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The entanglement content of superpositions of pairs of degenerate eigenstates of a bipartite system are considered in the case that both are also eigenstates of the $z$ component of the total angular momentum. It is shown that the von…

Quantum Physics · Physics 2019-10-09 Natalia Giovenale , Federico M. Pont , Pablo Serra , Omar Osenda

This paper introduces a numerical framework for establishing lower bounds on the conditional von-Neumann entropy in device-independent quantum cryptography and randomness extraction scenarios. Leveraging a hierarchy of semidefinite programs…

Quantum Physics · Physics 2025-08-22 Gereon Koßmann , René Schwonnek

Quantum resource theories (QRTs) provide a unified framework to analyze quantum properties as resources for achieving advantages in quantum information processing. The generalized robustness and the weight of resource have been gaining…

Quantum Physics · Physics 2024-04-24 Kohdai Kuroiwa , Ryuji Takagi , Gerardo Adesso , Hayata Yamasaki

Entanglement is the fundamental quantum property behind the now popular field of quantum transport of information. This quantum property is incompatible with the separation of a single system into two uncorrelated subsystems. Consequently,…

Statistical Mechanics · Physics 2009-11-07 Filippo Giraldi , Paolo Grigolini

By carrying out appropriate continuous quantum measurements with a family of projection operators, a unitary channel can be approximated in an arbitrary precision in the trace norm sense. In particular, the quantum Zeno effect is described…

Mathematical Physics · Physics 2013-12-10 Toru Fuda

Many quantum information measures can be written as an optimization of the quantum relative entropy between sets of states. For example, the relative entropy of entanglement of a state is the minimum relative entropy to the set of separable…

Quantum Physics · Physics 2018-08-09 Hamza Fawzi , Omar Fawzi

The von Neumann entropy of a quantum state is a central concept in physics and information theory, having a number of compelling physical interpretations. There is a certain perspective that the most fundamental notion in quantum mechanics…

Quantum Physics · Physics 2021-05-12 Gilad Gour , Mark M. Wilde

We derive a general approximate solution to the problem of minimizing the conditional entropy of a qudit-qubit system resulting from a local projective measurement on the qubit, which is valid for general entropic forms and becomes exact in…

Quantum Physics · Physics 2015-06-22 N. Gigena , R. Rossignoli

We review the geometric features of negative conditional entropy and the properties of the conditional amplitude operator proposed by Cerf and Adami for two qubit states in comparison with entanglement and nonlocality of the states. We…

Quantum Physics · Physics 2017-02-23 Nicolai Friis , Sridhar Bulusu , Reinhold A. Bertlmann

We study the use of von Neumann entropy constraints for obtaining lower bounds on the ground energy of quantum many-body systems. Known methods for obtaining certificates on the ground energy typically use consistency of local observables…

Quantum Physics · Physics 2024-06-19 Hamza Fawzi , Omar Fawzi , Samuel O. Scalet

It is known that the witness operator is useful in the detection and quantification of entangled states. This motivated us for the construction of the family of witness operators that can detect many mixed entangled states. This family of…

Quantum Physics · Physics 2024-05-28 Shruti Aggarwal , Satyabrata Adhikari

Strong subadditivity of von Neumann entropy, proved in 1973 by Lieb and Ruskai, is a cornerstone of quantum coding theory. All other known inequalities for entropies of quantum systems may be derived from it. Here we prove a new inequality…

Quantum Physics · Physics 2007-05-23 Noah Linden , Andreas Winter

The relative entropy of two n-party quantum states is an important quantity exhibiting, for example, the extent to which the two states are different. The relative entropy of the states formed by reducing two n-party to a smaller number $m$…

Quantum Physics · Physics 2017-08-02 Ben Ibinson , Noah Linden , Andreas Winter

The problem of bound entanglement detection is a challenging aspect of quantum information theory for higher dimensional systems. Here, we propose an indecomposable positive map for two-qutrit systems, which is shown to generate a class of…

TThe organization and structure of bipartite mixed-state quantum entanglement (QE) are more complex and less well understood compared to bipartite pure-state QE. Bipartite mixed-state QEs and their measures play a crucial role in both…

Quantum Physics · Physics 2025-10-14 Jing-Min Zhu

Although entanglement is a basic resource for reaching quantum advantange in many computation and information protocols, we lack a universal recipe for detecting it, with analytical results obtained for low dimensional systems and few…

Quantum Physics · Physics 2023-11-10 Claudio Sanavio , Edoardo Tignone , Elisa Ercolessi

We examine two conditions that can be used to detect bipartite entanglement, and show that they can be used to provide lower bounds on the negativity of states. We begin with two-qubit states, and then show how what was done there can be…

Quantum Physics · Physics 2024-02-14 Mark Hillery , Camilla Polvara , Vadim Oganesyan , Nada Ali

Entanglement is a special feature of the quantum world that reflects the existence of subtle, often non-local, correlations between local degrees of freedom. In topological theories such non-local correlations can be given a very intuitive…

High Energy Physics - Theory · Physics 2020-01-31 D. Melnikov , A. Mironov , S. Mironov , A. Morozov , An. Morozov

Ever since entanglement was identified as a computational and cryptographic resource, effort has been made to find an efficient way to tell whether a given density matrix represents an unentangled, or separable, state. Essentially, this is…

Data Structures and Algorithms · Computer Science 2007-05-23 Lawrence M. Ioannou

We provide a canonical form of mixed states in bipartite quantum systems in terms of a convex combination of a separable state and a, so-called, edge state. We construct entanglement witnesses for all edge states. We present a canonical…

Quantum Physics · Physics 2009-11-06 M. Lewenstein , B. Kraus , P. Horodecki , J. I. Cirac
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