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All communication channels are at bottom quantum mechanical. Quantum mechanics contributes both obstacles to communication in the form of noise, and opportunities in the use of intrinsically quantum representations for information. This…

Quantum Physics · Physics 2007-05-23 Seth Lloyd

For quantum states of two subsystems, entanglement measures are related to capacities of communication tasks -- highly entangled states give higher capacity of transmitting classical as well as quantum information. However, we show that…

Quantum Physics · Physics 2010-02-05 Aditi Sen De , Ujjwal Sen

We describe two quantum channels that individually cannot send any information, even classical, without some chance of decoding error. But together a single use of each channel can send quantum information perfectly reliably. This proves…

Quantum Physics · Physics 2011-12-19 Jianxin Chen , Toby S. Cubitt , Aram W. Harrow , Graeme Smith

The operational structure of quantum couplings and entanglements is studied and classified for semifinite von Neumann algebras. We show that the classical-quantum correspondences such as quantum encodings can be treated as diagonal…

Quantum Physics · Physics 2009-11-07 V. P. Belavkin , M. Ohya

We consider properties of states of many qubits, which arise after sending certain entangled states via various noisy channels (white noise, coloured noise, local depolarization, dephasing and amplitude damping). Entanglement of these…

Quantum Physics · Physics 2015-05-13 Wieslaw Laskowski , Tomasz Paterek , Caslav Brukner , Marek Zukowski

We investigate the problem of enhancement of mutual information by encoding classical data into entangled input states of arbitrary length and show that while there is a threshold memory or correlation parameter beyond which entangled…

Quantum Physics · Physics 2009-11-13 V. Karimipour , L. Memarzadeh

We present an experiment demonstrating entanglement-enhanced classical communication capacity of a quantum channel with correlated noise. The channel is modelled by a fiber optic link exhibiting random birefringence that fluctuates on a…

Quantum Physics · Physics 2007-05-23 K. Banaszek , A. Dragan , W. Wasilewski , C. Radzewicz

The bosonic quantum channels have recently attracted a growing interest, motivated by the hope that they open a tractable approach to the generally hard problem of evaluating quantum channel capacities. These studies, however, have always…

Quantum Physics · Physics 2007-05-23 Nicolas J. Cerf , Julien Clavareau , Chiara Macchiavello , Jeremie Roland

We derive the general formula for the capacity of a noiseless quantum channel assisted by an arbitrary amount of noisy entanglement. In this capacity formula, the ratio of the quantum mutual information and the von Neumann entropy of the…

Quantum Physics · Physics 2007-05-23 Michal Horodecki , Pawel Horodecki , Ryszard Horodecki , Debbie Leung , Barbara Terhal

Entanglement behavior for different classes of two qubit systems passing through a generalized amplitude damping channel is discussed. The phenomena of sudden single, double changes and the sudden death of entanglement are reported for…

Quantum Physics · Physics 2015-06-18 Nasser Metwally

Quantum entanglements, describing truly quantum couplings, are stu died and classified from the point of view of quantum compound states. We show that c lassical-quantum correspondences such as quantum encodings can be treated as…

Quantum Physics · Physics 2007-05-23 Viacheslav P Belavkin , Masanori Ohya

We investigate super dense coding in the presence of noise, i.e. the subsystems of the entangled resource state have to pass a noisy unital quantum channel between the sender and the receiver. We discuss explicitly the case of Pauli…

Quantum Physics · Physics 2015-05-18 Zahra Shadman , Hermann Kampermann , Chiara Macchiavello , Dagmar Bruss

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

Entanglement shared between the two ends of a quantum communication channel has been shown to be a useful resource in increasing both the quantum and classical capacities for these channels. The entanglement-assisted capacities were derived…

Quantum Physics · Physics 2009-11-07 Garry Bowen

Shared entanglement can significantly amplify classical correlations between systems interacting over a limited quantum channel. A natural avenue is to use entanglement of the same dimension as the channel because this allows for unitary…

We consider the problem of trying to send a single classical bit through a noisy quantum channel when two transmissions through the channel are available as a resource. Classically, two transmissions add nothing to the receiver's capability…

Quantum Physics · Physics 2007-05-23 Charles H. Bennett , Christopher A. Fuchs , John A. Smolin

Absolutely maximally entangled states are quantum states that exhibit maximal entanglement across any bipartition, making them valuable for applications. This study investigates the behavior of qubit AME states under the influence of noisy…

Quantum Physics · Physics 2025-05-13 Maria Stawska , Jan Wójcik , Andrzej Grudka , Antoni Wójcik

We analyse the use of entangled states to perform quantum computations non locally among distant nodes in a quantum network. The complexity associated with the generation of multiparticle entangled states is quantified in terms of the…

Quantum Physics · Physics 2009-10-31 J. I. Cirac , A. Ekert , S. F. Huelga , C. Macchiavello

Entanglement subject to noise can not be shielded against decaying. But, in case of many noisy channels, the degradation can be partially prevented by using local unitary operations. We consider the effect of local noise on shared quantum…

Quantum Physics · Physics 2025-02-05 Priya Ghosh , Kornikar Sen , Ujjwal Sen

Entanglement distribution is key to the success of secure communication schemes based on quantum mechanics, and there is a strong need for an ultimate architecture able to overcome the limitations of recent proposals such as those based on…

Quantum Physics · Physics 2015-09-10 Alexander Streltsov , Remigiusz Augusiak , Maciej Demianowicz , Maciej Lewenstein