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In Quantum Mechanics operators must be hermitian and, in a direct product space, symmetric. These properties are saved by Lie algebra operators but not by those of quantum algebras. A possible correspondence between observables and quantum…

High Energy Physics - Theory · Physics 2009-11-07 E. Celeghini , M. A. del Olmo

A time operator is a Hermitian operator that is canonically conjugate to a given Hamiltonian. For a particle in 1-dimension, a Hamiltonian conjugate operator in position representation can be obtained by solving a hyperbolic second-order…

Quantum Physics · Physics 2024-09-06 Ralph Adrian E. Farrales , Herbert B. Domingo , Eric A. Galapon

An apparent paradox is resolved that concerns the existence of time operators which have been derived for the quantum harmonic oscillator. There is an apparent paradox because, although a time operator is canonically conjugate to the…

Quantum Physics · Physics 2007-05-23 Alex Granik , H. Ralph Lewis

It is shown that in presence of certain external fields a well defined self-adjoint time operator exists, satisfying the standard canonical commutation relations with the Hamiltonian. Examples include uniform electric and gravitational…

Quantum Physics · Physics 2023-12-15 A. M. Schlichtinger , A. Jadczyk

Canonical variables for the Poisson algebra of quantum moments are introduced here, expressing semiclassical quantum mechanics as a canonical dynamical system that extends the classical phase space. New realizations for up to fourth order…

Quantum Physics · Physics 2019-05-01 Bekir Baytas , Martin Bojowald , Sean Crowe

Classical transport equations with probabilistic initial conditions can be viewed as quantum systems. In a discrete version they are probabilistic automata. The time-local probabilistic information is encoded in a classical wave function.…

Quantum Physics · Physics 2026-05-18 Christof Wetterich

It is shown that, under the Wentzel-Kramers-Brillouin approximation conditions, using the Foldy-Wouthuysen representation allows the problem of finding a classical limit of relativistic quantum mechanical equations to be reduced to the…

Mathematical Physics · Physics 2013-02-11 A. J. Silenko

We define a new quantum Hermitian operator (namely, the energy variance operator) which is simply duplicated from the statistical definition of energy variance in classical physics. Its expectation value yields the standard deviation of the…

Quantum Physics · Physics 2022-05-26 Gilbert Reinisch

During the recent developments of quantum theory it has been clarified that the observable quantities (like energy or position) may be represented by operators (with real spectra) which are manifestly non-Hermitian. The mathematical…

Geometric (Schrodinger) quantization of nonrelativistic mechanics with respect to different reference frames is considered. In classical nonrelativistic mechanics, a reference frame is represented by a connection on a configuration space…

Quantum Physics · Physics 2009-11-13 L. Mangiarotti , G. Sardanashvily

Any account of the emergence of classicality from quantum theory must address the fact that the quantum operators representing positions and momenta do not commute, whereas their classical counterparts suffer no such restrictions. To…

Quantum Physics · Physics 2015-05-13 J. J. Halliwell

The classical time of arrival in the interacting case is quantized by way of quantizing its expansion about the free time of arrival. The quantization is formulated in coordinate representation which represents ordering rules in terms of…

Quantum Physics · Physics 2019-04-24 Eric A. Galapon , John Jaykel P. Magadan

Non-relativistic quantum mechanics is shown to emerge from classical mechanics through the requirement of a relativity principle based on special transformations acting on position and momentum uncertainties. These transformations keep the…

Quantum Physics · Physics 2007-05-23 Léon Brenig

A Hermitian quantum phase operator is formulated that mirrors the classical phase variable with proper time dependence and satisfies trigonometric identities. The eigenstates of the phase operator are solved in terms of Gegenbauer…

Quantum Physics · Physics 2016-04-26 Xin Ma , William Rhodes

Based on a number of experimentally verified physical observations, it is argued that the standard principles of quantum mechanics should be applied to the Universe as a whole. Thus, a paradigm is proposed in which the entire Universe is…

General Relativity and Quantum Cosmology · Physics 2007-05-23 J. S. Eakins

Examples are given of non-Hermitian Hamiltonian operators which have a real spectrum. Some of the investigated operators are expressed in terms of the generators of the Weil-Heisenberg algebra. It is argued that the existence of an…

Quantum Physics · Physics 2009-09-29 João da Providência , Natália Bebiano , João Pinheiro da Providência

In principle, non-Hermitian quantum equations of motion can be formulated using as a starting point either the Heisenberg's or the Schr\"odinger's picture of quantum dynamics. Here it is shown in both cases how to map the algebra of…

Quantum Physics · Physics 2011-02-07 Alessandro Sergi

Simulating physical systems has been an important application of classical and quantum computers. In this article we present an efficient classical algorithm for simulating time-dependent quantum mechanical Hamiltonians over constant…

Quantum Physics · Physics 2023-01-30 Reyhaneh Aghaei Saem , Ali Hamed Moosavian

The generalized h-dependent operator algebra is defined ($0\leq h \leq h_o$). For h= h_o it becomes equivalent to the quantum mechanical algebra of observables and for h=0 it is equivalent to the classical one. We show this by proposing how…

Quantum Physics · Physics 2007-05-23 S. Prvanovic , Z. Maric , Belgrade , Serbia

We study the problem of computing the probability for the time-of-arrival of a quantum particle at a given spatial position. We consider a solution to this problem based on the spectral decomposition of the particle's (Heisenberg) state…

Quantum Physics · Physics 2009-10-30 Norbert Grot , Carlo Rovelli , Ranjeet S. Tate