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Autori principali: Novák, Tomáš, Guerra-Yánez, Carlos, Holubička, Matěj, Vojtěch, Josef, Blažej, Josef
Natura: Preprint
Pubblicazione: 2025
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Accesso online:https://arxiv.org/abs/2505.24071
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author Novák, Tomáš
Guerra-Yánez, Carlos
Holubička, Matěj
Vojtěch, Josef
Blažej, Josef
author_facet Novák, Tomáš
Guerra-Yánez, Carlos
Holubička, Matěj
Vojtěch, Josef
Blažej, Josef
contents Polarization-sensitive receivers for single photons are of crucial importance in various applications within the fields of quantum communication and quantum sensing, and are more commonly implemented in free-space optics rather than in optical fibers. This is primarily due to the unpredictable and varying birefringence in single-mode optical fibers. We present a method for birefringence compensation in an all-fiber detection setup that relies solely on coincidence measurements of a polarization-entangled state, or known correlations in a prepare-and-measure scenario. We define coincidence entropies as functions of the measured coincidence counts. These quantify the randomness of measurement outcomes, remain independent of the transmitted Bell state, and serve as indicators of the degree of entanglement. By leveraging coincidence entropy as a cost function in a gradient descent algorithm, we are able to align the polarization bases between two distinct polarization-sensitive receivers. Additionally, coincidence entropies can be employed to monitor the quality of entanglement transmission, thereby enhancing the system's ability to detect potential eavesdropping attempts, such as intercept-resend quantum attacks.
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publishDate 2025
record_format arxiv
spellingShingle Automated Polarization Basis Adjustment and Security Monitoring in Quantum Communication via Coincidence Entropies
Novák, Tomáš
Guerra-Yánez, Carlos
Holubička, Matěj
Vojtěch, Josef
Blažej, Josef
Quantum Physics
Polarization-sensitive receivers for single photons are of crucial importance in various applications within the fields of quantum communication and quantum sensing, and are more commonly implemented in free-space optics rather than in optical fibers. This is primarily due to the unpredictable and varying birefringence in single-mode optical fibers. We present a method for birefringence compensation in an all-fiber detection setup that relies solely on coincidence measurements of a polarization-entangled state, or known correlations in a prepare-and-measure scenario. We define coincidence entropies as functions of the measured coincidence counts. These quantify the randomness of measurement outcomes, remain independent of the transmitted Bell state, and serve as indicators of the degree of entanglement. By leveraging coincidence entropy as a cost function in a gradient descent algorithm, we are able to align the polarization bases between two distinct polarization-sensitive receivers. Additionally, coincidence entropies can be employed to monitor the quality of entanglement transmission, thereby enhancing the system's ability to detect potential eavesdropping attempts, such as intercept-resend quantum attacks.
title Automated Polarization Basis Adjustment and Security Monitoring in Quantum Communication via Coincidence Entropies
topic Quantum Physics
url https://arxiv.org/abs/2505.24071