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We initiate the study of passive environment-assisted communication via a quantum channel, modeled as a unitary interaction between the information carrying system and an environment. In this model, the environment is controlled by a…

Quantum Physics · Physics 2016-03-25 Siddharth Karumanchi , Stefano Mancini , Andreas Winter , Dong Yang

Elucidating a connection with nonlinear Fourier analysis, we extend a well known algorithm in quantum signal processing to represent measurable signals by square summable sequences. Each coefficient of the sequence is Lipschitz continuous…

Quantum Physics · Physics 2024-06-04 Michel Alexis , Gevorg Mnatsakanyan , Christoph Thiele

An ordering between the quantum states emerging from a single mode gauge-covariant bosonic Gaussian channel is proven. Specifically, we show that within the set of input density matrices with the same given spectrum, the element passive…

Quantum Physics · Physics 2016-04-25 Giacomo De Palma , Dario Trevisan , Vittorio Giovannetti

We propose and investigate a method of error detection and noise correction for bosonic linear networks using a method of unitary averaging. The proposed error averaging does not rely on ancillary photons or control and feed-forward…

Quantum Physics · Physics 2018-02-21 Ryan J. Marshman , Austin P. Lund , Peter P. Rohde , Timothy C. Ralph

The nonclassicality of photon-added coherent fields in the thermal channel is investigated by exploring the volume of the negative part of the Wigner function which reduces with the dissipative time. The Wigner functions become positive…

Quantum Physics · Physics 2015-06-26 Shang-Bin Li , Justin Liu , Xu-Bo Zou , Guang-Can Guo

The action of qubit channels on projective measurements on a qubit state is used to establish an equivalence between channels and properties of generalized measurements characterized by bias and sharpness parameters. This can be interpreted…

Quantum Physics · Physics 2021-11-03 Javid Naikoo , Subhashish Banerjee , A. K. Pan , Sibasish Ghosh

A stochastic model for a continuous photon counting and heterodyne measurement of a coherent source is proposed. A nonlinear filtering equation for the posterior state of a single-mode field in a cavity is derived by using the methods of…

Quantum Physics · Physics 2015-06-05 A. Dabrowska , P. Staszewski

We present an optical filter that transmits photon pairs only if they share the same horizontal or vertical polarization, without decreasing the quantum coherence between these two possibilities. Various applications for entanglement…

Quantum Physics · Physics 2016-09-08 Holger F. Hofmann , Shigeki Takeuchi

Creating stable superposed states of matter is one of the most intriguing aspects of quantum physics, leading to a variety of counter-intuitive scenarios along with a possibility of restructuring the way we understand, process and…

Atomic Physics · Physics 2018-11-13 Arif Warsi Laskar , Niharika Singh , Pratik Adhikary , Arunabh Mukherjee , Saikat Ghosh

In the framework of open quantum systems, we study the dynamics of a static polarizable two-level atom interacting with a bath of fluctuating vacuum electromagnetic field and explore under which conditions the coherence of the open quantum…

Quantum Physics · Physics 2016-03-23 Xiaobao Liu , Zehua Tian , Jieci Wang , Jiliang Jing

We report that under some specific conditions a single qubit model weakly interacting with information environments can be referred to as a quantum classifier. We exploit the additivity and the divisibility properties of the completely…

Quantum Physics · Physics 2019-05-01 Deniz Türkpençe , Tahir Çetin Akıncı , Serhat Şeker

This paper surveys some recent results on the theory of quantum linear systems and presents them within a unified framework. Quantum linear systems are a class of systems whose dynamics, which are described by the laws of quantum mechanics,…

Quantum Physics · Physics 2016-03-17 Ian R. Petersen

The kinematics of many systems encountered in robotics, mechatronics, and avionics are naturally posed on homogeneous spaces; that is, their state lies in a smooth manifold equipped with a transitive Lie group symmetry. This paper proposes…

Systems and Control · Electrical Eng. & Systems 2026-01-19 Pieter van Goor , Tarek Hamel , Robert Mahony

We examine the complementarity among coherence (visibility), predictability, and entanglement for qubit and qutrit systems subjected to noisy quantum channels. Using the system-path entanglement framework, analytical expressions for all…

Quantum Physics · Physics 2025-12-01 Pratidhwani Swain , Ramita Sarkar , Sukanta K. Tripathy , Prasanta K. Panigrahi

In this paper, we analyse the quantum coherence behaviors of a single qubit in the relativistic regime beyond the single-mode approximation. Firstly, we investigate the freezing condition of quantum coherence in fermionic system. We also…

Quantum Physics · Physics 2019-05-01 Zhiming Huang , Haozhen Situ , Cai Zhang

Quantum nonlinear operations for harmonic oscillator systems play a key role in the development of analog quantum simulators and computers. Since a variety of strong highly nonlinear operations are unavailable in the existing physical…

Quantum Physics · Physics 2017-09-25 Kimin Park , Petr Marek , Radim Filip

We have analyzed theoretically the operation of the Bayesian quantum feedback of a solid-state qubit, designed to maintain perfect coherent oscillations in the qubit for arbitrarily long time. In particular, we have studied the feedback…

Mesoscale and Nanoscale Physics · Physics 2010-04-05 Qin Zhang , Rusko Ruskov , Alexander N. Korotkov

There are still no interacting models of the Wightman axioms, suggesting that the axioms are too tightly drawn. Here a weakening of linearity for quantum fields is proposed, with the algebra still linear but with the quantum fields no…

Quantum Physics · Physics 2007-05-23 Peter Morgan

We design optimal interferometric schemes for implementation of two-qubit linear optical quantum filters diagonal in the computational basis. The filtering is realized by interference of the two photons encoding the qubits in a multiport…

Quantum Physics · Physics 2021-06-16 Jaromír Fiurášek , Robert Stárek , Michal Mičuda

The problem of mutual equilibration between two finite, identical quantum systems, A and B, prepared initially at different temperatures is elucidated. We show that the process of energy exchange between the two systems leads to accurate…

Statistical Mechanics · Physics 2012-06-07 A. V. Ponomarev , S. Denisov , J. Gemmer , P. Hänggi