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We study a nonlinear fiber optical channel impaired by cross-phase modulation and dispersion from the viewpoint of an interference channel. We characterize an outer bound on the capacity region of simultaneously achievable rate pairs,…

Information Theory · Computer Science 2021-07-06 Viswanathan Ramachandran , Astrid Barreiro , Gabriele Liga , Alex Alvarado

We show that the amount of coherent quantum information that can be reliably transmitted down a dephasing channel with memory is maximized by separable input states. In particular, we model the channel as a Markov chain or a multimode…

Quantum Physics · Physics 2007-09-09 Antonio D'Arrigo , Giuliano Benenti , Giuseppe Falci

There have been several upper bounds on the quantum capacity of the single-mode Gaussian channels with thermal noise, such as thermal attenuator and amplifier. We consider a class of attenuator and amplifier with more general noises,…

Quantum Physics · Physics 2019-05-21 Youngrong Lim , Soojoon Lee , Jaewan Kim , Kabgyun Jeong

This short and opinionated review starts with a concept of quantum signals at microwave frequencies and focuses on the principle of linear parametric amplification. The amplification process arises from the dispersive nonlinearity of…

Mesoscale and Nanoscale Physics · Physics 2017-12-11 Michel Devoret , Ananda Roy

The capacity of accelerated channel is investigated for different classes of initial states. It is shown that, the capacities of the travelling channels depend on the frame in which the accelerated channels are observed in and the initial…

Quantum Physics · Physics 2014-02-04 N. Metwally , A. Sagheer

We survey what is known about the information transmitting capacities of quantum channels, and give a proposal for how to calculate some of these capacities using linear programming.

Quantum Physics · Physics 2007-05-23 P. W. Shor

We show that a quantum-limited phase-preserving amplifier can act as a which-path information eraser when followed by heterodyne detection. This 'beam splitter with gain' implements a continuous joint measurement on the signal sources. As…

In this paper, new upper and lower bounds are proposed for the capacity of discrete-time Laguerre channel. Laguerre behavior is used to model various types of optical systems and networks such as optical amplifiers, short distance visible…

Information Theory · Computer Science 2017-01-02 Hossein Esmaeili , Jawad Salehi

We consider quantum and private communications assisted by repeaters, from the basic scenario of a single repeater chain to the general case of an arbitrarily-complex quantum network, where systems may be routed through single or multiple…

Quantum Physics · Physics 2017-08-17 Stefano Pirandola

Quantum networks entangle remote nodes by distributing quantum states, which inevitably suffer from decoherence while traversing quantum channels. Pertinent decoherence mechanisms govern the channel capacity, its reach, and the quality and…

Quantum Physics · Physics 2018-11-08 Daniel E. Jones , Brian T. Kirby , Michael Brodsky

A new bound for the quantum capacity of the $d$-dimensional depolarizing channels is presented. Our derivation makes use of a flagged extension of the map where the receiver obtains a copy of a state $\sigma_0$ whenever the messages are…

Quantum Physics · Physics 2020-07-15 Marco Fanizza , Farzad Kianvash , Vittorio Giovannetti

When classical information is sent over a quantum channel, attaining the ultimate limit to channel capacity requires the receiver to make joint measurements over long codeword blocks. For a pure-state channel, we construct a receiver that…

Quantum Physics · Physics 2015-03-17 Saikat Guha

A recent method to certify the classical capacity of quantum communication channels is applied for general damping channels in finite dimension. The method compares the mutual information obtained by coding on the computational and a…

Quantum Physics · Physics 2020-10-23 Chiara Macchiavello , Massimiliano F. Sacchi , Tito Sacchi

Quantum noise limits the sensitivity of laser interferometric gravitational-wave detectors. Given the state-of-the-art optics, the optical losses define the lower bound of the best possible quantum-limited detector sensitivity. In this…

General Relativity and Quantum Cosmology · Physics 2021-02-17 Teng Zhang , Joe Bentley , Haixing Miao

A conventional resonant detector is often subject to a trade-off between bandwidth and peak sensitivity that can be traced back to quantum Cramer-Rao Bound. Anomalous dispersion has been shown to improve it by signal amplification and is…

Quantum Physics · Physics 2020-12-03 Xiang Li , Maxim Goryachev , Yiqiu Ma , Michael E. Tobar , Chunnong Zhao , Rana X Adhikari , Yanbei Chen

The capacity of multiple-input multiple-output additive white Gaussian noise channels is investigated under peak amplitude constraints on the norm of the input vector. New insights on the capacity-achieving input distribution are presented.…

Information Theory · Computer Science 2021-05-06 Antonino Favano , Marco Ferrari , Maurizio Magarini , Luca Barletta

The optimal rate of reliable communication over a quantum channel can be enhanced by pre-shared entanglement. Whereas the enhancement may be unbounded in infinite-dimensional settings even when the input power is constrained, a…

The investigation of the ultimate limits imposed by quantum mechanics on amplification represents an important topic both on a fundamental level and from the perspective of potential applications. We propose here a novel setup for an…

Mesoscale and Nanoscale Physics · Physics 2017-08-04 C. F. Ockeloen-Korppi , T. T. Heikkilä , M. A. Sillanpää , F. Massel

This paper is concerned with the analysis of linear quantum optical networks. It provides a systematic approach to the construction a model for a given quantum network in terms of a system of quantum stochastic differential equations. This…

Quantum Physics · Physics 2014-03-26 Ian R. Petersen

In distributed communication, each transmitter prepares an ensemble of channel codes. To encode a message, a transmitter chooses a channel code individually without sharing the coding choice with other transmitters or with the receiver.…

Information Theory · Computer Science 2018-05-08 Yanru Tang , Faeze Heydaryan , Jie Luo