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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

Previous results indicate that while chaos can lead to substantial entropy production, thereby maximizing dynamical entanglement, this still falls short of maximality. Random Matrix Theory (RMT) modeling of composite quantum systems,…

Quantum Physics · Physics 2009-11-07 Jayendra N. Bandyopadhyay , Arul Lakshminarayan

Quantum state tomography is a fundamental tool in quantum information processing. It allows us to estimate the state of a quantum system by measuring different observables on many identically prepared copies of the system. This is, in…

Quantum Physics · Physics 2011-11-28 Carlos A. Riofrío

In a Bell experiment two parties share a quantum state and perform local measurements on their subsystems separately, and the statistics of the measurement outcomes are recorded as a Bell correlation. For any Bell correlation, it turns out…

Quantum Physics · Physics 2017-04-28 Zhaohui Wei , Jamie Sikora

We study entanglement and other correlation properties of random states in high-dimensional bipartite systems. These correlations are quantified by parameters that are subject to the "concentration of measure" phenomenon, meaning that on a…

Quantum Physics · Physics 2007-05-23 Patrick Hayden , Debbie W. Leung , Andreas Winter

We consider quantum entanglement in strongly correlated quantum impurity systems for states manifesting interesting properties such as multi-level Kondo effect and dual nature between itineracy and localization etc.. For this purpose, we…

Strongly Correlated Electrons · Physics 2025-04-03 Yunori Nishikawa , Tomoki Yoshioka

The complexity of quantum many-body systems is manifested in the vast diversity of their correlations, making it challenging to distinguish the generic from the atypical features. This can be addressed by analyzing correlations through…

Quantum Physics · Physics 2023-09-04 Daniel Haag , Flavio Baccari , Georgios Styliaris

Quantum sampling, a fundamental subroutine in numerous quantum algorithms, involves encoding a given probability distribution in the amplitudes of a pure state. Given the hefty cost of large-scale quantum storage, we initiate the study of…

Quantum Physics · Physics 2025-06-10 Longyun Chen , Jingcheng Liu , Penghui Yao

A new interpretation of entanglement entropy is proposed: entanglement entropy of a pure state with respect to a division of a Hilbert space into two subspaces 1 and 2 is an amount of information, which can be transmitted through 1 and 2…

General Relativity and Quantum Cosmology · Physics 2016-08-25 Shinji Mukohyama

We report the experimental measurement of bipartite quantum correlations of an unknown two-qubit state. Using a liquid state Nuclear Magnetic Resonance (NMR) setup and employing geometric discord, we evaluate the quantum correlations of a…

Intrinsic randomness is generated when a quantum state is measured in any basis in which it is not diagonal. In an adversarial scenario, we quantify this randomness by the probability that a correlated eavesdropper could correctly guess the…

Quantum Physics · Physics 2026-02-19 Fionnuala Curran

For a given pure state of a composite quantum system we analyze the product of its projections onto a set of locally orthogonal separable pure states. We derive a bound for this product analogous to the entropic uncertainty relations. For…

Quantum Physics · Physics 2015-05-28 Łukasz Rudnicki , Paweł Horodecki , Karol Życzkowski

We establish three impossibility results regarding our knowledge of the quantum state of the universe. Suppose the universal quantum state is a typical unit vector in a high-dimensional subspace $\mathscr{H}_0$ of Hilbert space…

Quantum Physics · Physics 2026-01-27 Eddy Keming Chen , Roderich Tumulka

The study of conditional $q$-entropies in composite quantum systems has recently been the focus of considerable interest, particularly in connection with the problem of separability. The $q$-entropies depend on the density matrix $\rho$…

Quantum Physics · Physics 2009-11-10 J. Batle , A. R. Plastino , M. Casas , A. Plastino

There is a commonly recognized paradigm in which a multipartite quantum system described by a density matrix having no product eigenbasis is considered to possess nonclassical correlation. Supporting this paradigm, we define two entropic…

Quantum Physics · Physics 2008-05-02 Akira SaiToh , Robabeh Rahimi , Mikio Nakahara

Entanglement is not only the most intriguing feature of quantum mechanics, but also a key resource in quantum information science. The entanglement content of random pure quantum states is almost maximal; such states find applications in…

Quantum Physics · Physics 2009-04-04 Giuliano Benenti

Quantum many-body systems display an extraordinary degree of complexity, yet many of their features are universal: they depend not on microscopic details, but on a few fundamental physical aspects such as symmetries. A central challenge is…

Quantum Physics · Physics 2026-02-02 Jia-Nan Yang , Lata Kh Joshi , Filiberto Ares , Yihang Han , Pengfei Zhang , Pasquale Calabrese

An addition rule of impure density operators, which provides a pure state density operator, is formulated. Quantum interference including visibility property is discussed in the context of the density operator formalism. A measure of…

Quantum Physics · Physics 2009-11-07 Vladimir I Man'ko , Giuseppe Marmo , E C George Sudarshan , Francesco Zaccaria

We demonstrate that the task of determining an unknown quantum state can be accomplished efficiently by making a sequential measurement of two observables $\hat{A}$ and $\hat{B}$, provided that the two observables are chosen in such a way…

Quantum Physics · Physics 2013-10-22 Antonio Di Lorenzo

We characterize the multipartite entanglement of a system of n qubits in terms of the distribution function of the bipartite purity over all balanced bipartitions. We search for those (maximally multipartite entangled) states whose purity…

Quantum Physics · Physics 2010-02-01 Paolo Facchi , Giuseppe Florio , Ugo Marzolino , Giorgio Parisi , Saverio Pascazio