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We present a simple model of quantum communication where a noisy quantum channel may benefit from the addition of further noise at the decoding stage. We demonstrate enhancement of the classical information capacity of an amplitude damping…

Quantum Physics · Physics 2015-06-26 Garry Bowen , Stefano Mancini

The quantum capacity of degradable quantum channels has been proven to be additive. On the other hand, there is no general rule for the behavior of quantum capacity for non-degradable quantum channels. We introduce the set of partially…

Quantum Physics · Physics 2016-11-15 Laszlo Gyongyosi

The information carrying capacity of the d-dimensional depolarizing channel is computed. It is shown that this capacity can be achieved by encoding messages as products of pure states belonging to an orthonormal basis of the state space,…

Quantum Physics · Physics 2007-05-23 C. King

Quantum communication channels differ from their classical counterparts because their capacities can be superadditive. The principle of monogamy of entanglement suggests that superadditive improvements in the transmission capacity of a…

Quantum Physics · Physics 2025-11-06 Satvik Singh , Sergii Strelchuk

Current advancements in communication equipment demand the investigation of classical information transfer over quantum channels, by encompassing realistic scenarios in finite dimensions. To address this issue, we develop a framework for…

Quantum Physics · Physics 2026-01-08 Sudipta Mondal , Pritam Halder , Saptarshi Roy , Aditi Sen De

Quantum information theory predicts that when the transmission resource is doubled in quantum channels, the amount of information transmitted can be increased more than twice by quantum channel coding technique, whereas the increase is at…

Quantum Physics · Physics 2009-11-10 M. Takeoka , M. Fujiwara , J. Mizuno , M. Sasaki

Quantum states naturally decay under noise. Many earlier works have quantified and demonstrated lower bounds on the decay rate, showing exponential decay in a wide variety of contexts. Here we study the converse question: are there uniform…

Quantum Physics · Physics 2024-01-01 Nicholas Laracuente , Graeme Smith

The nonadditivity of channel capacity is a defining feature that distinguishes quantum communication from classical communication. In the quantum realm, the channel capacity is determined by coherent information, which is defined through…

Quantum Physics · Physics 2026-05-19 Yu Guo , Bo-Xuan Wang , Xiao-Min Hu , Yun-Feng Huang , Chuan-Feng Li , Guang-Can Guo , Bi-Heng Liu

Classical communication capacity of a channel can be enhanced either through a device called a 'quantum switch' or by putting the channel in a quantum superposition. The gains in the two cases, although different, have their origin in the…

Quantum Physics · Physics 2020-01-27 Nicolas Loizeau , Alexei Grinbaum

The capacity of a channel is known to be equivalent to the highest rate at which it can generate entanglement. Analogous to entanglement, the notion of a causality measure characterises the temporal aspect of quantum correlations. Despite…

Quantum Physics · Physics 2020-02-24 Robert Pisarczyk , Zhikuan Zhao , Yingkai Ouyang , Vlatko Vedral , Joseph F. Fitzsimons

For a continuous-input-continuous-output arbitrarily distributed quantum channel carrying classical information, the channel capacity can be computed in terms of the distribution of the channel envelope, received signal strength over a…

Information Theory · Computer Science 2022-06-09 Mouli Chakraborty , Harun Siljak , Indrakshi Dey , Nicola Marchetti

Recent studies have shown that quantum information may be effectively transmitted by a finite collection of completely depolarizing channels in a coherent superposition of different orders, via an operation known as the quantum $\tt…

Quantum Physics · Physics 2024-07-04 Zhen Wu , James Fullwood , Zhihao Ma , Siqi Zhou , Qi Zhao , Giulio Chiribella

We demonstrate superadditivity of one-shot zero-error classical capacity in an asymmetric communication setting where a noisy classical channel is used in parallel with a perfect quantum channel. Each channel individually supports only a…

Quantum Physics · Physics 2026-02-10 Ambuj , Anushko Chattopadhyay , Kunika Agarwal , Rakesh Das , Amit Mukherjee

We introduce potential capacities of quantum channels in an operational way and provide upper bounds for these quantities, which quantify the ultimate limit of usefulness of a channel for a given task in the best possible context.…

Quantum Physics · Physics 2016-02-17 Andreas Winter , Dong Yang

We present an upper bound for the quantum channel capacity that is both additive and convex. Our bound can be interpreted as the capacity of a channel for high-fidelity quantum communication when assisted by a family of channels that have…

Quantum Physics · Physics 2008-08-28 Graeme Smith , John A. Smolin , Andreas Winter

Entangled inputs can enhance the capacity of quantum channels, this being one of the consequences of the celebrated result showing the non-additivity of several quantities relevant for quantum information science. In this work, we answer…

Quantum Physics · Physics 2015-05-20 Fernando G. S. L. Brandao , Jens Eisert , Michal Horodecki , Dong Yang

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…

The classical product state capacity of a noisy quantum channel with memory is investigated. A forgetful noise-memory channel is constructed by Markov switching between two depolarizing channels which introduces non-Markovian noise…

Quantum Physics · Physics 2009-06-23 Jeroen Wouters , Ismail Akhalwaya , Mark Fannes , Francesco Petruccione

We calculate the quantum capacity of an amplitude-damping channel with time correlated Markov noise, for two channel uses. Our results show that memory of the channel increases it's ability to transmit quantum information significantly. We…

Quantum Physics · Physics 2017-07-03 Rabia Jahangir , Nigum Arshed , A. H. Toor

With the rapid deployment of quantum computers and quantum satellites, there is a pressing need to design and deploy quantum and hybrid classical-quantum networks capable of exchanging classical information. In this context, we conduct the…

Quantum Physics · Physics 2023-06-29 Indrakshi Dey , Harun Siljak , Nicola Marchetti