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Related papers: Maximum privacy without coherence, zero-error

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We define the quantum zero-error capacity, a new kind of classical capacity of a noisy quantum channel. Moreover, the necessary requirement for which a quantum channel has zero-error capacity greater than zero is also given.

Quantum Physics · Physics 2007-05-23 Rex A. C. Medeiros , Francisco M. de Assis

We define here a new kind of quantum channel capacity by extending the concept of zero-error capacity for a noisy quantum channel. The necessary requirement for which a quantum channel has zero-error capacity greater than zero is given.…

Quantum Physics · Physics 2007-05-23 Rex A. C. Medeiros , Francisco M. De Assis

The zero-error capacity of quantum channels was defined as the least upper bound of rates at which classical information can be transmitted through a quantum channel with probability of error equal to zero. This paper investigates some…

Quantum Physics · Physics 2007-05-23 Rex A C Medeiros , Romain Alleaume , Gerard Cohen , Francisco M. de Assis

Privacy lies at the fundament of quantum mechanics. A coherently transmitted quantum state is inherently private. Remarkably, coherent quantum communication is not a prerequisite for privacy: there are quantum channels that are too noisy to…

Quantum Physics · Physics 2014-07-23 Debbie Leung , Ke Li , Graeme Smith , John Smolin

Quantum information theory establishes the ultimate limits on communication and cryptography in terms of channel capacities for various types of information. The private capacity is particularly important because it quantifies achievable…

Quantum Physics · Physics 2009-09-25 Graeme Smith , John A. Smolin

The zero-error capacity of a channel is the rate at which it can send information perfectly, with zero probability of error, and has long been studied in classical information theory. We show that the zero-error capacity of quantum channels…

Quantum Physics · Physics 2011-09-13 Toby S. Cubitt , Graeme Smith

Communication over a noisy quantum channel introduces errors in the transmission that must be corrected. A fundamental bound on quantum error correction is the quantum capacity, which quantifies the amount of quantum data that can be…

Quantum Physics · Physics 2009-02-20 Graeme Smith , Jon Yard

Two new classes of quantum channels, which we call more capable and less noisy, are introduced. The more capable class consists of channels such that the quantum capacities of the complementary channels to the environments are zero. The…

Quantum Physics · Physics 2012-01-26 Shun Watanabe

Recently there has been considerable activity on the subject of additivity of various quantum channel capacities. Here, we construct a family of channels with sharply bounded classical, hence private capacity. On the other hand, their…

Quantum Physics · Physics 2017-08-01 Ke Li , Andreas Winter , XuBo Zou , GuangCan Guo

The quantum capacity of a quantum channel is always smaller than the capacity of the channel for private communication. However, both quantities are given by the infinite regularization of respectively the coherent and the private…

Quantum Physics · Physics 2015-07-28 David Elkouss , Sergii Strelchuk

We study the power of quantum channels with little or no capacity for private communication. Because privacy is a necessary condition for quantum communication, one might expect that such channels would be of little use for transmitting…

Quantum Physics · Physics 2009-02-20 Graeme Smith , John Smolin

We derive a simple relation between a quantum channel's capacity to convey coherent (quantum) information and its usefulness for quantum cryptography.

Quantum Physics · Physics 2009-10-30 Benjamin Schumacher , Michael D. Westmoreland

Channel capacity describes the size of the nearly ideal channels, which can be obtained from many uses of a given channel, using an optimal error correcting code. In this paper we collect and compare minor and major variations in the…

Quantum Physics · Physics 2009-11-10 Dennis Kretschmann , Reinhard F Werner

A formula for the capacity of a quantum channel for transmitting private classical information is derived. This is shown to be equal to the capacity of the channel for generating a secret key, and neither capacity is enhanced by forward…

Quantum Physics · Physics 2007-05-23 I. Devetak

The zero-error classical capacity of a quantum channel is the asymptotic rate at which it can be used to send classical bits perfectly, so that they can be decoded with zero probability of error. We show that there exist pairs of quantum…

Quantum Physics · Physics 2012-01-31 Toby S. Cubitt , Jianxin Chen , Aram W. Harrow

We determine both the quantum and the private capacities of low-noise quantum channels to leading orders in the channel's distance to the perfect channel. It has been an open problem for more than 20 years to determine the capacities of…

Quantum Physics · Physics 2023-12-06 Felix Leditzky , Debbie Leung , Graeme Smith

An important distinction in our understanding of capacities of classical versus quantum channels is marked by the following question: is there an algorithm which can compute (or even efficiently compute) the capacity? While there is…

Quantum Physics · Physics 2026-03-31 Archishna Bhattacharyya , Arthur Mehta , Yuming Zhao

We study various super-activation effects in the following zero-error communication scenario: One sender wants to send classical or quantum information through a noisy quantum channel to one receiver with zero probability of error. First we…

Quantum Physics · Physics 2009-06-16 Runyao Duan

We establish a strong converse bound for the private classical capacity of anti-degradable quantum channels. Specifically, we prove that this capacity is zero whenever the error $\epsilon > 0$ and privacy parameter $\delta > 0$ satisfy the…

Quantum Physics · Physics 2025-07-22 Zahra Baghali Khanian , Christoph Hirche

Channel capacities of quantum channels can be nonadditive even if one of two quantum channels has no channel capacity. We call this phenomenon \emph{activation} of the channel capacity. In this paper, we show that when we use a quantum…

Quantum Physics · Physics 2018-06-29 Jeonghoon Park , Jun Heo
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