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Quantification of entanglement against mixing is given for a system of coupled qubits under a phase damping channel. A family of pure initial joint states is defined, ranging from pure separable states to maximally entangled state. An…

Quantum Physics · Physics 2009-11-11 E. S. Cardoso , M. C. de Oliveira , K. Furuya

We discuss the estimation of channel parameters for a noisy quantum channel - the so-called Pauli channel - using finite resources. It turns out that prior entanglement considerably enhances the fidelity of the estimation when we compare it…

Quantum Physics · Physics 2009-11-07 Dietmar G. Fischer , Holger Mack , Markus A. Cirone , Matthias Freyberger

Entanglement is an essential resource for various quantum-information tasks. When a target system shares entanglement with another memory system and is stored reliably, one can use entanglement at a later time -- this is quantum memory. In…

Quantum Physics · Physics 2024-10-18 Gelo Noel M. Tabia , Chung-Yun Hsieh

Quantifying entanglement is a work in progress which is important for the active field of quantum information and computation. A measure of bipartite pure state entanglement is proposed here, named entanglement coherence, which is…

Quantum Physics · Physics 2022-02-15 Neha Pathania , Tabish Qureshi

Numerous inequalities involving moments of integrated intensities and revealing nonclassicality and entanglement in bipartite optical fields are derived using the majorization theory, non-negative polynomials, the matrix approach, as well…

Quantum Physics · Physics 2018-12-11 Jan Perina , Ievgen I. Arkhipov , Vaclav Michalek , Ondrej Haderka

Entanglement is a key resource to demonstrate quantum advantage over classical strategies. Entanglement in quantum states is one of the most well-explored areas in quantum physics. However, a rigorous approach to understanding and detecting…

Quantum Physics · Physics 2025-02-12 Shubhayan Sarkar

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 show that entangling capacities based on the Jamiolkowski isomorphism may be used to place lower bounds on the communication capacities of arbitrary bipartite unitaries. Therefore, for these definitions, the relations which have been…

Quantum Physics · Physics 2009-11-13 Dominic W. Berry

We derive an analytical lower bound for the concurrence of a bipartite quantum state in arbitrary dimension. A functional relation is established relating concurrence, the Peres-Horodecki criterion and the realignment criterion. We…

Quantum Physics · Physics 2007-05-23 Kai Chen , Sergio Albeverio , Shao-Ming Fei

We present a method to construct entanglement measures for pure states of multipartite qubit systems. The key element of our approach is an antilinear operator that we call {\em comb} in reference to the {\em hairy-ball theorem}. For qubits…

Quantum Physics · Physics 2007-05-23 Andreas Osterloh , Jens Siewert

We consider explicitly two examples of d-dimensional quantum channels with correlated noise and show that, in agreement with previous results on Pauli qubit channels, there are situations where maximally entangled input states achieve…

Quantum Physics · Physics 2007-05-23 E. Karpov , D. Daems , N. J. Cerf

Entanglement entropy is an important quantity in field theory, but its definition poses some challenges. The naive definition involves an extension of quantum field theory in which one assigns Hilbert spaces to spatial sub-regions. For…

High Energy Physics - Theory · Physics 2019-10-23 William Donnelly , Gabriel Wong

A complementarity relation is shown between the visibility of interference and bipartite entanglement in a two qubit interferometric system when the parameters of the quantum operation change for a given input state. The entanglement…

Quantum Physics · Physics 2014-12-01 A. Hosoya , A. Carlini , S. Okano

Quantifying genuine entanglement is a key task in quantum information theory. We study the quantification of genuine multipartite entanglement for four-qubit systems. Based on the concurrence of nine different classes of four-qubit states,…

Quantum Physics · Physics 2023-07-19 Meng-Li Guo , Zhi-Xiang Jin , Bo Li , Shao-Ming Fei

In this work we aim at quantifying quantum channel output similarity. In order to achieve this, we introduce the notion of quantum channel superfidelity, which gives us an upper bound on the quantum channel fidelity. This quantity is…

Quantum Physics · Physics 2018-10-12 Łukasz Pawela , Zbigniew Puchała

We investigate the generation of multipartite entangled SU(k+1) coherent states using a quantum network involving a sequence of k beam splitters. We particularly investigate the entanglement in multipartite SU(2) coherent states (k = 1). We…

Quantum Physics · Physics 2012-10-30 M. Daoud , E. B. Choubabi

The entanglement-assisted classical capacity of a quantum channel is known to provide the formal quantum generalization of Shannon's classical channel capacity theorem, in the sense that it admits a single-letter characterization in terms…

Quantum Physics · Physics 2016-05-31 Nilanjana Datta , Marco Tomamichel , Mark M. Wilde

Quantum mechanics dictates the band-structure of materials that is essential for functional electronic components. With increased miniaturization of devices, it becomes possible to exploit the full potential of quantum mechanics through the…

Quantum Physics · Physics 2022-05-26 Kasper Poulsen , Alan C. Santos , Lasse B. Kristensen , Nikolaj T. Zinner

Quantum dots are nanometer-scale semiconductor particles that exhibit size-dependent quantum mechanical properties. In this work, we investigate the dynamics of quantum correlations, quantified by the concurrence and the quantum coherence,…

In the context of entanglement in relativistic $2\to 2$ scattering described by a perturbative $S$-matrix, we derive analytically the concurrence for a mixed final state of two qubits corresponding to a discrete quantum number of the…

High Energy Physics - Phenomenology · Physics 2026-04-08 Kamila Kowalska , Enrico Maria Sessolo
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