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The existence of incompatible measurements, i.e. measurements which cannot be performed simultaneously on a single copy of a quantum state, constitutes an important distinction between quantum mechanics and classical theories. While…

Quantum Physics · Physics 2022-06-22 Krzysztof Mordasewicz , Jędrzej Kaniewski

A common feature of the extended phase space of gauge theory, the crossed product of quantum theory, and quantum reference frames (QRFs) is the adjoining of degrees of freedom followed by a constraining procedure for the resulting total…

High Energy Physics - Theory · Physics 2024-10-16 Shadi Ali Ahmad , Wissam Chemissany , Marc S. Klinger , Robert G. Leigh

A global measure of quantum correlations for tripartite nonorthogonal states is presented. It is introduced as the overall average of the pairwise correlations existing in all possible partitions. The explicit expressions for the global…

Quantum Physics · Physics 2014-12-02 M. Daoud , R. Ahl Laamara , R. Essaber , W. Kaydi

In recent years, quantum phase transitions have attracted the interest of both theorists and experimentalists in condensed matter physics. These transitions, which are accessed at zero temperature by variation of a non-thermal control…

Condensed Matter · Physics 2009-11-10 Matthias Vojta

Experimentally, the imaginary parts of complex weak values are obtained from the response of the system to small unitary phase shifts generated by the target observable. The complex conditional probabilities obtained from weak measurements…

Quantum Physics · Physics 2011-05-03 Holger F. Hofmann

We show that, for $N$ parallel input states, an anti-linear map with respect to a specific basis is essentially a classical operator. We also consider the information contained in phase-conjugate pairs $|\phi > |\phi^*>$, and prove that…

Quantum Physics · Physics 2009-11-13 Xiang-Fa Zhou , Yong-Sheng Zhang , Guang-Can Guo

I present a selective survey of the phases of quantum matter with varieties of many-particle quantum entanglement. I classify the phases as gapped, conformal, or compressible quantum matter. Gapped quantum matter is illustrated by a simple…

High Energy Physics - Theory · Physics 2012-05-23 Subir Sachdev

We investigate the correlation properties of separable two qubit states with maximally mixed marginals. These states are divided to two sets with the same geometric quantum correlation. However a closer scrutiny of these states reveals a…

Quantum Physics · Physics 2015-01-14 Azam Mani , Vahid Karimipour , Laleh Memarzadeh

We investigate quantum walks in multiple dimensions with different quantum coins. We augment the model by assuming that at each step the amplitudes of the coin state are multiplied by random phases. This model enables us to study in detail…

Quantum Physics · Physics 2009-11-13 Jozef Kosik , Vladimir Buzek , Mark Hillery

Wave-particle duality as one of the expression of Bohr complementarity is a significant concept in the field of quantum mechanics. Quantitative analysis of wave-particle duality aims to establish a complementary relation between the…

Quantum Physics · Physics 2025-05-08 Zhaofang Bai , ShuanpingDu

We formulate a relation between quantum-mechanical coherent states and complex-differentiable structures on the classical phase space ${\cal C}$ of a finite number of degrees of freedom. Locally-defined coherent states parametrised by the…

Quantum Physics · Physics 2015-06-26 J. M. Isidro

We describe a general framework to study covariant symmetric broadcasting maps for mixed qubit states. We explicitly derive the optimal N to M superbroadcasting maps, achieving optimal purification of the single-site output copy, in both…

Quantum Physics · Physics 2007-05-23 Francesco Buscemi , Giacomo Mauro D'Ariano , Chiara Macchiavello , Paolo Perinotti

We introduce new families of pure quantum states that are constructed on top of the well-known Gilmore-Perelomov group-theoretic coherent states. We do this by constructing unitaries as the exponential of operators quadratic in Cartan…

Quantum Physics · Physics 2021-05-12 Tommaso Guaita , Lucas Hackl , Tao Shi , Eugene Demler , J. Ignacio Cirac

The notion of "paired" fermions is central to important condensed matter phenomena such as superconductivity and superfluidity. While the concept is widely used and its physical meaning is clear there exists no systematic and mathematical…

Quantum Physics · Physics 2009-11-13 Christina V. Kraus , Michael M. Wolf , J. Ignacio Cirac , Geza Giedke

We obtain a representation of pairing energies in phase space, for the Lipkin-Meshkov-Glick and general boson Bardeen-Cooper-Schrieffer pairing models. This is done by means of a probability distribution of the quantum state in phase space.…

Quantum Physics · Physics 2014-11-14 M. Calixto , O. Castaños , E. Romera

Quantum coherence is an exquisitely quantum phenomenon that depends on both probability amplitudes and relative phases. Standard coherence measures quantify superposition within density matrices but cannot distinguish ensembles that produce…

Quantum Physics · Physics 2026-05-29 Cameron Hahn , Nishan Ranabhat , Fabio Anza

The dynamics at the critical-point of a general first-order quantum phase transition in a finite system is examined, from an algebraic perspective. Suitable Hamiltonians are constructed whose spectra exhibit coexistence of states…

Nuclear Theory · Physics 2014-11-18 A. Leviatan

Quantum reference frame transformations have been proposed to provide a means by which to translate descriptions of quantum systems relative to each other. At present, there are several differing frameworks for describing quantum reference…

Quantum Physics · Physics 2025-09-29 Esteban Castro-Ruiz , Thomas D. Galley , Leon Loveridge

We use coherent states as trial states for a variational approach to study a system of a finite number of three-level atoms interacting in a dipolar approximation with a one-mode electromagnetic field. The atoms are treated as…

Quantum Physics · Physics 2018-06-20 L. F. Quezada , E. Nahmad-Achar

Transition amplitudes and transition probabilities are relevant to many areas of physics simulation, including the calculation of response properties and correlation functions. These quantities can also be related to solving linear systems…

Quantum Physics · Physics 2023-09-18 Nicolas PD Sawaya , Joonsuk Huh