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While the Unruh effect has traditionally been studied under the assumption of uniform acceleration, a simplification motivated by experimental considerations, it is not necessarily true for all non-inertial motions. We propose a novel…

General Relativity and Quantum Cosmology · Physics 2026-01-01 Manuel de Atocha Rodríguez Fernández , Alexander I. Nesterov , Gennady P. Berman , C. Moreno-González

We consider process tomography for unitary quantum channels. Given access to an unknown unitary channel acting on a $\textsf{d}$-dimensional qudit, we aim to output a classical description of a unitary that is $\varepsilon$-close to the…

Quantum Physics · Physics 2024-07-31 Jeongwan Haah , Robin Kothari , Ryan O'Donnell , Ewin Tang

This paper aims at tackling the problem of signal detection in flat-fading channels. In this context, receivers based on the expectation propagation framework appear to be very promising although presenting some critical issues. We develop…

Signal Processing · Electrical Eng. & Systems 2023-06-01 Elisa Conti , Amina Piemontese , Giulio Colavolpe , Armando Vannucci

We study the problem of communication over a compound quantum channel in the presence of entanglement. Classically such channels are modeled as a collection of conditional probability distributions wherein neither the sender nor the…

Quantum Physics · Physics 2019-03-19 Anurag Anshu , Rahul Jain , Naqueeb Ahmad Warsi

We investigate the error tolerance of quantum cryptographic protocols using $d$-level systems. In particular, we focus on prepare-and-measure schemes that use two mutually unbiased bases and a key-distillation procedure with two-way…

Quantum Physics · Physics 2007-05-23 Georgios M. Nikolopoulos , Kedar S. Ranade , Gernot Alber

In this work we study the problem of single-shot discrimination of von Neumann measurements, which we associate with measure-and-prepare channels. There are two possible approaches to this problem. The first one is simple and does not…

Quantum Physics · Physics 2018-11-08 Zbigniew Puchała , Łukasz Pawela , Aleksandra Krawiec , Ryszard Kukulski

Semiclassical models for multiple-user optical communication cannot assess the ultimate limits on reliable communication as permitted by the laws of physics. In all optical communications settings that have been analyzed within a quantum…

Quantum Physics · Physics 2011-10-21 Saikat Guha , Ivan Savov , Mark M. Wilde

In this paper, pilot-symbol-assisted transmission in cognitive radio systems over time selective flat fading channels is studied. It is assumed that causal and noncausal Wiener filter estimators are used at the secondary receiver with the…

Information Theory · Computer Science 2010-04-09 Sami Akin , Mustafa Cenk Gursoy

Underwater optical channels pose significant challenges to the security and reliability of quantum communication systems due to absorption and scattering. In this paper, we investigate the BBM92 entanglement-based quantum key distribution…

Quantum Physics · Physics 2026-05-25 Nour Rizk , Angélique Drémeau , Arnaud Coatanhay

A key technical requirement of any future quantum network is the ability to distribute quantum-entangled resources between two spatially separated points at a high rate and high fidelity. Entanglement distribution protocols based on…

Quantum Physics · Physics 2026-02-03 Nicholas Zaunders , Timothy C. Ralph

Bipartite and multipartite entangled states are basic ingredients for constructing quantum networks and their accurate verification is crucial to the functioning of the networks, especially for untrusted networks. Here we propose a simple…

Quantum Physics · Physics 2021-12-28 Yun-Guang Han , Zihao Li , Yukun Wang , Huangjun Zhu

In this paper, the problem of optimal maximum likelihood detection in a single user single-input multiple-output (SIMO) channel with phase noise at the receiver is considered. The optimal detection rules under training are derived for two…

Information Theory · Computer Science 2016-11-18 Antonios Pitarokoilis , Emil Björnson , Erik G. Larsson

The Unruh effect predicts that a uniformly accelerated observer perceives the vacuum seen by an inertial observer as a thermal bath at a temperature proportional to its proper acceleration. This phenomenon is often regarded as a flat…

General Relativity and Quantum Cosmology · Physics 2025-09-23 Yuebing Zhou , Jiawei Hu , Hongwei Yu

Herein, an atomic norm based method for accurately estimating the location and orientation of a target from millimeter-wave multi-input-multi-output (MIMO) orthogonal frequency-division multiplexing (OFDM) signals is presented. A novel…

Signal Processing · Electrical Eng. & Systems 2022-09-21 Jianxiu Li , Maxime Ferreira Da Costa , Urbashi Mitra

Several quantum radar concepts have been proposed that exploit the entanglement found in two-mode squeezed vacuum states of the electromagnetic field, the most prominent being radar based on quantum illumination. Classical radars are…

Quantum Physics · Physics 2024-10-14 Jonathan N. Blakely , Shawn D. Pethel , Kenneth R. Stewart , Kurt Jacobs

Entanglement-based quantum networks exhibit a unique flexibility in the choice of entangled resource states that are then locally manipulated by the nodes to fulfill any request in the network. Furthermore, this manipulation is not uniquely…

Quantum Physics · Physics 2025-02-04 Maria Flors Mor-Ruiz , Julius Wallnöfer , Wolfgang Dür

Sharing entanglement across quantum interconnects is fundamental for quantum information processing. We discuss a practical setting where this interconnect, modeled by a quantum channel, is used once with the aim of sharing high fidelity…

Quantum Physics · Physics 2023-10-09 Vikesh Siddhu , John Smolin

In a relativistic theory of quantum information, the possible presence of horizons is a complicating feature placing restrictions on the transmission and retrieval of information. We consider two inertial participants communicating via a…

Quantum Physics · Physics 2009-09-28 Kamil Bradler , Patrick Hayden , Prakash Panangaden

Entanglement-measurement attack is one of the most famous attacks against quantum cryptography. In quantum cryptography protocols, eavesdropping checking is an effective means to resist this attack. There are currently two commonly used…

Quantum Physics · Physics 2026-01-09 Zhaoxu Ji , Huanguo Zhang

In this paper we investigate the problem of designing a spectrum scanning strategy to detect an intelligent Invader who wants to utilize spectrum undetected for his/her unapproved purposes. To deal with this problem we model the situation…

Computer Science and Game Theory · Computer Science 2015-04-28 Andrey Garnaev , Wade Trappe