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In classical theory, the physical systems are elucidated through the concepts of particles and waves, which aim to describe the reality of the physical system with certainty. In this framework, particles are mathematically represented by…

Quantum Physics · Physics 2024-09-25 Mohammad Vahid Takook , Ali Mohammad-Djafari

While all bipartite pure entangled states violate some Bell inequality, the relationship between entanglement and non-locality for mixed quantum states is not well understood. We introduce a simple and efficient algorithmic approach for the…

Quantum Physics · Physics 2009-11-07 Barbara M. Terhal , Andrew C. Doherty , David Schwab

We characterize the multipartite entanglement of a system of n qubits in terms of the distribution function of the bipartite purity over balanced bipartitions. We search for maximally multipartite entangled states, whose average purity is…

Quantum Physics · Physics 2015-03-13 P. Facchi , G. Florio , U. Marzolino , G. Parisi , S. Pascazio

Recently, it has been argued that quantum mechanics is complete, and that quantum states vectors are necessarily in one-to-one correspondence with the elements of reality, under the assumptions that quantum theory is correct and that…

Quantum Physics · Physics 2013-06-24 GianCarlo Ghirardi , Raffaele Romano

The quantum teleportation protocol can be used to probabilistically simulate a quantum circuit with backward-in-time connections. This allows us to analyze some conceptual problems of time travel in the context of physically realizable…

Quantum Physics · Physics 2012-03-06 George Svetlichny

The traditional formalism of non-relativistic quantum theory allows the state of a quantum system to extend across space, but only restricts it to a single instant in time, leading to distinction between theoretical treatments of spatial…

Quantum Physics · Physics 2018-11-21 Zhikuan Zhao , Robert Pisarczyk , Jayne Thompson , Mile Gu , Vlatko Vedral , Joseph F. Fitzsimons

The conceptual setting of quantum mechanics is subject to an ongoing debate from its beginnings until now. The consequences of the apparent differences between quantum statistics and classical statistics range from the philosophical…

Quantum Physics · Physics 2015-05-13 C. Wetterich

Given a quantum system on many qubits split into a few different parties, how many total correlations are there between these parties? Such a quantity, aimed to measure the deviation of the global quantum state from an uncorrelated state…

Quantum Physics · Physics 2022-02-15 Zhenhuan Liu , Pei Zeng , You Zhou , Mile Gu

We settle the so-called degree conjecture for the separability of multipartite quantum states, which are normalized graph Laplacians, first given by Braunstein {\it et al.} [Phys. Rev. A \textbf{73}, 012320 (2006)]. The conjecture states…

Quantum Physics · Physics 2009-11-13 Ali Saif M. Hassan , Pramod Joag

This paper introduces quantum multiparty protocols which allow the use of temporary assumptions. We prove that secure quantum multiparty computations are possible if and only if classical multi party computations work. But these strict…

Quantum Physics · Physics 2007-05-23 J. Mueller-Quade , H. Imai

While experimental advancements continue to expand the capabilities to control and probe non-equilibrium quantum matter at an unprecedented level, the numerical simulation of the dynamics of correlated quantum systems remains a pivotal…

Quantum Physics · Physics 2025-06-04 Markus Schmitt , Markus Heyl

We study the construction of both universal quantum computation and multi-partite entangled states in the topological diagrammatical approach to quantum teleportation. Our results show that the teleportation-based quantum circuit model…

Quantum Physics · Physics 2013-10-11 Yong Zhang , Jinglong Pang

First, we show how the quantum circuits for generating and measuring multi-party entanglement of qubits can be translated to continuous quantum variables. We derive sufficient inseparability criteria for $N$-party continuous-variable states…

Quantum Physics · Physics 2007-05-23 Peter van Loock , Samuel L. Braunstein

Closed bipartite quantum systems subject to fast local unitary control are studied using quantum optimal control theory and a method of reduced control systems based on the Schmidt decomposition. Particular focus is given to the…

Quantum Physics · Physics 2024-05-31 Emanuel Malvetti , Léo Van Damme

Due to the absence of an external, classical time variable, the probabilistic predictions of covariant quantum theory are ambiguous when multiple measurements are considered. Here, we introduce an information theoretic framework to the…

Quantum Physics · Physics 2011-11-09 S. Jay Olson , Jonathan P. Dowling

In the quantum theory, it has been shown that one can see if a process has the time reversal symmetry by applying the matrix transposition and examining if it remains physical. However, recent discoveries regarding the indefinite causal…

Quantum Physics · Physics 2023-06-29 Seok Hyung Lie , M. S. Kim

We formulate quantum mechanics as an effective theory of an underlying structure characterized by microstates $|{\mathcal M}^j(t)\rangle$, each one defined by the quantum state $|\Psi(t)\rangle$ and a complete set of commutative observables…

Quantum Physics · Physics 2017-10-30 Marco Matone

This thesis focuses on three main questions in the continuous variable and optical settings: where does a quantum advantage, that is, the ability of quantum machines to outperform classical machines, come from? How to ensure the proper…

Quantum Physics · Physics 2021-02-11 Ulysse Chabaud

In the usual tomography of multipartite entangled quantum states one assumes that the measurement devices used in the laboratory are under perfect control of the experimenter. In this paper, using the so-called SWAP concept introduced…

Quantum Physics · Physics 2014-11-05 Karoly F. Pal , Tamas Vertesi , Miguel Navascues

We pursue the view that quantum theory may be an emergent structure related to large space-time scales. In particular, we consider classical Hamiltonian systems in which the intrinsic proper time evolution parameter is related through a…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Hans-Thomas Elze