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

arXiv:2102.01058 · Optics Letters

Single-shot discrimination of coherent states beyond the standard quantum limit

Guillaume Thekkadath, S. Sempere-Llagostera, Bryn A. Bell, Raj B. Patel, M.S. Kim, Ian A. Walmsley

Published Apr 13, 2021• 5 citations
arXivHTMLPDF

Abstract

The discrimination of coherent states is a key task in optical communication and quantum key distribution protocols. In this work, we use a photon-number-resolving detector, the transition-edge sensor, to discriminate binary-phase-shifted coherent states at a telecom wavelength. Owing to its dynamic range and high efficiency, we achieve a bit error probability that unconditionally exceeds the standard quantum limit (SQL) by up to 7.7 dB. The improvement to the SQL persists for signals containing up to approximately seven photons on average and is achieved in a single shot (i.e., without measurement feedback), thus making our approach compatible with larger bandwidths.

DOI
10.1364/ol.421646

Related papers

Experimental Demonstration of a Quantum Receiver Beating the Standard Quantum Limit at Telecom Wavelength

Shuro Izumi, Jonas Schou Neergaard-Nielsen, Shigehito Miki +2 more

Discrimination of coherent states beyond the standard quantum limit (SQL) is an important task not only for quantum information processing but also for optical coherent communication. To optimize long-distance optical fiber networks, it is of practical importance to develop a quantum receiver beating the SQL and approaching the quantum bound at telecom wavelength. In this paper, we experimentally demonstrate a receiver beating the conventional SQL at telecom wavelength. Our receiver is composed of a displacement operation, a single-photon counter, and a real-time adaptive-feedback operation. By using a high-performance single-photon detector operating at the telecom wavelength, we achieve a discrimination error beyond the SQL. The demonstration in the telecom band is an enabler for quantum and classical communication beyond the SQL using a coherent state alphabet, and we envision that the technology can be used for long-distance quantum-key distribution, effective quantum-state preparation, and quantum estimation.

arXiv:2001.05902•Physical Review Applied•May 7, 2020•35 citations

Experimental Demonstration of a Quantum Receiver Beating the Standard Quantum Limit at Telecom Wavelength

Shuro Izumi, Jonas Schou Neergaard-Nielsen, Shigehito Miki +2 more

Discrimination of coherent states beyond the standard quantum limit (SQL) is an important task not only for quantum information processing but also for optical coherent communication. To optimize long-distance optical fiber networks, it is of practical importance to develop a quantum receiver beating the SQL and approaching the quantum bound at telecom wavelength. In this paper, we experimentally demonstrate a receiver beating the conventional SQL at telecom wavelength. Our receiver is composed of a displacement operation, a single-photon counter, and a real-time adaptive-feedback operation. By using a high-performance single-photon detector operating at the telecom wavelength, we achieve a discrimination error beyond the SQL. The demonstration in the telecom band is an enabler for quantum and classical communication beyond the SQL using a coherent state alphabet, and we envision that the technology can be used for long-distance quantum-key distribution, effective quantum-state preparation, and quantum estimation.

•Jan 1, 2020•31 citations

Sub-shot-noise-limit discrimination of on-off keyed coherent signals via a quantum receiver with a superconducting transition edge sensor

Kenji Tsujino, Daiji Fukuda, Go Fujii +4 more

We demonstrate a sub-shot-noise-limit discrimination of on-off keyed coherent signals by an optimal displacement quantum receiver in which a superconducting transition edge sensor is installed. Use of a transition edge sensor and a fiber beam splitter realizes high total detection efficiency and high interference visibility of the receiver and the observed average error surpasses the shot-noise-limit in a wider range of the signal power. Our technique opens up a new technology for the sub-shot-noise-limit detection of coherent signals in optical communication channels.

arXiv:1002.2819•Optics Express•Apr 1, 2010•50 citations

Robust Measurement for the Discrimination of Binary Coherent States

M. T. DiMario, F. E. Becerra

The discrimination of two nonorthogonal states is a fundamental element for secure and efficient communication. Quantum measurements of nonorthogonal coherent states can enhance information transfer beyond the limits of conventional technologies. We demonstrate a strategy for binary state discrimination based on optimized single-shot measurements with photon number resolving detection with a finite number resolution. This strategy enables a high degree of robustness to noise and imperfections while being scalable to high rates and, in principle, allows for surpassing the quantum noise limit (QNL) in practical situations. These features make the strategy inherently compatible with high-bandwidth communication and quantum information applications, providing advantages over the QNL under realistic conditions.

arXiv:1807.05199•Physical Review Letters•Jul 12, 2018•53 citations

Displacement receiver for phase-shift-keyed coherent states

Shuro Izumi, Masahiro Takeoka, Mikio Fujiwara +4 more

The quantum receiver is an important tool for overcoming the standard quantum limit (SQL) of discrimination errors in optical communication. We theoretically study the quantum receivers for discriminating ternary and quaternary phase-shift-keying coherent states in terms of average error rate and mutual information. Our receiver consists of on-off--type photon detectors and displacement operations without electrical feedforward operations. We show that for the ternary signals, the receiver shows a reasonable gain from the SQL even without feedforward. This scheme is realizable with the currently available technology. For the quaternary signals feedforward operation is crucial to overcome the SQL with imperfect devices. We also analytically examine the asymptotic limit of the performance of the proposed receiver with respect to the number of feedforward steps.

arXiv:1208.1815•Physical Review A•Oct 22, 2012•76 citations

Experimental super-resolved phase measurements with shot-noise sensitivity

Lior Cohen, D. Istrati, Liat Dovrat +1 more

The ultimate sensitivity of optical measurements is a key element of many recent works. Classically, it is mainly limited by the shot noise limit. However, a measurement setup that incorporates quantum mechanical principles can surpass the shot noise limit and reach the Heisenberg limit. Nevertheless, many of those experiments fail to break even the classical shot-noise limit. Following a recent proposal, we present here the results of optical phase measurements with a photon-number resolving detector using coherent states of up to 4200 photons on average. An additional scheme that can be implemented using standard single-photon detectors is also presented, and the results of the two schemes are compared. These measurements present deterministic single-shot sub-wavelength super-resolution up to 288 better than the optical wavelength. The results follow the classically limited sensitivity, up to 86 times better than the wavelength.

arXiv:1311.2721•Nov 12, 2013•1 citation
The discrimination of coherent states is a key task in optical communication and quantum key distribution protocols. In this work, we use a photon-number-resolving detector, the transition-edge sensor, to discriminate binary-phase-shifted coherent states at a telecom wavelength. Owing to its dynamic range and high efficiency, we achieve a bit error probability that unconditionally exceeds the standard quantum limit (SQL) by up to 7.7 dB. The improvement to the SQL persists for signals containing up to approximately seven photons on average and is achieved in a single shot (i.e., without measurement feedback), thus making our approach compatible with larger bandwidths.
Discrimination of coherent states beyond the standard quantum limit (SQL) is an important task not only for quantum information processing but also for optical coherent communication. To optimize long-distance optical fiber networks, it is of practical importance to develop a quantum receiver beating the SQL and approaching the quantum bound at telecom wavelength. In this paper, we experimentally demonstrate a receiver beating the conventional SQL at telecom wavelength. Our receiver is composed of a displacement operation, a single-photon counter, and a real-time adaptive-feedback operation. By using a high-performance single-photon detector operating at the telecom wavelength, we achieve a discrimination error beyond the SQL. The demonstration in the telecom band is an enabler for quantum and classical communication beyond the SQL using a coherent state alphabet, and we envision that the technology can be used for long-distance quantum-key distribution, effective quantum-state preparation, and quantum estimation.
Discrimination of coherent states beyond the standard quantum limit (SQL) is an important task not only for quantum information processing but also for optical coherent communication. To optimize long-distance optical fiber networks, it is of practical importance to develop a quantum receiver beating the SQL and approaching the quantum bound at telecom wavelength. In this paper, we experimentally demonstrate a receiver beating the conventional SQL at telecom wavelength. Our receiver is composed of a displacement operation, a single-photon counter, and a real-time adaptive-feedback operation. By using a high-performance single-photon detector operating at the telecom wavelength, we achieve a discrimination error beyond the SQL. The demonstration in the telecom band is an enabler for quantum and classical communication beyond the SQL using a coherent state alphabet, and we envision that the technology can be used for long-distance quantum-key distribution, effective quantum-state preparation, and quantum estimation.
We demonstrate a sub-shot-noise-limit discrimination of on-off keyed coherent signals by an optimal displacement quantum receiver in which a superconducting transition edge sensor is installed. Use of a transition edge sensor and a fiber beam splitter realizes high total detection efficiency and high interference visibility of the receiver and the observed average error surpasses the shot-noise-limit in a wider range of the signal power. Our technique opens up a new technology for the sub-shot-noise-limit detection of coherent signals in optical communication channels.
The discrimination of two nonorthogonal states is a fundamental element for secure and efficient communication. Quantum measurements of nonorthogonal coherent states can enhance information transfer beyond the limits of conventional technologies. We demonstrate a strategy for binary state discrimination based on optimized single-shot measurements with photon number resolving detection with a finite number resolution. This strategy enables a high degree of robustness to noise and imperfections while being scalable to high rates and, in principle, allows for surpassing the quantum noise limit (QNL) in practical situations. These features make the strategy inherently compatible with high-bandwidth communication and quantum information applications, providing advantages over the QNL under realistic conditions.
The quantum receiver is an important tool for overcoming the standard quantum limit (SQL) of discrimination errors in optical communication. We theoretically study the quantum receivers for discriminating ternary and quaternary phase-shift-keying coherent states in terms of average error rate and mutual information. Our receiver consists of on-off--type photon detectors and displacement operations without electrical feedforward operations. We show that for the ternary signals, the receiver shows a reasonable gain from the SQL even without feedforward. This scheme is realizable with the currently available technology. For the quaternary signals feedforward operation is crucial to overcome the SQL with imperfect devices. We also analytically examine the asymptotic limit of the performance of the proposed receiver with respect to the number of feedforward steps.
The ultimate sensitivity of optical measurements is a key element of many recent works. Classically, it is mainly limited by the shot noise limit. However, a measurement setup that incorporates quantum mechanical principles can surpass the shot noise limit and reach the Heisenberg limit. Nevertheless, many of those experiments fail to break even the classical shot-noise limit. Following a recent proposal, we present here the results of optical phase measurements with a photon-number resolving detector using coherent states of up to 4200 photons on average. An additional scheme that can be implemented using standard single-photon detectors is also presented, and the results of the two schemes are compared. These measurements present deterministic single-shot sub-wavelength super-resolution up to 288 better than the optical wavelength. The results follow the classically limited sensitivity, up to 86 times better than the wavelength.