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We work out an exactly solvable hamiltonian model which retains all the features of realistic quantum measurements. In order to use an interaction process involving a system and an apparatus as a measurement, it is necessary that the…

Quantum Physics · Physics 2009-11-10 Armen E. Allahverdyan , Roger Balian , Theo M. Nieuwenhuizen

An early approach to include pointers representing measurement devices into quantum mechanics was given by von Neumann. Based on this idea, we model such pointers by qubits and couple them to a free particle, in analogy to a classical…

Quantum Physics · Physics 2021-10-22 Bernd Konrad , Fabio Di Pumpo , Matthias Freyberger

In a fundamental formulation of the quantum mechanics of a closed system such as the universe as a whole, three forms of information are needed to make predictions for the probabilities of alternative time histories of the closed system .…

General Relativity and Quantum Cosmology · Physics 2021-03-16 James B. Hartle

We consider an arbitrary quantum system coupled non perturbatively to a large arbitrary and fully quantum environment. In [G. Ithier and F. Benaych-Georges, Phys. Rev. A 96, 012108 (2017)] the typicality of the dynamics of such an embedded…

Quantum Physics · Physics 2017-12-20 Grégoire Ithier , Saeed Ascroft , Florent Benaych-Georges

Quantum uncertainty relations have deep-rooted significance on the formalism of quantum mechanics. Heisenberg's uncertainty relations attracted a renewed interest for its applications in quantum information science. Robertson derived a…

Quantum Physics · Physics 2023-02-16 Md. Manirul Ali

A type of mechanics will be presented that possesses some distinctive properties. On the one hand, its physical description & rules of operation are readily comprehensible & intuitively clear. On the other, it fully satisfies all observable…

Quantum Physics · Physics 2026-02-05 Eric Tesse

Quantum theory expresses the observable relations between physical properties in terms of probabilities that depend on the specific context described by the "state" of a system. However, the laws of physics that emerge at the macroscopic…

Quantum Physics · Physics 2016-06-06 Holger F. Hofmann

The Hamiltonian of an isolated quantum mechanical system determines its dynamics and physical behaviour. This study investigates the possibility of learning and utilising a system's Hamiltonian and its variational thermal state estimation…

Quantum Physics · Physics 2023-12-22 Jack Y. Araz , Michael Spannowsky

Bohmian mechanics, a hydrodynamic formulation of the quantum theory, constitutes a useful tool to understand the role of the phase as the mechanism responsible for the dynamical evolution displayed by quantum systems. This role is analyzed…

Quantum Physics · Physics 2015-09-30 A. S. Sanz

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

When a closed quantum system is driven periodically with period $T$, it approaches a periodic state synchronized with the drive in which any local observable measured stroboscopically approaches a steady value. For integrable systems, the…

Statistical Mechanics · Physics 2014-08-06 Achilleas Lazarides , Arnab Das , Roderich Moessner

Nonequilibrium states of closed quantum many-body systems defy a thermodynamic description. As a consequence, constraints such as the principle of equal a priori probabilities in the microcanonical ensemble can be relaxed, which can lead to…

Statistical Mechanics · Physics 2019-03-27 Markus Heyl

Classical simulation of quantum systems plays an important role in the study of many-body phenomena and in the benchmarking and verification of quantum technologies. Exact simulation is often limited to small systems because the dimension…

Quantum Physics · Physics 2024-06-04 Dominik S. Wild , Sabina Drăgoi , Corbin McElhanney , Jonathan Wurtz , Sheng-Tao Wang

We investigate the entanglement in the ground state of systems comprising two and three qubits with random interactions. Since the Hamiltonians also contain deterministic one-body terms, by varying the interaction strength, one can…

Quantum Physics · Physics 2023-07-20 Paulo Freitas Gomes , Marcel Novaes , Fernando Parisio

Given a quantum Hamiltonian, we explain how the dynamical properties of the underlying classical system affect the behaviour of quantum eigenstates in the semi-classical limit. We study this problem via the notion of semiclassical measures.…

Mathematical Physics · Physics 2019-05-30 Gabriel Rivière

We propose a (theoretical ;-) model for quantum computation where the result can be read out from the time average of the Hamiltonian dynamics of a 2-dimensional crystal on a cylinder. The Hamiltonian is a spatially local interaction among…

Quantum Physics · Physics 2007-05-23 Dominik Janzing , Pawel Wocjan

Identifying the real and imaginary parts of wave functions with coordinates and momenta, quantum evolution may be mapped onto a classical Hamiltonian system. In addition to the symplectic form, quantum mechanics also has a positive-definite…

Quantum Physics · Physics 2009-11-07 R. Vilela Mendes , V. I. Man'ko

The quantum measurement axiom dictates that physical observables and in particular the Hamiltonian must be diagonalizable and have a real spectrum. For a time-independent Hamiltonian (with a discrete spectrum) these conditions ensure the…

Quantum Physics · Physics 2009-11-13 Ali Mostafazadeh

Coherent states provide a natural connection of quantum systems to their classical limit and are employed in various fields of physics. Here we derive general systematic expansions, with respect to quantum parameters, of expectation values…

Quantum Physics · Physics 2015-08-13 John Schliemann

Assigning the variations of internal energy into heat or work contributions is a challenging task due to the fact that these properties are trajectory dependent. A number of proposals have been put forward for open quantum systems following…

Quantum Physics · Physics 2021-09-01 Adrián Juan-Delgado , Aurélia Chenu