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The property of the optimal signal ensembles of entanglement assisted channel capacity is studied. A relationship between entanglement assisted channel capacity and one-shot capacity of unassisted channel is obtained. The data processing…

Quantum Physics · Physics 2009-11-10 Heng Fan

Quantum states of light are the obvious choice for communicating quantum information. To date, encoding information into the polarisation states of single photons has been widely used as these states form an natural closed two state qubit.…

Quantum Physics · Physics 2015-01-08 Peter P. Rohde , Joseph F. Fitzsimons , Alexei Gilchrist

The capacity of a channel with an energy-harvesting (EH) encoder and a finite battery remains an open problem, even in the noiseless case. A key instance of this scenario is the binary EH channel (BEHC), where the encoder has a unit-sized…

Information Theory · Computer Science 2025-02-12 Eli Shemuel , Oron Sabag , Haim H. Permuter

We study the hybrid classical-quantum version of the channel coding problem for the famous Gel'fand-Pinsker channel. In the classical setting for this channel the conditional distribution of the channel output given the channel input is a…

Information Theory · Computer Science 2015-12-15 Naqueeb Ahmad Warsi , Justin Coon

Finding the optimal encoding strategies can be challenging for communication using quantum channels, as classical and quantum capacities may be superadditive. Entanglement assistance can often simplify this task, as the…

Quantum Physics · Physics 2017-08-01 Elton Yechao Zhu , Quntao Zhuang , Peter W. Shor

The capacity and optimal signaling over a fixed Gaussian MIMO channel are considered under the joint total and per-antenna power constraints (TPC and PAC). While the general case remains an open problem, a closed-form full-rank solution is…

Information Theory · Computer Science 2018-09-05 Sergey Loyka

This paper provides new insight into the classical problem of determining both the capacity of the discrete-time channel with uniform output quantization and the capacity achieving input distribution. It builds on earlier work by Gallager…

Information Theory · Computer Science 2009-01-19 Yiyue Wu , Linda M. Davis , Robert Calderbank

We present a theoretical analysis of the capacitance of a double quantum dot in the charge and spin qubit configurations probed at high-frequencies. We find that in general the total capacitance of the system consists of two state-dependent…

Mesoscale and Nanoscale Physics · Physics 2017-01-25 R. Mizuta , R. M. Otxoa , A. C. Betz , M. F. Gonzalez-Zalba

We consider capacity of discrete-time channels with feedback for the general case where the feedback is a time-invariant deterministic function of the output samples. Under the assumption that the channel states take values in a finite…

Information Theory · Computer Science 2009-09-29 Haim Permuter , Tsachy Weissman , Andrea Goldsmith

We prove the equivalence of an arbitrary single-mode Gaussian quantum channel and a newly defined fiducial channel preceded by a phase shift and followed by a Gaussian unitary operation. This equivalence implies that the energy-constrained…

The design of error-correcting codes used in modern communications relies on information theory to quantify the capacity of a noisy channel to send information [1]. This capacity can be expressed using the mutual information between input…

Quantum Physics · Physics 2019-07-17 M. B. Hastings

We consider the problem of energy transport in a chain of coupled quantum systems with the goal of shedding light on how nonclassical resources can affect transport. We study the cases for which either coherent or incoherent energy hopping…

Quantum Physics · Physics 2021-06-03 I. Medina , S. V. Moreira , F. L. Semião

Quantum channel capacities give the fundamental performance limits for information flow over a communication channel. However, the prevalence of superadditivity is a major obstacle to understanding capacities, both quantitatively and…

Quantum Physics · Physics 2025-09-10 Graeme Smith , Peixue Wu

The calculating of the coherent information is a fundamental step in obtaining the quantum capacity of a quantum channel. We introduce orthogonal and complete code basis to evaluate the coherent information per channel use when the input is…

Quantum Physics · Physics 2010-07-28 Xiao-yu Chen , Li-zhen Jiang

We consider a broadcast scenario where one transmitter communicates with two receivers under quality-of-service constraints. The transmitter initially employs superposition coding strategies with arbitrarily distributed signals and sends…

Information Theory · Computer Science 2016-03-09 Marwan Hammouda , Sami Akin , Jürgen Peissig

A method for determination of bound state energies for an asymmetric quantum well with an arbitrary shape of the bottom is suggested. It is shown that how the equation determining the energy levels can be easily derived if one knows the…

Quantum Physics · Physics 2009-11-10 D. M. Sedrakian , A. Zh. Khachatrian

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

New upper and lower bounds are presented on the capacity of the free-space optical intensity channel. This channel is characterized by inputs that are nonnegative (representing the transmitted optical intensity) and by outputs that are…

Information Theory · Computer Science 2009-03-11 Amos Lapidoth , Stefan M. Moser , Michele A. Wigger

New upper and lower bounds are presented on the capacity of the free-space optical intensity channel. This channel is characterized by inputs that are nonnegative (representing the transmitted optical intensity) and by outputs that are…

Information Theory · Computer Science 2008-05-06 Amos Lapidoth , Stefan M. Moser , Michele A. Wigger

We give a capacity formula for the classical information transmission over a noisy quantum channel, with separable encoding by the sender and limited resources provided by the receiver's pre-shared ancilla. Instead of a pure state, we…

Quantum Physics · Physics 2017-05-22 Quntao Zhuang , Elton Yechao Zhu , Peter W. Shor