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The parabolic approximation is developed for high energy charged particles scattering in a bent crystal with variable curvature. The general form of parabolic equation is received for atomic chains located along coordinate axis of…

Accelerator Physics · Physics 2007-05-23 Gennady V. Kovalev

The quantum bit error rate is a key quantity in quantum communications. If the quantum channel is the atmosphere, the information is usually encoded in the polarization of a photon. A link budget is required, which takes into account the…

We investigate the reconstruction of the transmission matrix of a time-evolving atmospheric channel with an online recursive optimization routine, using wave-optics simulations. We demonstrate that this estimation technique is able to keep…

Optics · Physics 2025-04-02 Giacomo Sorelli , Douglas McDonald , Szymon Gladysz

Quantum simulation of particle phenomena is a rapidly advancing field of research. With the widespread availability of quantum simulators, a given quantum system can be simulated in numerous ways, offering flexibility in implementation and…

Quantum Physics · Physics 2025-08-06 Sandeep Joshi , Garima Rajpoot , Prashant Shukla

Previous demonstrations of free-space quantum communication in daylight have been touted as significant for the development of global-scale quantum networks. Until now, no one has carefully tuned their atmospheric channel to reproduce the…

Communications using frequency bands in the millimeter-wave range can play a key role in future generations of mobile networks. By allowing large bandwidth allocations, high carrier frequencies will provide high data rates to support the…

Networking and Internet Architecture · Computer Science 2017-05-08 Cristian Tatino , Ilaria Malanchini , Danish Aziz , Di Yuan

We consider quantum communication schemes where quantum optical signals are exchanged between a source on Earth and a satellite. The background curved spacetime affects the quantum state of the propagating photons. We employ…

Quantum Physics · Physics 2019-04-02 Jan Kohlrus , David Edward Bruschi , Ivette Fuentes

We consider the modeling of light beams propagating in highly forward-peaked turbulent media by fractional Fokker-Planck equations and their approximations by fractional Fermi pencil-beam models. We obtain an error estimate in a…

Analysis of PDEs · Mathematics 2020-12-04 Guillaume Bal , Benjamin Palacios

We develop and demonstrate methods for simulating the scattering of particle wave packets in the interacting Thirring model on digital quantum computers, with hardware implementations on up to 80 qubits. We identify low-entanglement time…

Molecular communication is an emerging paradigm for systems that rely on the release of molecules as information carriers. Communication via molecular diffusion is a popular strategy that is ubiquitous in nature and very fast over distances…

Emerging Technologies · Computer Science 2016-09-13 Adam Noel , Dimitrios Makrakis , Abdelhakim Hafid

Atmospheric turbulence, a common phenomenon in daily life, is primarily caused by the uneven heating of the Earth's surface. This phenomenon results in distorted and blurred acquired images or videos and can significantly impact downstream…

Computer Vision and Pattern Recognition · Computer Science 2024-02-13 Xijun Wang , Santiago López-Tapia , Aggelos K. Katsaggelos

Compressive sensing is used to perform high-dimensional quantum channel estimation with classical light. As an example, we perform a numerical simulation for the case of a three-dimensional classically non-separable state that is propagated…

Quantum Physics · Physics 2020-01-15 Chemist M. Mabena , Filippus S. Roux

We investigate estimation of fluctuating channels and its effect on security of continuous-variable quantum key distribution. We propose a novel estimation scheme which is based on the clusterization of the estimated transmittance data. We…

Wave propagation through waveguides, quantum wires or films with a modest amount of disorder is in the semi-ballistic regime when in the transversal direction(s) almost no scattering occurs, while in the long direction(s) there is so much…

Condensed Matter · Physics 2009-10-28 A. Mosk , Th. M. Nieuwenhuizen , C. Barnes

For coupled-channel resonance scattering we derive a model with a closed form solution for the $T$-matrix that satisfies unitarity and analyticity. The two-channel case is handled explicitly for an arbitrary number of resonances. The method…

Nuclear Theory · Physics 2009-11-07 N. E. Ligterink

This work is an extended version of the paper arXiv:0803.2669v1[math-ph], in which the main results were announced. We consider certain classical diffusion process for a wave function on the phase space. It is shown that at the time of…

Mathematical Physics · Physics 2008-12-31 E. M. Beniaminov

Advances in satellite quantum communications aim at reshaping the global telecommunication network by increasing the security of the transferred information. Here, we study the effects of atmospheric turbulence in continuous-variable…

Quantum Physics · Physics 2024-04-30 Tasio Gonzalez-Raya , Stefano Pirandola , Mikel Sanz

A transmission amplitude is considered for quantum or wave transport mediated by a single resonance coupled to the background of many chaotic states. Such a model provides a useful approach to quantify fluctuations in an established signal…

Mesoscale and Nanoscale Physics · Physics 2018-06-06 Dmitry V. Savin

We study a diffusion approximation for a model of stochastic motion of a particle in one spatial dimension. The velocity of the particle is constant but the direction of the motion undergoes random changes with a Poisson clock. Moreover,…

Functional Analysis · Mathematics 2022-04-21 Adam Bobrowski , Tomasz Komorowski

Free-space quantum key distribution links in urban environment have demanding operating needs, such as functioning in daylight and under atmospheric turbulence, which can dramatically impact their performance. Both effects are usually…