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:1710.09577 · Physical Review A

Squeezing-enhanced phase-shift-keyed binary communication in noisy channels

Giovanni Chesi, Stefano Olivares, Matteo G. A. Paris

Published Mar 15, 2018• 27 citations
arXivHTMLPDF

Abstract

We address binary phase-shift-keyed communication channels based on Gaussian states and prove that squeezing improves state discrimination at fixed energy of the channel, and also in the presence of phase diffusion. We then assess performances of homodyne detection against the ultimate quantum limits to discrimination and show that homodyning achieves optimality in the large-noise regime. Finally, we consider noise in the preparation of the seed signal (before phase encoding) and show that, also in this case, squeezing may improve state discrimination in realistic conditions.

DOI
10.1103/physreva.97.032315

Related papers

Homodyne detection as a near-optimum receiver for phase-shift-keyed binary communication in the presence of phase diffusion

Stefano Olivares, S. Cialdi, F. Castelli +1 more

We address binary optical communication channels based on phase-shift-keyed coherent signals in the presence of phase diffusion. We prove theoretically and demonstrate experimentally that a discrimination strategy based on homodyne detection is robust against this kind of noise for any value of the channel energy. Moreover, we find that a homodyne receiver beats the performance of a Kennedy receiver as the signal energy increases and achieves the Helstrom bound in the limit of large noise.

arXiv:1305.4201•Physical Review A•May 17, 2013•49 citations

Squeezing-Enhanced Phase-Shift-Keyed Binary Communication in Noisy Channels

Giovanni Chesi, Stefano Olivares, Matteo G. A. Paris

We address the use of squeezing in binary phase-shift-keyed (PSK) channels at fixed energy. In particular, we assess homodyne receivers against the Helstrom bound in the presence of phase noise. We also take into account possible imperfections in the generation of squeezing and the effect of losses during propagation. We find that squeezing is a useful resource if its amplitude is below a given threshold depending on the energy of the signals and on the properties of the channel. Squeezing enhancement is present also when phase-noise becomes large.

Italian Quantum Information Science Conference (IQIS)•Nov 25, 2019•4 citations

All-Gaussian State Discrimination Beyond the Coherent Helstrom Bound

Angus Walsh, Lorcán O. Conlon, Biveen Shajilal +5 more

A core problem in communications is the optimal discrimination of binary-phase-shift-keyed (BPSK) signals. A longstanding goal has been to reach the fundamental quantum limit, known as the Helstrom bound, for BPSK signals encoded in coherent states. However, due to technical constraints, proposals for reaching the bound remain impractical. In this letter we take an alternative approach: using only Gaussian optics - displaced squeezed states and homodyne detection - we achieve discrimination of BPSK signals with error rates below what can be achieved using coherent states and any quantum measurement.

arXiv:2510.20096•Oct 23, 2025•0 citations

Squeezing as a resource to counteract phase diffusion in optical phase estimation

Giacomo Carrara, Marco G. Genoni, S. Cialdi +2 more

We address a phase estimation scheme using Gaussian states in the presence of non-Gaussian phase noise. At variance with previous analysis, we analyze situations in which the noise occurs before encoding phase information. In particular, we study how squeezing may be profitably used before or after phase diffusion. Our results show that squeezing the probe after the noise greatly enhances the sensitivity of the estimation scheme, as witnessed by the increase of the quantum Fisher information. We then consider a realistic setup in which homodyne detection is employed at the measurement stage, and we address its optimality as well as its performance in the two different scenarios.

arXiv:2008.03161•Physical Review A•Dec 16, 2020•11 citations

Optical Phase Estimation in the Presence of Phase Diffusion

Marco G. Genoni, Stefano Olivares, Matteo G. A. Paris

The measurement problem for the optical phase has been traditionally attacked for noiseless schemes or in the presence of amplitude or detection noise. Here we address the estimation of phase in the presence of phase diffusion and evaluate the ultimate quantum limits to precision for phase-shifted Gaussian states. We look for the optimal detection scheme and derive approximate scaling laws for the quantum Fisher information and the optimal squeezing fraction in terms of the total energy and the amount of noise. We also find that homodyne detection is a nearly optimal detection scheme in the limit of very small and large noise.

arXiv:1012.1123•Physical Review Letters•Apr 14, 2011•231 citations

Discrimination of the binary coherent signal: Gaussian-operation limit and simple non-Gaussian near-optimal receivers

Masahiro Takeoka, Masahide Sasaki

We address the limit of the Gaussian operations and classical communication in the problem of quantum state discrimination. We show that the optimal Gaussian strategy for the discrimination of the binary phase shift keyed (BPSK) coherent signal is a simple homodyne detection. We also propose practical near-optimal quantum receivers that beat the BPSK homodyne limit in all areas of the signal power. Our scheme is simple and does not require realtime electrical feedback.

arXiv:0706.1038•Physical Review A•Aug 13, 2008•172 citations
We address binary phase-shift-keyed communication channels based on Gaussian states and prove that squeezing improves state discrimination at fixed energy of the channel, and also in the presence of phase diffusion. We then assess performances of homodyne detection against the ultimate quantum limits to discrimination and show that homodyning achieves optimality in the large-noise regime. Finally, we consider noise in the preparation of the seed signal (before phase encoding) and show that, also in this case, squeezing may improve state discrimination in realistic conditions.
We address the use of squeezing in binary phase-shift-keyed (PSK) channels at fixed energy. In particular, we assess homodyne receivers against the Helstrom bound in the presence of phase noise. We also take into account possible imperfections in the generation of squeezing and the effect of losses during propagation. We find that squeezing is a useful resource if its amplitude is below a given threshold depending on the energy of the signals and on the properties of the channel. Squeezing enhancement is present also when phase-noise becomes large.
A core problem in communications is the optimal discrimination of binary-phase-shift-keyed (BPSK) signals. A longstanding goal has been to reach the fundamental quantum limit, known as the Helstrom bound, for BPSK signals encoded in coherent states. However, due to technical constraints, proposals for reaching the bound remain impractical. In this letter we take an alternative approach: using only Gaussian optics - displaced squeezed states and homodyne detection - we achieve discrimination of BPSK signals with error rates below what can be achieved using coherent states and any quantum measurement.
We address a phase estimation scheme using Gaussian states in the presence of non-Gaussian phase noise. At variance with previous analysis, we analyze situations in which the noise occurs before encoding phase information. In particular, we study how squeezing may be profitably used before or after phase diffusion. Our results show that squeezing the probe after the noise greatly enhances the sensitivity of the estimation scheme, as witnessed by the increase of the quantum Fisher information. We then consider a realistic setup in which homodyne detection is employed at the measurement stage, and we address its optimality as well as its performance in the two different scenarios.
The measurement problem for the optical phase has been traditionally attacked for noiseless schemes or in the presence of amplitude or detection noise. Here we address the estimation of phase in the presence of phase diffusion and evaluate the ultimate quantum limits to precision for phase-shifted Gaussian states. We look for the optimal detection scheme and derive approximate scaling laws for the quantum Fisher information and the optimal squeezing fraction in terms of the total energy and the amount of noise. We also find that homodyne detection is a nearly optimal detection scheme in the limit of very small and large noise.