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A definition of the Schmidt number of a state of an infinite dimensional bipartite quantum system is given and properties of the corresponding family of Schmidt classes are considered. The existence of states with a given Schmidt number…

Quantum Physics · Physics 2013-04-26 M. E. Shirokov

Efficient verification of quantum states and gates is crucial to the development of quantum technologies. Although the sample complexities of quantum state verification and quantum gate verification have been studied by many researchers,…

Quantum Physics · Physics 2021-12-28 Yunting Li , Haoyu Zhang , Zihao Li , Huangjun Zhu

Invariance under local unitary operations is a fundamental property that must be obeyed by every proper measure of quantum entanglement. However, this is not the only aspect of entanglement theory where local unitaries play a relevant role.…

Quantum Physics · Physics 2011-07-05 A. Monras , G. Adesso , S. M. Giampaolo , G. Gualdi , G. B. Davies , F. Illuminati

We consider the question of how large a subspace of a given bipartite quantum system can be when the subspace contains only highly entangled states. This is motivated in part by results of Hayden et al., which show that in large d x…

Quantum Physics · Physics 2017-08-02 T. S. Cubitt , A. Montanaro , A. Winter

Higher dimensional entangled states demonstrate significant advantages in quantum information processing tasks. Schmidt number is a quantity on the entanglement dimension of a bipartite state. Here we build families of k-positive maps from…

Quantum Physics · Physics 2024-03-04 Xian Shi

A set of all states of a bi-partite quantum system can be divided into subsets each of which contains states with the same degree of entanglement. In this paper we address a question whether local operations (without classical…

Quantum Physics · Physics 2007-07-31 Mario Ziman , Vladimir Buzek

We prove that every 2-local automorphism of the unitary group or the general linear group on a complex infinite-dimensional separable Hilbert space is an automorphism. Thus these types of transformations are completely determined by their…

Operator Algebras · Mathematics 2007-05-23 Lajos Molnar , Peter Semrl

We discuss the monotonicity under local operations and classical communication (LOCC) of systematically constructed quantities aiming at quantification of entanglement properties of multipartite quantum systems. The so-called generalized…

Quantum Physics · Physics 2009-11-13 Rafal Demkowicz-Dobrzanski , Andreas Buchleitner , Marek Kus , Florian Mintert

We investigate how originally localized two pieces of quantum information represented by a tensor product of two unknown qudit states are delocalized by performing two-qudit global unitary operations. To characterize the delocalization…

Quantum Physics · Physics 2010-09-15 Akihito Soeda , Mio Murao

The general class of Gaussian Schmidt-number witness operators for bipartite systems is studied. It is shown that any member of this class is reducible to a convex combination of two types of Gaussian operators using local operations and…

Quantum Physics · Physics 2013-12-31 Farid Shahandeh , Jan Sperling , Werner Vogel

We introduce two operational entanglement measures which are applicable for arbitrary multipartite (pure or mixed) states. One of them characterizes the potentiality of a state to generate other states via local operations assisted by…

Quantum Physics · Physics 2015-10-14 K. Schwaiger , D. Sauerwein , M. Cuquet , J. I. de Vicente , B. Kraus

Nielsen characterized in full those 2-party quantum protocols of local operations and classical communication that transform, with probability one, a pure global initial state into a pure global final state. The present work considers the…

Quantum Physics · Physics 2012-02-16 Daniel Lehmann

Entanglement is an useful resource because some global operations cannot be locally implemented using classical communication. We prove a number of results about what is and is not locally possible. We focus on orthogonal states, which can…

Quantum Physics · Physics 2009-11-07 Jonathan Walgate , Lucien Hardy

By exploiting the permutation symmetry of Dick states, we derive closed analytical expressions of Schmidt decompositions for {\it all} possible bipartitions of a system described by this kind of state. This allows us to exhaustively compute…

Quantum Physics · Physics 2018-01-03 M. G. M. Moreno , Fernando Parisio

We conjecture analytic expressions for the non-local magic of bipartite pure qudit states of prime local dimension. Our construction relies on the Schmidt-aligned state attaining the minimum over local unitaries, a hypothesis that we…

Quantum Physics · Physics 2026-03-11 Giorgio Busoni , John Gargalionis , Ewan N. V. Wallace , Martin J. White

Some progress is reported on conditions for convertibility among bipartite 2x2 entangled states: An inconvertibility condition related to the rank of an entangled state is given that it is impossible to convert to an entangled state with…

Quantum Physics · Physics 2024-02-14 Yiruo Lin

Entanglement distillation is a key task in quantum-information processing. In this paper, we distill non-positive-partial-transpose (NPT) bipartite states of some given Schmidt rank and matrix rank. We show that all bipartite states of…

Quantum Physics · Physics 2023-07-07 Tianyi Ding , Lin Chen

We examine bipartite and multipartite correlations within the construct of unitary orbits. We show that the set of product states is a very small subset of set of all possible states, while all unitary orbits contain classically correlated…

Quantum Physics · Physics 2015-02-11 Kavan Modi , Mile Gu

We study Schmidt rank for a vector (i.e., a pure state) and Schmidt number for a mixed state which are entanglement measures. We show that if a subspace of a certain bipartite system contains no vector of Schmidt rank $\leqslant k$, then…

Quantum Physics · Physics 2018-04-13 Priyabrata Bag , Santanu Dey

We consider the question of perfect local distinguishability of mutually orthogonal bipartite quantum states, with the property that every state can be specified by a unitary operator acting on the local Hilbert space of Bob. We show that…

Quantum Physics · Physics 2015-05-27 Somshubhro Bandyopadhyay , Sibasish Ghosh , Guruprasad Kar