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Related papers: Understanding Quantum Entanglement: Qubits, Rebits…

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We present a description of finite dimensional quantum entanglement, based on a study of the space of all convex decompositions of a given density matrix. On this space we construct a system of real polynomial equations describing separable…

Quantum Physics · Physics 2008-08-27 J. K. Korbicz , F. Hulpke , A. Osterloh , M. Lewenstein

The problem of the relationship between entanglement and two-qubit systems in which it is embedded is central to the quantum information theory. This paper suggests that the concurrence hierarchy as an entanglement measure provides an…

Quantum Physics · Physics 2009-11-11 Mahmoud Abdel-Aty

In this paper, we propose a method to probe entanglement in a theoretically inaccessible quantum system with either a discrete or continuous basis. Our approach leverages insights into the entanglement distribution within a four-partite…

Quantum Physics · Physics 2025-07-10 Pablo C. López Vázquez , Luis M. Piñuelas , Gustavo Montes

Quantum entanglement lies at the heart of quantum mechanics in both fundamental and practical aspects. The entanglement of quantum states has been studied widely, however, the entanglement of operators has not been studied much in spite of…

We present here an overview of our work concerning entanglement properties of composite quantum systems. The characterization of entanglement, i.e. the possibility to assert if a given quantum state is entangled with others and how much…

Quantum Physics · Physics 2007-05-23 K. Eckert , O. Gühne , F. Hulpke , P. Hyllus , J. Korbicz , J. Mompart , D. Bruß , M. Lewenstein , A. Sanpera

One of the essential features of quantum mechanics is that most pairs of observables cannot be measured simultaneously. This phenomenon is most strongly manifested when observables are related to mutually unbiased bases. In this paper, we…

Quantum Physics · Physics 2015-05-27 M. Wiesniak , T. Paterek , A. Zeilinger

The n-qubit real equally weighted states are employed in some quantum algorithms including Deutsch-Jozsa, Grover, Simon, and so on. We qualitatively investigate the entanglement properties of n-qubit real equally weighted states. Firstly,…

Quantum Physics · Physics 2012-07-12 Ri Qu , Yanru Bao

The notion of a qubit is ubiquitous in quantum information processing. In spite of the simple abstract definition of qubits as two-state quantum systems, identifying qubits in physical systems is often unexpectedly difficult. There are an…

Quantum Physics · Physics 2009-11-07 Lorenza Viola , Emanuel Knill , Raymond Laflamme

We explore the role played by the phase in an accurate description of the entanglement of bipartite systems. We first present an appropriate polar decomposition that leads to a truly Hermitian operator for the phase of a single qubit. We…

Quantum Physics · Physics 2007-05-23 Luis L. Sanchez-Soto , Julian Delgado , Andrei B. Klimov , Gunnar Bjork

We study the relationship between the entanglement, mixedness and energy of two-qubit and two-mode Gaussian quantum states. We parametrize the set of allowed states of these two fundamentally different physical systems using measures of…

Quantum Physics · Physics 2009-11-13 Derek McHugh , Mario Ziman , Vladimir Buzek

Various topics concerning the entanglement of composite quantum systems are considered with particular emphasis concerning the strict relations of such a problem with the one of attributing objective properties to the constituents. In…

Quantum Physics · Physics 2009-11-07 GianCarlo Ghirardi , Luca Marinatto

Quantum mechanics dictates the band-structure of materials that is essential for functional electronic components. With increased miniaturization of devices, it becomes possible to exploit the full potential of quantum mechanics through the…

Quantum Physics · Physics 2022-05-26 Kasper Poulsen , Alan C. Santos , Lasse B. Kristensen , Nikolaj T. Zinner

Entanglement lies at the core of quantum algorithms designed to solve problems that are intractable by classical approaches. One such algorithm, quantum annealing (QA), provides a promising path to a practical quantum processor. We have…

These are notes on some entanglement properties of quantum field theory, aiming to make accessible a variety of ideas that are known in the literature. The main goal is to explain how to deal with entanglement when -- as in quantum field…

High Energy Physics - Theory · Physics 2018-10-31 Edward Witten

The quantum mechanics formalism introduced new revolutionary concepts challenging our everyday perceptions. Arguably, quantum entanglement, which explains correlations that cannot be reproduced classically, is the most notable of them.…

We derive two complementarity relations that constrain the individual and bipartite properties that may simultaneously exist in a multi-qubit system. The first expression, valid for an arbitrary pure state of n qubits, demonstrates that the…

Quantum Physics · Physics 2009-11-10 Tracey E. Tessier

Entanglement has long been the subject of discussion by philosophers of quantum theory, and has recently come to play an essential role for physicists in their development of quantum information theory. In this paper we show how the…

Quantum Physics · Physics 2007-05-23 Rob Clifton , Hans Halvorson

The combination of quantum theory and special relativity leads to structures that differ in several respects from non-relativistic quantum mechanics of particles. These differences are quite familiar to practitioners of Algebraic Quantum…

Quantum Physics · Physics 2015-09-02 Jakob Yngvason

We revisit the properties of qubits under Lorentz transformations and, by considering Lorentz invariant quantum states in the Heisenberg formulation, clarify some misleading notation that has appeared in the literature on relativistic…

Quantum Physics · Physics 2017-04-26 Xavier Calmet , Jacob Dunningham

Quantum mechanics is characterized by quantum coherence and entanglement. After having discovered how these fundamental concepts govern physical reality, scientists have been devoting intense efforts to harness them to shape future science…