English
Related papers

Related papers: Entangled states maximize the two qubit channel ca…

200 papers

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…

Sharing entanglement across quantum interconnects is fundamental for quantum information processing. We discuss a practical setting where this interconnect, modeled by a quantum channel, is used once with the aim of sharing high fidelity…

Quantum Physics · Physics 2023-10-09 Vikesh Siddhu , John Smolin

Quantum entanglement cannot be unlimitedly shared among arbitrary number of qubits. Larger the number of entangled pairs in an N-qubit system, smaller the degree of bi-partite entanglement is. We analyze a system of N qubits in which an…

Quantum Physics · Physics 2009-11-06 Masato Koashi , Vladimir Buzek , Nobuyuki Imoto

We consider a quantum system with a finite number of distinguishable quantum states, which may be partitioned freely by a number of quantum particles, assumed to be maximally entangled. We show that if we partition the system into a number…

The hybrid entangled states generated, e.g., in a trapped-ion or atom-cavity system, have exactly one ebit of entanglement, but are not maximally entangled. We demonstrate this by showing that they violate, but in general do not maximally…

Quantum Physics · Physics 2009-11-07 Zeng-Bing Chen , Guang Hou , Yong-De Zhang

A key goal of quantum communication is to determine the maximum number of bits shared between two quantum systems. An important example of this is in entanglement based quantum key distribution (QKD) schemes. A realistic treatment of this…

Quantum Physics · Physics 2015-06-04 Thomas Brougham , Stephen M. Barnett

We design a series of quantum circuits that generate absolute maximally entangled (AME) states to benchmark a quantum computer. A relation between graph states and AME states can be exploited to optimize the structure of the circuits and…

Quantum Physics · Physics 2019-09-02 Alba Cervera-Lierta , José Ignacio Latorre , Dardo Goyeneche

Unital quantum channels, defined by their property of leaving the maximally mixed state invariant, form an important class of quantum operations. A distinguished subset of these channels can be represented as a probabilistic mixture of…

Quantum Physics · Physics 2026-03-19 Charlotte Bäcker , Konstantin Beyer , Walter T. Strunz

We define the binding entanglement channel as the quantum channel through which quantum information cannot be reliably transmitted, but which can be used to share bound entanglement. We provide a characterization of such class of channels.…

Quantum Physics · Physics 2015-06-26 Pawel Horodecki , Michal Horodecki , Ryszard Horodecki

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

Entanglement serves as a fundamental resource for various quantum information processing tasks. Fidelity of entanglement (which measures the proximity to a maximally entangled state) and various quantum entropies are key indicators for…

Quantum Physics · Physics 2025-10-21 Komal Kumar , Bivas Mallick , Tapaswini Patro , Nirman Ganguly

We discuss and generalize multi-particle entanglement based on statistical correlations using Ursell-Mayer type of cluster coefficients. Cluster coefficients are used to distinguish different, independent entangled systems as well as those…

Quantum Physics · Physics 2009-11-15 Atul Kumar , Mangala Sunder Krishnan

Quantum resources enable us to achieve an exponential advantage in learning the properties of unknown physical systems by employing quantum memory. While entanglement with quantum memory is recognized as a necessary qualitative resource,…

Quantum Physics · Physics 2026-02-26 Minsoo Kim , Changhun Oh

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

We study maximally entangled states and fully entangled fraction in general d'\otimes d (d'\geq d) systems. Necessary and sufficient conditions for maximally entangled pure and mixed states are presented. As a natural generalization of the…

Quantum Physics · Physics 2016-10-27 Ming-Jing Zhao

Ideal dense coding protocols allow one to use prior maximal entanglement to send two bits of classical information by the physical transfer of a single encoded qubit. We investigate the case when the prior entanglement is not maximal and…

Quantum Physics · Physics 2007-05-23 S. Bose , M. B. Plenio , V. Vedral

Quantum channel capacities are fundamental to quantum information theory. Their definition, however, does not limit the computational resources of sender and receiver. In this work, we initiate the study of computational quantum capacities.…

Quantum Physics · Physics 2026-01-23 Johannes Jakob Meyer , Jacopo Rizzo , Asad Raza , Lorenzo Leone , Sofiene Jerbi , Jens Eisert

In this article we consider flagged extensions of convex combination of quantum channels, and find general sufficient conditions for the degradability of the flagged extension. An immediate application is a bound on the quantum $Q$ and…

Quantum Physics · Physics 2022-02-09 Farzad Kianvash , Marco Fanizza , Vittorio Giovannetti

Genuine entanglement is the strongest form of multipartite entanglement. Genuinely entangled pure states contain entanglement in every bipartition and as such can be regarded as a valuable resource in the protocols of quantum information…

Quantum Physics · Physics 2021-12-07 K. V. Antipin

We develop a model for a noisy communication channel in which the noise affecting consecutive transmissions is correlated. This model is motivated by fluctuating birefringence of fiber optic links. We analyze the role of entanglement of the…

Quantum Physics · Physics 2009-11-10 Jonathan Ball , Andrzej Dragan , Konrad Banaszek