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The hilbert-space structure of quantum mechanics is related to the causal structure of space-time. The usual measurement hypotheses apparently preclude nonlinear or stochastic quantum evolution. By admitting a difference in the calculus of…

Quantum Physics · Physics 2007-05-23 George Svetlichny

Time evolution is an indivisible part in any physics theory. Usually, people are accustomed to think that the universe is a fixed background and the system itself evolves step by step in time. However, Yakir Aharonov challenges this view…

Quantum Physics · Physics 2019-08-09 Hai Wang , Ray-Kuang Lee , Junde Wu

Probability theory can be modified in essentially one way while maintaining consistency with the basic Bayesian framework. This modification results in copies of standard probability theory for real, complex or quaternion probabilities.…

High Energy Physics - Theory · Physics 2007-05-23 Saul Youssef

We analyze the problem of one dimensional quantum particle falling in a constant gravitational field, also known as the {\it bouncing ball}, employing a semiclassical approach known as momentous effective quantum mechanics. In this…

Quantum Physics · Physics 2019-04-16 Guillermo Chacon-Acosta , Hector Hernandez-Hernandez , Mercedes Velazquez

We study classical Hamiltonian systems in which the intrinsic proper time evolution parameter is related through a probability distribution to the physical time, which is assumed to be discrete. In this way, a physical clock with discrete…

Quantum Physics · Physics 2007-05-23 H. -T. Elze

In this paper we study a class of physical systems that combine a finite number of mechanical and thermodynamic observables. We call them finite dimensional thermo-mechanical systems. We introduce these systems by means of simple examples.…

Mathematical Physics · Physics 2016-09-29 Hernán Cendra , Sergio Grillo , Maximiliano Palacios Amaya

It is considered constraints imposed by the quantum mechanics on the measurement of the density of the electromagnetic energy. First, the energy of the electromagnetic wave and the volume (time) are bound with the Heisenberg uncertainty…

General Physics · Physics 2007-05-23 D. L. Khokhlov

This letter serves as the generalization of the work 2505.16436, where we investigated the quantum field theory in Klein space which has two time directions. We extend studies to the general spacetime $\mathbb{R}^{n,d-n}\,(n,d-n\geq2)$ in a…

High Energy Physics - Theory · Physics 2025-10-21 Bin Chen , Zezhou Hu , Xin-Cheng Mao

When the proper time of general relativity is adjusted to reflect the possible existence of higher dimensions, small dynamical effects appear in spacetime of the sort usually associated with the cosmological constant, Hubble's Law and…

General Physics · Physics 2010-11-15 Paul S. Wesson

In this article, the axioms presented in the first one are reformulated according to the special theory of relativity. Using these axioms, quantum mechanic's relativistic equations are obtained in the presence of electromagnetic fields for…

Quantum Physics · Physics 2008-02-03 L. S. F. Olavo

A long-standing problem in quantum gravity and cosmology is the quantization of systems in which time evolution is generated by a constraint that must vanish on solutions. Here, an algebraic formulation of this problem is presented,…

Mathematical Physics · Physics 2021-03-19 Martin Bojowald , Artur Tsobanjan

Beginning with the principle that a closed mechanical composite system is timeless, time can be defined by the regular changes in a suitable position coordinate (clock) in the observing part, when one part of the closed composite observes…

Quantum Physics · Physics 2021-10-05 John S. Briggs

Attempts to consider evolution across space-time singularities often lead to quantum systems with time-dependent Hamiltonians developing an isolated singularity as a function of time. Examples include matrix theory in certain singular…

High Energy Physics - Theory · Physics 2009-04-17 Ben Craps , Oleg Evnin

The time-dependent variational principle using generalized Gaussian trial functions yields a finite dimensional approximation to the full quantum dynamics and is used in many disciplines. It is shown how these 'semi-quantum' dynamics may be…

chao-dyn · Physics 2009-10-22 Arjendu K. Pattanayak , William C. Schieve

A formalism is developed for describing approximate classical behaviour in finite (but possibly large) quantum systems. This is done in terms of a structure common to classical and quantum mechanics, viz. a Poisson space with a transition…

Quantum Physics · Physics 2015-06-26 N. P. Landsman

The evolution of both quantum and classical ensembles may be described via the probability density P on configuration space, its canonical conjugate S, and an_ensemble_ Hamiltonian H[P,S]. For quantum ensembles this evolution is, of course,…

Quantum Physics · Physics 2009-11-10 Michael J. W. Hall

We formulate a simple extension of general relativity which incorporates space-time variations in the Newtonian gravitation 'constant', $G$, and the fine structure 'constant', $\alpha $, which generalises Brans-Dicke theory and our theory…

Astrophysics · Physics 2014-10-13 J. D. Barrow , J. Magueijo , H. B. Sandvik

We quantize the Helmholtz equation (plus perturbative interactions) in two dimensions to illustrate a manifestly local description of quantum field theory. Using the general boundary formulation we describe the quantum dynamics both in a…

High Energy Physics - Theory · Physics 2009-06-25 Daniele Colosi , Robert Oeckl

Fluctuation terms and higher moments of a quantum state imply corrections to the classical equations of motion that may have implications in early-universe cosmology, for instance in the state-dependent form of effective potentials. In…

General Relativity and Quantum Cosmology · Physics 2023-07-10 Martin Bojowald , Freddy Hancock

We propose a solution to the problem of time for systems with a single global Hamiltonian constraint. Our solution stems from the observation that, for these theories, conventional gauge theory methods fail to capture the full classical…

General Relativity and Quantum Cosmology · Physics 2015-05-30 Sean Gryb , Karim Thebault