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We establish the classical capacity of optical quantum channels as a sharp transition between two regimes---one which is an error-free regime for communication rates below the capacity, and the other in which the probability of correctly…

Quantum Physics · Physics 2015-03-17 Bhaskar Roy Bardhan , Raul Garcia-Patron , Mark M. Wilde , Andreas Winter

We study encodings that give the best known thresholds for the non-zero capacity of quantum channels, i.e., the upper bound for correctable noise, using an entropic approach to calculation of the threshold values. Our results show that…

Quantum Physics · Physics 2009-02-22 Jesse Fern , K. Birgitta Whaley

In this paper, capacity bounds for the two-user Interference Channel (IC) with cooperative receivers via conferencing links of finite capacities is investigated. The capacity results known for this communication scenario are limited to a…

Information Theory · Computer Science 2015-12-17 Reza K. Farsani , Amir K. Khandani

We investigate Gaussian quantum states in view of their exceptional role within the space of all continuous variables states. A general method for deriving extremality results is provided and applied to entanglement measures, secret key…

Quantum Physics · Physics 2009-11-11 Michael M. Wolf , Geza Giedke , J. Ignacio Cirac

We introduce the two user finite state compound Gaussian interference channel and characterize its capacity region to within one bit. The main contributions involve both novel inner and outer bounds. The inner bound is multilevel…

Information Theory · Computer Science 2008-05-01 Adnan Raja , Vinod M. Prabhakaran , Pramod Viswanath

Following initial work by Gregoratti and Werner [J. Mod. Optics 50, 913-933, 2003 and quant-ph/0403092] and Hayden and King [quant-ph/0409026], we study the problem of the capacity of a quantum channel assisted by a "friendly (channel)…

Quantum Physics · Physics 2017-08-01 Andreas Winter

The capacity regions of multiple-input multiple-output Gaussian Z-interference channels are established for the very strong interference and aligned strong interference cases. The sum-rate capacity of such channels is established under…

Information Theory · Computer Science 2009-11-25 Xiaohu Shang , Biao Chen , Gerhard Kramer , H. Vincent Poor

We consider a setting where a stream of qubits is processed sequentially. We derive fundamental limits on the rate at which classical information can be transmitted using qubits that decohere as they wait to be processed. Specifically, we…

Information Theory · Computer Science 2020-08-11 Prabha Mandayam , Krishna Jagannathan , Avhishek Chatterjee

The optimal rate at which information can be sent through a quantum channel when the transmitted signal must simultaneously carry some minimum amount of energy is characterized. To do so, we introduce the quantum-classical analogue of the…

Quantum Physics · Physics 2025-01-10 Bishal Kumar Das , Lav R. Varshney , Vaibhav Madhok

In this work, we study two different approaches to defining the entropy of a quantum channel. One of these is based on the von Neumann entropy of the corresponding Choi-Jamio{\l}kowski state. The second one is based on the relative entropy…

Quantum Physics · Physics 2021-08-17 Dariusz Kurzyk , Łukasz Pawela , Zbigniew Puchała

The quantum channel capacity gives the ultimate limit for the rate at which quantum data can be reliably transmitted through a noisy quantum channel. Degradable quantum channels are among the few channels whose quantum capacities are known.…

Quantum Physics · Physics 2011-03-31 Markus Grassl , Zhengfeng Ji , Zhaohui Wei , Bei Zeng

Transmitting data reliably over noisy communication channels is one of the most important applications of information theory, and well understood when the channel is accurately modelled by classical physics. However, when quantum effects…

We show an experimental procedure to certify the classical capacity for noisy qubit channels. The method makes use of a fixed bipartite entangled state, where the system qubit is sent to the channel input and the set of local measurements…

We find a tight upper bound for the classical capacity of quantum thermal noise channels that is within $1/\ln 2$ bits of Holevo's lower bound. This lower bound is achievable using unentangled, classical signal states, namely displaced…

Quantum Physics · Physics 2013-02-05 Robert Koenig , Graeme Smith

We derive an upper limit for the mixedness of single bosonic mode gaussian states propagating in dissipative channels. It is a function of the initial squeezing and temperature of the channel only. Moreover the time at which von Neumann's…

Quantum Physics · Physics 2008-08-07 Leonardo A. M. Souza , M. C. Nemes

This paper presents outerbounds for the two-user Gaussian fading broadcast channel. These outerbounds are based on Costa's entropy power inequality (Costa-EPI) and are formulated mathematically as a feasibility problem. For classes of the…

Information Theory · Computer Science 2011-02-17 Amin Jafarian , Sriram Vishwanath

This paper derives upper and lower bounds on the capacity of the multiple-input single-output free-space optical intensity channel with signal-independent additive Gaussian noise subject to both an average-intensity and a peak-intensity…

Information Theory · Computer Science 2017-10-26 Stefan M. Moser , Ligong Wang , Michèle Wigger

Evaluating the channel capacity is one of many key problems in information theory. In this work we derive rather-mild sufficient conditions under which the capacity is finite and achievable. These conditions are derived for generic,…

Information Theory · Computer Science 2015-12-18 Jihad Fahs , Ibrahim Abou-Faycal

We study the four well-known capacities of a two-parameter family of qubit Pauli channels. These are the channels which are covariant under the SO(2) group and contain the depolarizing channel as a special case. We find exact expressions…

Quantum Physics · Physics 2023-09-01 Abbas Poshtvan , Vahid Karimipour

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…

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