arXiv subjects

Jakub J. Borkowski

Publications and source records attributed to Jakub J. Borkowski.

3 recordsLinked to original sources

arXiv2026

Optical downlink modeling for low-earth-orbit and medium-earth-orbit satellites under atmospheric turbulence with a quantum-state-tomography use case

This paper presents a comprehensive analysis of the link budget for free-space optical systems involving Low Earth Orbit (LEO) and Medium Earth Orbit (MEO) satellites. We develop a detailed model of the satellite-to-ground channel that accounts for the primary physical processes affecting transmittance: atmospheric absorption and scattering, free-space diffraction, and turbulence-induced fluctuations. The study introduces a general method for computing transmittance along a slant path between a satellite and an optical ground station, incorporating zenith angle, slant range, and altitude-dependent attenuation. The proposed framework is intended to support the design and evaluation of space-based optical links and serves as a critical tool for defining technical specifications in satellite communication demonstrators and simulations. Numerical estimates are provided to illustrate the magnitude of losses under typical operational conditions, including the role of aperture averaging. In addition to the link budget analysis, we introduce a satellite-based quantum use case. We propose a scheme for quantum state tomography performed on states generated by an onboard photon source on an LEO or MEO satellite and transmitted to the optical ground station. This approach enables continuous verification of the quality of quantum resources that can be used to perform quantum protocols within quantum information networks.

quant-ph↗

arXiv2026

Revisiting superradiance dynamics from single diamond nanocrystals with a physically consistent model for fluorescence decay

The paper by C. Bradac et al. [Nat. Commun. 8, 1205 (2017)] discusses room-temperature superradiance from NV color centers in diamonds. It presents a new model intended to reflect experimental characteristics of this phenomenon. To validate the model, the authors provide experimental results that are subsequently compared with numerical calculations derived from the scheme. Motivated by our own experiments with the fluorescence of similar NV samples, we attempted to create a theoretical model to accurately describe experimental systems. Initially, we aimed to incorporate the numerical equations from Bradac et al.'s paper's supplement into our own theoretical framework. However, we encountered numerous issues resulting in non-physical results such as negative photon counts or non-zero asymptotic fluorescence intensity. We identified these inconsistencies and proposed amendments to rectify them. We have developed our own framework by correctly reinterpreting the terms of the master equation. The resulting formulas produce physically meaningful results consistent with experimental data.

quant-ph↗

arXiv2024

Comment on Quantum illumination using polarization-entangled photon pairs for enhanced object detection (Opt. Express 32, 40150-40164, 2024)

The paper by K. Sengupta et al. (Opt. Express 32, 40150-40164, 2024) explores quantum illumination using polarization-entangled photon pairs for object detection in noisy environments. In this comment, we highlight fundamental flaws in the mathematical model used to describe photon loss. We argue that the treatment of photon loss and its effects on quantum entanglement is incorrect. We demonstrate that the conclusions of Sengupta et al., particularly the detection of low-reflectivity objects using quantum correlations, are unsubstantiated, as the assumed resilience of polarization entanglement to photon loss contradicts established principles of quantum information theory. We present a more rigorous framework for describing the effects of photon loss on both polarization-encoded and photon-number quantum states. Additionally, we critique the approach used in the OE article to model photon loss in free-space optical (FSO) transmission, noting that it is based on a fiber-optic model that was adopted with insufficient attribution from an earlier publication. We propose several improvements to enhance the modeling of FSO photon loss.

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