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We argue from the point of view of statistical inference that the quantum relative entropy is a good measure for distinguishing between two quantum states (or two classes of quantum states) described by density matrices. We extend this…

Quantum Physics · Physics 2009-10-30 V. Vedral , M. B. Plenio , K. Jacobs , P. L. Knight

It is shown that local distinguishability of orthogonal mixed states can be completely characterized by local distinguishability of their supports irrespective of entanglement and mixedness of the states. This leads to two kinds of upper…

Quantum Physics · Physics 2012-04-20 Somshubhro Bandyopadhyay

Bound entangled states are states that are entangled but from which no entanglement can be distilled if all parties are allowed only local operations and classical communication. However, in creating these states one needs nonzero…

Quantum Physics · Physics 2009-11-10 Tzu-Chieh Wei , Joseph B. Altepeter , Paul M. Goldbart , William J. Munro

We present a package of mathematical theorems, which allow to construct multipartite entanglement criteria. Importantly, establishing bounds for certain classes of entanglement does not take an optimization over continuous sets of states.…

Quantum Physics · Physics 2013-05-30 Marcin Wieśniak , Koji Maruyama

We present a framework for deciding whether a quantum state is separable or entangled using covariance matrices of locally measurable observables. This leads to the covariance matrix criterion as a general separability criterion. We…

Quantum Physics · Physics 2008-12-03 Oleg Gittsovich , Otfried Gühne , Philipp Hyllus , Jens Eisert

In this paper, a theorem is proved that generalizes several existing amalgamation results in various ways. The main aim is to disentangle a given edge-colored amalgamated graph so that the result is a graph in which the edges are shared out…

Combinatorics · Mathematics 2017-10-12 Amin Bahmanian , Chris Rodger

It is shown that for a constant $t\in \mathbb{N}$, every simple topological graph on $n$ vertices has $O(n)$ edges if it has no two sets of $t$ edges such that every edge in one set is disjoint from all edges of the other set (i.e., the…

Combinatorics · Mathematics 2015-08-25 Andres J. Ruiz-Vargas , Andrew Suk , Csaba D. Tóth

The geometric measure of entanglement of a pure state, defined by its distance to the set of pure separable states, is extended to multipartite mixed states. We characterize the nearest disentangled mixed state to a given mixed state with…

Quantum Physics · Physics 2015-03-13 Shenglong Hu , Liqun Qi , Yisheng Song , Guofeng Zhang

In this Letter we present a new quantity that shows whether two general qubit systems are entangled, which we call harmony. It captures the notion of separability and maximal entanglement. It is also shown that harmony is monogamous for…

Quantum Physics · Physics 2019-06-25 Kento Osuga , Don N. Page

While finite graphs have tree-decompositions that efficiently distinguish all their tangles, locally finite graphs with thick ends need not have such tree-decompositions. We show that every locally finite graph without thick ends admits…

Combinatorics · Mathematics 2024-03-25 Raphael W. Jacobs , Paul Knappe

We show that if a graph contains few induced copies of a given graph then its edges are distribited unevenly.

Combinatorics · Mathematics 2007-05-23 Vladimir Nikiforov

We review the theory of multi-particle entanglement. In this book chapter we aim at briefly ``setting the coordinates'' and guiding through the extensive literature in this field. Our coordinate system chosen for this chapter has the axes…

Quantum Physics · Physics 2007-05-23 J. Eisert , D. Gross

The indistinguishability of quantum particles is widely used as a resource for the generation of entanglement. Linear quantum networks (LQNs), in which identical particles linearly evolve to arrive at multimode detectors, exploit the…

Quantum Physics · Physics 2021-12-30 Seungbeom Chin , Yong-Su Kim , Sangmin Lee

We study the normal form of multipartite density matrices. It is shown that the correlation matrix (CM) separability criterion can be improved from the normal form we obtained under filtering transformations. Based on CM criterion the…

Quantum Physics · Physics 2015-05-13 Ming Li , Shao-Ming Fei , Zhi-Xi Wang

The state of an entangled q-bit pair is specified by 15 numerical parameters that are naturally regarded as the components of two 3-vectors and a $3\times3$-dyadic. There are easy-to-use criteria to check whether a given pair of 3-vectors…

Quantum Physics · Physics 2015-06-26 Berthold-Georg Englert , Nasser Metwally

For a finite set of integers such that the first few gaps between its consecutive elements equal $a$, while the remaining gaps equal $b$, we study dense packings of its translates on the line. We obtain an explicit lower bound on the…

Combinatorics · Mathematics 2025-09-29 Alexander Natalchenko , Arsenii Sagdeev

The study on the entanglement polygon inequality of multipartite systems has attracted much attention. However, most of the results are on pure states. Here we consider the property for a class of mixed states, which are the reduced density…

Quantum Physics · Physics 2024-07-08 Xian Shi

We introduce with geometric means a density matrix decomposition of a multipartite quantum system of a finite dimension into two density matrices: a separable one, also known as the best separable approximation, and an essentially entangled…

Quantum Physics · Physics 2015-10-28 V. M. Akulin , G. A. Kabatyanski , A. Mandilara

We present a large class of indecomposable exposed positive linear maps between three dimensional matrix algebras. We also construct two qutrit separable states with lengths ten in the interior of their dual faces. With these examples, we…

Quantum Physics · Physics 2014-01-23 Kil-Chan Ha , Seung-Hyeok Kye

The class of entangled $N$-qubit states known as graph states, and the corresponding stabilizer groups of $N$-qubit Pauli observables, have found a wide range of applications in quantum information processing and the foundations of quantum…

Quantum Physics · Physics 2014-09-26 Mordecai Waegell