arXiv subjects

Pere Munar-Vallespir

Publications and source records attributed to Pere Munar-Vallespir.

4 recordsLinked to original sources

arXiv2025

Quantum Limits of LEO Satellite Beacon Reading

We study the quantum limits of the ELROI beacon concept introduced by Holmes, Weaver, and Palmer. In this concept, a satellite continuously emits a weak optical signal to broadcast its identity. Via analysis of the fundamental limits on communication introduced by Shannon, Gordon, and Holevo, we demonstrate that in such scenarios, incorporating quantum technology into the design of a ground station significantly enhances performance. Specifically, the Time-To-Read the beacon signal and thereby identify the satellite is greatly reduced in situations where weather conditions obstruct the signal, allowing the Active Time Window, during which the satellite can be utilized for subsequent network operations, to be extended by nearly a factor of 20. In this particular case, the quantum technology concept that is employed is the so-called Joint Detector Receiver, which is a system aiming to operate at the Gordon-Holevo limit by performing joint quantum operations on sequences of incoming signals.

quant-ph↗

arXiv2025

Infinite-fold Asymptotic Quantum Advantage in Classical Correlation Sensing

We study the hypothesis testing problem of distinguishing between correlated thermal noise and uncorrelated thermal noise of the same average energy on $K$ detectors in asymptotic asymmetric hypothesis testing. We compare the performance of heterodyne or homodyne detection with classical post-processing, the most general quantum strategy (involving any arbitrary measurement), and a simple strategy involving a photonic chip and On-Off detection. When the average received energy per detector goes to zero, the photonic chip strategy asymptotically achieves the optimal decrease in the error, while heterodyne/homodyne measurements do not. Thus, we show that linear optics and On-Off measurement are enough to achieve better detection than classical methods when detecting correlations in thermal optical signals.

quant-ph↗

arXiv2024

Joint Communication and Eavesdropper Detection on the Lossy Bosonic Channel

We study the problem of joint communication and detection of wiretapping on an optical fiber from a quantum perspective. Our system model describes a communication link that is capable of transmitting data under normal operating conditions and raising a warning at the transmitter side in case of eavesdropping. It contributes to a unified modelling approach, based on which established quantum communication paradigms like quantum key distribution can be compared to other approaches offering similar functionality.

quant-ph↗

arXiv2024

Joint Communication and Sensing over the Lossy Bosonic Quantum Channel

We study the problem of joint communication and sensing for data transmission systems using optimal quantum instruments in order to transmit data and, at the same time, estimate environmental parameters. In particular we consider the specific but at the same time generic case of a noiseless bosonic classical-quantum channel where part of the transmitted light is reflected back to the transmitter. While sending messages to the receiver, the transmitter tries at the same time to estimate the reflectivity of the channel. Extending earlier results on similar but finite-dimensional systems, we are able to characterize optimal tradeoffs between communication and detection rates. We also compare quantum performance to analogous classical models, quantifying the quantum advantage.

quant-ph↗