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We consider the separability of various joint states of D-dimensional quantum systems, which we call "qudits." We derive two main results: (i) the separability condition for a two-qudit state that is a mixture of the maximally mixed state…

Quantum Physics · Physics 2012-01-04 P. Rungta , W. J. Munro , K. Nemoto , P. Deuar , G. J. Milburn , C. M. Caves

The complete reducibility property for bipartite states reduced the separability problem to a proper subset of positive under partial transpose states and was used to prove several theorems inside and outside entanglement theory. So far…

Quantum Physics · Physics 2025-09-10 Daniel Cariello

We prove a theorem for coding mixed-state quantum signals. For a class of coding schemes, the von Neumann entropy $S$ of the density operator describing an ensemble of mixed quantum signal states is shown to be equal to the number of…

Quantum Physics · Physics 2015-06-26 Hoi-Kwong Lo

We derive inequalities for $n$ spin-1/2 systems under the assumption that the hidden-variable theoretical joint probability distribution for any pair of commuting observables is equal to the quantum mechanical one. Fine showed that this…

Quantum Physics · Physics 2015-06-26 Koji Nagata

One of the most important questions in quantum information theory is the so-called separability problem. It involves characterizing the set of separable (or, equivalently entangled) states among mixed states of a multipartite quantum…

Quantum Physics · Physics 2014-12-16 Michał Oszmaniec

We study two-state discrimination in chaotic quantum systems. Assuming that one of two $N$-qubit pure states has been randomly selected, the probability to correctly identify the selected state from an optimally chosen experiment involving…

Quantum Physics · Physics 2023-05-30 Joaquim Telles de Miranda , Tobias Micklitz

Both classical and quantum mechanics assume that physical laws are invariant under changes in the way that the world is labeled. This Principle of Decompositional Equivalence is formalized, and shown to forbid finite experimental…

Quantum Physics · Physics 2010-04-22 Chris Fields

A bipartite quantum state (for two systems in any dimensions) can be decomposed as a superposition of many components. For a superposition of more than two components we prove that there is a bound of the entanglement of the superposition…

Quantum Physics · Physics 2009-11-13 Yang Xiang , Shi-Jie Xiong , Fang-Yu Hong

In this work, we present new connections between three types of quantum states: positive under partial transpose states, symmetric with positive coefficients states and invariant under realignment states. First, we obtain a common upper…

Quantum Physics · Physics 2025-02-11 Daniel Cariello

Quantum theory of the free Maxwell field in Minkowski space is constructed using a representation in which the self dual connection is diagonal. Quantum states are now holomorphic functionals of self dual connections and a decomposition of…

High Energy Physics - Theory · Physics 2010-11-01 Abhay Ashtekar , Carlo Rovelli , Lee Smolin

The Schmidt number represents the genuine entanglement dimension of a bipartite quantum state. We derive simple criteria for the Schmidt number of a density matrix in arbitrary local dimensions. They are based on the trace norm of…

Quantum Physics · Physics 2024-12-18 Armin Tavakoli , Simon Morelli

Recently, it has been argued that quantum mechanics is a complete theory, and that different quantum states do necessarily correspond to different elements of reality, under the assumptions that quantum mechanics is correct and that…

Quantum Physics · Physics 2015-06-23 Giancarlo Ghirardi , Raffaele Romano

The CQC conjecture by Schneeloch et al. (Physical Review A 90.6, 2014) asserts that the sum of classical mutual information between two parties obtained by measuring individual systems in two mutually unbiased bases cannot exceed their…

Quantum Physics · Physics 2026-05-26 Hasan Iqbal

It is shown how it is possible to reconstruct the initial state of a one-dimensional system by measuring sequentially two conjugate variables. The procedure relies on the quasi-characteristic function, the Fourier-transform of the Wigner…

Quantum Physics · Physics 2013-01-07 Antonio Di Lorenzo

Entanglement of any pure state of an N times N bi-partite quantum system may be characterized by the vector of coefficients arising by its Schmidt decomposition. We analyze various measures of entanglement derived from the generalized…

Quantum Physics · Physics 2009-11-07 Karol Zyczkowski , Ingemar Bengtsson

We consider the classical correlations that two observers can extract by measurements on a bipartite quantum state, and we discuss how they are related to the quantum mutual information of the state. We show with several examples how…

Quantum Physics · Physics 2009-09-19 Shengjun Wu , Uffe V. Poulsen , Klaus Mølmer

We generalise the concept of duality to systems of ordinary difference equations (or maps). We propose a procedure to construct a chain of systems of equations which are dual, with respect to an integral $H$, to the given system, by…

Exactly Solvable and Integrable Systems · Physics 2020-01-08 J. M. Tuwankotta , P. H. van der Kamp , G. R. W. Quispel , K. V. I. Saputra

In generalized resource theories, one aims to reformulate the problem of deciding whether a suitable transition (typically a transition that preserves the Gibbs state of the theory) between two given states $\rho$ and $\sigma$ exists or…

Quantum Physics · Physics 2015-05-05 Francesco Buscemi

Traditionally, quantum state correlation can be obtained with calculations on a state density matrix already known. Here, we propose a model with which correlations of unknown quantum states can be obtained. There are no needs of classical…

Quantum Physics · Physics 2018-06-18 Hui Li , Yan-Song Li , Chao Zheng , Xian Lu

We characterize and classify quantum correlations in two-fermion systems having 2K single-particle states. For pure states we introduce the Slater decomposition and rank (in analogy to Schmidt decomposition and rank), i.e. we decompose the…

Quantum Physics · Physics 2009-11-06 John Schliemann , J. Ignacio Cirac , Marek Kus , Maciej Lewenstein , Daniel Loss