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Related papers: Connecting the quantum and classical worlds

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Although classical mechanics and quantum mechanics are separate disciplines, we live in a world where Planck's constant \hbar>0, meaning that the classical and quantum world views must actually {\it coexist}. Traditionally, canonical…

Quantum Physics · Physics 2015-06-04 John R. Klauder

Quantum mechanics in its presently known formulation requires an external classical time for its description. A classical spacetime manifold and a classical spacetime metric are produced by classical matter fields. In the absence of such…

General Relativity and Quantum Cosmology · Physics 2008-11-26 T. P. Singh

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 provide a Hilbert space approach to quantum mechanics where space and time are treated on an equal footing. Our approach replaces the standard dependence on an external classical time parameter with a spacetime-symmetric algebraic…

Quantum Physics · Physics 2026-02-10 N. L. Diaz , R. Rossignoli

Consistent dynamics which couples classical and quantum degrees of freedom exists, provided it is stochastic. This dynamics is linear in the hybrid state, completely positive and trace preserving. One application of this is to study the…

Quantum Physics · Physics 2023-01-04 Jonathan Oppenheim , Carlo Sparaciari , Barbara Šoda , Zachary Weller-Davies

Assuming that Quantum Mechanics is universal and that it can be applied over all scales, then the Universe is allowed to be in a quantum superposition of states, where each of them can correspond to a different space-time geometry. How can…

General Relativity and Quantum Cosmology · Physics 2024-02-27 José Luis Gaona-Reyes , Lucía Menéndez-Pidal , Mir Faizal , Matteo Carlesso

Quantum physics is a linear theory, so it is somewhat puzzling that it can underlie very complex systems such as digital computers and life. This paper investigates how this is possible. Physically, such complex systems are necessarily…

Quantum Physics · Physics 2024-03-12 George F R Ellis

In physics, experiments ultimately inform us as to what constitutes a good theoretical model of any physical concept: physical space should be no exception. The best picture of physical space in Newtonian physics is given by the…

Quantum Physics · Physics 2017-09-14 Chuan Sheng Chew , Otto C. W. Kong , Jason Payne

Quantum mechanics is nonlocal. Classical mechanics is local. Consequently classical mechanics can not explain all quantum phenomena. Conversely, it is cumbersome to use quantum mechanics to describe classical phenomena. Not only are the…

Quantum Physics · Physics 2007-05-23 Nicolas Gisin , Todd A. Brun , Marco Rigo

Finding a physically consistent approach to modelling interactions between classical and quantum systems is a highly nontrivial task. While many proposals based on various mathematical formalisms have been made, most of these efforts run…

Quantum Physics · Physics 2022-10-05 Marcel Reginatto , Sebastian Ulbricht

An analysis of classical mechanics in a complex extension of phase space shows that a particle in such a space can behave in a way redolant of quantum mechanics; additional degrees of freedom permit 'tunnelling' without recourse to…

Quantum Physics · Physics 2012-02-21 Ray J. Rivers

Quantum systems with a non-conserved probability can be described by means of non-Hermitian Hamiltonians and non-unitary dynamics. In this paper, the case in which the degrees of freedom can be partitioned in two subsets with light and…

Quantum Physics · Physics 2016-10-21 Alessandro Sergi

This paper presents a minimal formulation of nonrelativistic quantum mechanics, by which is meant a formulation which describes the theory in a succinct, self-contained, clear, unambiguous and of course correct manner. The bulk of the…

History and Philosophy of Physics · Physics 2018-04-04 R. Friedberg , P. C. Hohenberg

This paper addresses the question why quantum mechanics is formulated in a unitary Hilbert space, i.e. in a manifestly complex setting. Investigating the linear dynamics of real quantum theory in a finite-dimensional Euclidean Hilbert space…

Quantum Physics · Physics 2019-05-31 Andreas Aste

The physical world is quantum. However, our description of the quantum physics still relies much on concepts in classical physics and in some cases with `quantized' interpretations. The most important case example is that of spacetime. We…

Quantum Physics · Physics 2017-09-13 Otto C. W. Kong

This paper is a review of our recent work on three notorious problems of non-relativistic quantum mechanics: realist interpretation, quantum theory of classical properties and the problem of quantum measurement. A considerable progress has…

Quantum Physics · Physics 2013-03-01 Petr Hajicek

In this work it is shown that there is an inherent nonlinear evolution in the dynamics of the so-called generalized coherent states. To show this, the immersion of a classical manifold into the Hilbert space of quantum mechanics is…

Quantum Physics · Physics 2021-05-05 Hans Cruz-Prado , Giuseppe Marmo , Dieter Schuch , Octavio Castaños

The article explores challenges presented by revelations in physics and the questions they provoke concerning reality. It sheds light on the disparity between the indefinite nature of quantum reality and our perception of classical reality.…

General Physics · Physics 2024-05-14 Jahan N. Schad

In this paper, we demonstrate the equivalence between the complex Hilbert space and real Kahler space formulations of quantum mechanics. Complex numbers play an important role in the traditional formulation of quantum mechanics in complex…

Quantum Physics · Physics 2025-04-24 Igor Volovich

A pedagogical introduction is given to the quantum mechanics of closed systems, most generally the universe as a whole. Quantum mechanics aims at predicting the probabilities of alternative coarse-grained time histories of a closed system.…

General Relativity and Quantum Cosmology · Physics 2014-01-15 James B. Hartle
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