically, we consider a spinning COM resonator and show that by selectively driving it in opposite directions, highly nonreciprocal optical squeezing can emerge, which in turn provides an efficient way to surpass the standard quantum limit that otherwise exists in conventional reciprocal devices. Our work confirms that breaking reciprocal symmetry, already achieved in diverse systems well beyond spinning systems, can serve as a new strategy to further enhance the abilities of advanced quantum sensors, for applications ranging from testing fundamental physical laws to practical quantum metrology.
Non-classical correlations in optical beams offer the unprecedented opportunity of surpassing conventional limits of sensitivity and resolution in optical measurements and imaging, especially but not only, when a low photon flux down/single photons are measured. We review the principles quantum imaging and sensing techniques presenting some state-of-the-art achievements in the field. These quantum protocols have the potential to trigger major steps in many application ranging from radiometry to biophotonics.