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:2103.15766 · New Journal of Physics

Conditional preparation of non-Gaussian quantum optical states by mesoscopic measurement

Alex O. C. Davis, Mattia Walschaers, Valentina Parigi, Nicolas Treps

Published May 17, 2021• 8 citations
arXivHTMLPDF

Abstract

Abstract Non-Gaussian states of an optical field are important as a proposed resource in quantum information applications. While conditional preparation is a highly successful approach to preparing such states, their quality is limited by detector non-idealities such as dead time, narrow dynamic range, limited quantum efficiency and dark noise. Mesoscopic photon counters, with peak performance at higher photon number, offer many practical advantages over single-photon level conditioning detectors. Here we propose a novel approach involving displacement of the ancilla field into the regime where mesoscopic detectors can be used. We explore this strategy theoretically and present simulations accounting for experimental non-idealities such as loss and amplification noise, showing that precise photon-number resolution is not necessary to herald highly nonclassical states. We conclude that states with strong Wigner negativity can be prepared at high rates by this technique under experimentally attainable conditions.

DOI
10.1088/1367-2630/ac0204

Related papers

Direct Experimental Certification of Quantum Non-Gaussian Character and Wigner Function Negativity of Single-Photon Detectors

Josef Hloušek, Miroslav Ježek, Jaromı́r Fiurášek

Highly nonclassical character of optical quantum detectors, such as single-photon detectors, is essential for preparation of quantum states of light and a vast majority of applications in quantum metrology and quantum information processing. Therefore, it is both fundamentally interesting and practically relevant to investigate the nonclassical features of optical quantum measurements. Here we propose and experimentally demonstrate a procedure for direct certification of quantum non-Gaussianity and Wigner function negativity, two crucial nonclassicality levels, of photonic quantum detectors. Remarkably, we characterize the highly nonclassical properties of the detector by probing it with only two classical thermal states and a vacuum state. We experimentally demonstrate the quantum non-Gaussianity of a single-photon avalanche diode even under the presence of background noise, and we also certify the negativity of the Wigner function of this detector. Our results open the way for direct benchmarking of photonic quantum detectors with a few measurements on classical states.

arXiv:2101.03509•Physical Review Letters•Jan 27, 2021•18 citations

Interplay of squeezing and non-Gaussianity in conditional measurements with coherent input

Devibala Esakkimuthu, A. Basherrudin Mahmud Ahmed

Abstract Conditional measurement schemes, which employ linear optical elements and photon detectors, have recently become powerful tools for generating and enriching nonclassical states in single- and multi-mode scenarios. Here, the nonclassical resourcefulness of a simple single-mode conditional measurement (CM) setup, with a coherent state as one input state, is examined. Studying the output of this setup in the form of displaced qudits (DQ) simplifies the complete characterization of nonclassical resources. The figures of merit of the prepared states are evaluated through quadrature squeezing and some of the non-Gaussian measures such as the Hilbert–Schmidt distance, the quantum relative entropy and the Wigner negativity to identify the squeezing and non-Gaussianity of the states, respectively. The squeezing capacity of the DQ output is compared with the achievable squeezing in finite superposed Fock states, since DQ also constitute a finite-dimensional representation. This optimal squeezing is attained when the detector detects the single photons in the CM setup. All the studied non-Gaussian measures confirm the qualitative agreement that the non-Gaussianity of the setup is limited and does not exceed that of the input number state. The interplay of nonclassical resources between non-Gaussianity and squeezing is exemplified, showing that states exhibiting non-Gaussianity do not exhibit squeezing, and vice versa. In addition, experimental imperfections, such as photon-source impurities and detector inefficiencies, are accommodated to analyze the realistic preparation of DQ. The calculated success probabilities are around 15 % to create the maximally squeezed states under experimental conditions. It demonstrates the potential of nonclassical state generation with minimal nonclassical inputs through the CM scheme.

Physica Scripta•Jun 30, 2026•0 citations

Photon-number discrimination without a photon counter and its application to reconstructing non-Gaussian states

Helen M. Chrzanowski, J. Bernu, Ben M. Sparkes +5 more

The nonlinearity of a conditional photon-counting measurement can be used to ``de-Gaussify'' a Gaussian state of light. Here we present and experimentally demonstrate a technique for photon-number resolution using only homodyne detection. We then apply this technique to inform a conditional measurement, unambiguously reconstructing the statistics of the non-Gaussian one- and two-photon-subtracted squeezed vacuum states. Although our photon-number measurement relies on ensemble averages and cannot be used to prepare non-Gaussian states of light, its high efficiency, photon-number-resolving capabilities, and compatibility with the telecommunications band make it suitable for quantum-information tasks relying on the outcomes of mean values.

arXiv:1102.5566•Physical Review A•Nov 28, 2011•6 citations

Non-Gaussian-state generation with time-gated photon detection

Tatsuki Sonoyama, Kazuma Takahashi, Baramee Charoensombutamon +9 more

Non-Gaussian states of light, which are essential in fault-tolerant and universal optical quantum computation, are typically generated by a heralding scheme using photon detectors. Recently, it has been theoretically shown that the large timing jitter of the photon detectors deteriorates the purity of the generated non-Gaussian states [T. Sonoyama et al., Phys. Rev. A 105, 043714 (2022)]. Here, we circumvent this problem by time-gated photon detection and generate non-Gaussian states with Wigner negativity using continuous-wave light. We use a fast optical switch for time gating to effectively improve the timing jitter of a photon-number-resolving detector based on a transition edge sensor from 50 ns to 10 ns. As a result, we generate non-Gaussian states with Wigner negativity of \ensuremath{-}$0.011\ifmmode\pm\else\textpm\fi{}0.004$ $(\ensuremath{\hbar}=1)$, which cannot be observed without the time-gated photon detection method. These results confirm the effect of the timing jitter on non-Gaussian state generation experimentally for the first time. The proposed time-gated photon detection method would be useful for high-purity non-Gaussian state preparation in optical quantum information processing.

arXiv:2212.13335•Physical Review Research•Sep 5, 2023•11 citations

Certifying non-classicality and non-Gaussianity through optical parametric amplification

Mahmoud Kalash, M. H. M. Passos, Rácz, Éva +3 more

Non-Gaussian states of light are essential for numerous quantum information protocols; thus, certifying non-Gaussianity is crucial. Full quantum state tomography, commonly used for this purpose, is a complicated procedure and yields inconclusive results for strongly mixed states. Certifying non-Gaussianity through directly measurable parameters is a simpler alternative, typically achieved by measuring photon-number probabilities - either directly, using photon-number resolving detectors, or through Hanbury Brown--Twiss type measurements with single-photon detectors. Here, we demonstrate theoretically and experimentally that optical parametric amplification combined with conventional intensity detectors can effectively replace this approach without the need for photon-number resolution. In our method, we measure the mean photon number and the second-order correlation function for the amplified state. Using it, we successfully certify the non-Gaussianity of a heralded quasi-single-photon state. Since optical parametric amplification is a broadband and multimode process, our method provides a foundation for developing high-dimensional quantum technologies utilizing broadband multimode non-Gaussian states.

arXiv:2507.18296•Jul 24, 2025•0 citations

Analysis of optical quantum state preparation using photon detectors in the finite-temporal-resolution regime

Tatsuki Sonoyama, Warit Asavanant, Kosuke Fukui +3 more

Quantum state preparation is important for quantum information processing. In particular, in optical quantum computing with continuous variables, non-Gaussian states are needed for universal operation and error correction. Optical non-Gaussian states are usually generated by heralding schemes using photon detectors. In previous experiments, the temporal resolution of the photon detectors was sufficiently high relative to the time width of the quantum state, so that the conventional theory of non-Gaussian state preparation treated the detector's temporal resolution as negligible. However, when using various photon detectors, including photon-number-resolving detectors, the temporal resolution is non-negligible. In this paper, we extend the conventional theory of quantum state preparation using photon detectors to the finite-temporal-resolution regime, analyze the cases of single-photon and two-photon preparation as examples, and find that the generated states are characterized by the dimensionless parameter $B$, defined as the product of the temporal resolution of the detectors $\mathrm{\ensuremath{\Delta}}t$ and the bandwidth of the light source $\mathrm{\ensuremath{\Delta}}f$. Based on the results, $B\ensuremath{\sim}0.1$ is required to keep the purity and fidelity of the generated quantum states high.

arXiv:2201.06208•Physical Review A•Apr 22, 2022•11 citations
Abstract Non-Gaussian states of an optical field are important as a proposed resource in quantum information applications. While conditional preparation is a highly successful approach to preparing such states, their quality is limited by detector non-idealities such as dead time, narrow dynamic range, limited quantum efficiency and dark noise. Mesoscopic photon counters, with peak performance at higher photon number, offer many practical advantages over single-photon level conditioning detectors. Here we propose a novel approach involving displacement of the ancilla field into the regime where mesoscopic detectors can be used. We explore this strategy theoretically and present simulations accounting for experimental non-idealities such as loss and amplification noise, showing that precise photon-number resolution is not necessary to herald highly nonclassical states. We conclude that states with strong Wigner negativity can be prepared at high rates by this technique under experimentally attainable conditions.
Highly nonclassical character of optical quantum detectors, such as single-photon detectors, is essential for preparation of quantum states of light and a vast majority of applications in quantum metrology and quantum information processing. Therefore, it is both fundamentally interesting and practically relevant to investigate the nonclassical features of optical quantum measurements. Here we propose and experimentally demonstrate a procedure for direct certification of quantum non-Gaussianity and Wigner function negativity, two crucial nonclassicality levels, of photonic quantum detectors. Remarkably, we characterize the highly nonclassical properties of the detector by probing it with only two classical thermal states and a vacuum state. We experimentally demonstrate the quantum non-Gaussianity of a single-photon avalanche diode even under the presence of background noise, and we also certify the negativity of the Wigner function of this detector. Our results open the way for direct benchmarking of photonic quantum detectors with a few measurements on classical states.
Abstract Conditional measurement schemes, which employ linear optical elements and photon detectors, have recently become powerful tools for generating and enriching nonclassical states in single- and multi-mode scenarios. Here, the nonclassical resourcefulness of a simple single-mode conditional measurement (CM) setup, with a coherent state as one input state, is examined. Studying the output of this setup in the form of displaced qudits (DQ) simplifies the complete characterization of nonclassical resources. The figures of merit of the prepared states are evaluated through quadrature squeezing and some of the non-Gaussian measures such as the Hilbert–Schmidt distance, the quantum relative entropy and the Wigner negativity to identify the squeezing and non-Gaussianity of the states, respectively. The squeezing capacity of the DQ output is compared with the achievable squeezing in finite superposed Fock states, since DQ also constitute a finite-dimensional representation. This optimal squeezing is attained when the detector detects the single photons in the CM setup. All the studied non-Gaussian measures confirm the qualitative agreement that the non-Gaussianity of the setup is limited and does not exceed that of the input number state. The interplay of nonclassical resources between non-Gaussianity and squeezing is exemplified, showing that states exhibiting non-Gaussianity do not exhibit squeezing, and vice versa. In addition, experimental imperfections, such as photon-source impurities and detector inefficiencies, are accommodated to analyze the realistic preparation of DQ. The calculated success probabilities are around 15 % to create the maximally squeezed states under experimental conditions. It demonstrates the potential of nonclassical state generation with minimal nonclassical inputs through the CM scheme.
The nonlinearity of a conditional photon-counting measurement can be used to ``de-Gaussify'' a Gaussian state of light. Here we present and experimentally demonstrate a technique for photon-number resolution using only homodyne detection. We then apply this technique to inform a conditional measurement, unambiguously reconstructing the statistics of the non-Gaussian one- and two-photon-subtracted squeezed vacuum states. Although our photon-number measurement relies on ensemble averages and cannot be used to prepare non-Gaussian states of light, its high efficiency, photon-number-resolving capabilities, and compatibility with the telecommunications band make it suitable for quantum-information tasks relying on the outcomes of mean values.
Non-Gaussian states of light, which are essential in fault-tolerant and universal optical quantum computation, are typically generated by a heralding scheme using photon detectors. Recently, it has been theoretically shown that the large timing jitter of the photon detectors deteriorates the purity of the generated non-Gaussian states [T. Sonoyama et al., Phys. Rev. A 105, 043714 (2022)]. Here, we circumvent this problem by time-gated photon detection and generate non-Gaussian states with Wigner negativity using continuous-wave light. We use a fast optical switch for time gating to effectively improve the timing jitter of a photon-number-resolving detector based on a transition edge sensor from 50 ns to 10 ns. As a result, we generate non-Gaussian states with Wigner negativity of \ensuremath{-}$0.011\ifmmode\pm\else\textpm\fi{}0.004$ $(\ensuremath{\hbar}=1)$, which cannot be observed without the time-gated photon detection method. These results confirm the effect of the timing jitter on non-Gaussian state generation experimentally for the first time. The proposed time-gated photon detection method would be useful for high-purity non-Gaussian state preparation in optical quantum information processing.
Non-Gaussian states of light are essential for numerous quantum information protocols; thus, certifying non-Gaussianity is crucial. Full quantum state tomography, commonly used for this purpose, is a complicated procedure and yields inconclusive results for strongly mixed states. Certifying non-Gaussianity through directly measurable parameters is a simpler alternative, typically achieved by measuring photon-number probabilities - either directly, using photon-number resolving detectors, or through Hanbury Brown--Twiss type measurements with single-photon detectors. Here, we demonstrate theoretically and experimentally that optical parametric amplification combined with conventional intensity detectors can effectively replace this approach without the need for photon-number resolution. In our method, we measure the mean photon number and the second-order correlation function for the amplified state. Using it, we successfully certify the non-Gaussianity of a heralded quasi-single-photon state. Since optical parametric amplification is a broadband and multimode process, our method provides a foundation for developing high-dimensional quantum technologies utilizing broadband multimode non-Gaussian states.
Quantum state preparation is important for quantum information processing. In particular, in optical quantum computing with continuous variables, non-Gaussian states are needed for universal operation and error correction. Optical non-Gaussian states are usually generated by heralding schemes using photon detectors. In previous experiments, the temporal resolution of the photon detectors was sufficiently high relative to the time width of the quantum state, so that the conventional theory of non-Gaussian state preparation treated the detector's temporal resolution as negligible. However, when using various photon detectors, including photon-number-resolving detectors, the temporal resolution is non-negligible. In this paper, we extend the conventional theory of quantum state preparation using photon detectors to the finite-temporal-resolution regime, analyze the cases of single-photon and two-photon preparation as examples, and find that the generated states are characterized by the dimensionless parameter BBB, defined as the product of the temporal resolution of the detectors $\mathrm{\ensuremath{\Delta}}t$ and the bandwidth of the light source $\mathrm{\ensuremath{\Delta}}f$. Based on the results, $B\ensuremath{\sim}0.1$ is required to keep the purity and fidelity of the generated quantum states high.