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It is well known that the time dependent harmonic oscillator possesses a conserved quantity, usually called Ermakov-Lewis invariant. I provide a simple physical interpretation of this invariant as well as a whole family of related…

Classical Physics · Physics 2018-04-04 T. Padmanabhan

It is argued by Duff that only the time variation of dimensionless constants of nature is a legitimate subject of enquiry, and that dimensional constants such as c, h-bar and G... are merely human constructs whose value has no operational…

High Energy Physics - Theory · Physics 2007-05-23 J. W. Moffat

We show how expansions in powers of Planck's constant hbar = h/2\pi can give new insights into perturbative and nonperturbative properties of quantum field theories. Since hbar is a fundamental parameter, exact Lorentz invariance and gauge…

High Energy Physics - Phenomenology · Physics 2011-03-23 Stanley J. Brodsky , Paul Hoyer

The quantization of a constant of motion for the harmonic oscillator with a time-explicitly depending external force is carried out. This quantization approach is compared with the normal Hamiltonian quantization approach. Numerical results…

Quantum Physics · Physics 2016-09-08 G. Lopez

The possibility is discussed of inferring or simulating some aspects of quantum dynamics by adding classical statistical fluctuations to classical mechanics. We introduce a general principle of mechanical stability and derive a necessary…

Quantum Physics · Physics 2015-06-26 Salvatore De Martino , Silvio De Siena , Fabrizio Illuminati

Time variation of Newtonian gravitational constant, $G$, is studied in the model universe with variable space dimension proposed recently. Using the Lagrangian formulation of these models, we find the effective gravitational constant as a…

General Relativity and Quantum Cosmology · Physics 2011-08-17 R. Mansouri , F. Nasseri , M. Khorrami

The Heisenberg uncertainty principle is one of the fundamental pillars of quantum mechanics and quantum field theory. It is normally introduced by postulating the commutation relations $[\hat{x}^i, \hat{p}^j] = i\hbar \delta^{ij}$. However,…

High Energy Physics - Phenomenology · Physics 2026-01-29 Ezequiel Valero , Hector Gisbert , Victor Ilisie

We begin by discussing known theoretical results about the sensitivity of quantum states to changes in the value of Planck's constant h. These questions are related to positivity issues for self-adjoint trace class operators, which are not…

Quantum Physics · Physics 2016-12-19 Maurice de Gosson , Makan Mohageg

As we showed in a preceding arXiv:gr-qc Einstein equations, conveniently written, provide the more orthodox and simple description of cosmological models with a time dependent speed of light $c$. We derive here the concomitant dependence of…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Ll. Bel

We show that promoting the trace part of the Einstein equations to a trivial identity results in the Newton constant being an integration constant. Thus, in this formulation the Newton constant is a global dynamical degree of freedom which…

General Relativity and Quantum Cosmology · Physics 2021-04-16 Pavel Jiroušek , Keigo Shimada , Alexander Vikman , Masahide Yamaguchi

Quantum dynamics of a Dirac particle in a 1D box with moving wall is studied. Dirac equation with time-dependent boundary condition is mapped onto that with static one, but with time-dependent mass. Exact analytical solution of such…

Quantum Physics · Physics 2024-06-20 J. Dittrich , S. Rakhmanov , D. Matrasulov

Segal proposed ultraquantum commutation relations with two ultraquantum constants hbar' and hbar'' besides Planck's quantum constant hbar with a variable i. The Heisenberg quantum algebra is a contraction - in a more general sense than that…

High Energy Physics - Theory · Physics 2014-11-18 James Baugh , David Ritz Finkelstein , Andrei Galiautdinov , Mohsen Shiri-Garakani

In unimodular-like theories, the constants of nature are demoted from pre-given parameters to phase space variables. Their canonical duals provide physical time variables. We investigate how this interacts with an alternative approach to…

High Energy Physics - Theory · Physics 2023-12-12 Paolo M Bassani , Joao Magueijo

The effect of fractal space time of the quantum particles on the variation of the fine structure constant $\alpha$ has been studied. The variation of fine structure constant has been investigated around De Broglie length $\lambda$ and…

Cosmology and Nongalactic Astrophysics · Physics 2013-09-05 A. Bhattacharya , A. Chandra , B. Chakrabarti

If the fine structure constant $\alpha =e^2/(\hbar c)$ were to change, then a number of interpretations would be possible, attributing this change either to variations in the electron charge, the dielectric constant of the vacuum, the speed…

Astrophysics · Physics 2009-10-31 John D. Barrow , Joao Magueijo

We propose uncertainty relations for the different coordinates of spacetime events, motivated by Heisenberg's principle and by Einstein's theory of classical gravity. A model of Quantum Spacetime is then discussed where the commutation…

High Energy Physics - Theory · Physics 2015-06-26 Sergio Doplicher , Klaus Fredenhagen , John E. Roberts

The Heisenberg uncertainty principle states that the product of the noise in a position measurement and the momentum disturbance caused by that measurement should be no less than the limit set by Planck's constant, hbar/2, as demonstrated…

Quantum Physics · Physics 2009-11-07 Masanao Ozawa

We point out that for a large class of parametrized theories, there is a constant in the constrained Hamiltonian which drops out of the classical equations of motion in configuration space. Examples include the mass of a relativistic…

General Relativity and Quantum Cosmology · Physics 2009-10-22 A. Carlini , J. Greensite

Existence of a minimal observable length which has been indicated by string theory and quantum gravity, leads to a modification of Dirac equation. In this letter we find this modified Dirac equation and solve its eigenvalue problem for a…

High Energy Physics - Theory · Physics 2009-11-11 Kourosh Nozari , Mojdeh Karami

We analyze the observational constraints on the effective Brans-Dicke parameter and on the temporal variation of the effective gravitational constant within the context of the oscillating G model, a cosmological model based on a massive…

Astrophysics · Physics 2014-10-13 Jose A. Gonzalez , Hernando Quevedo , Marcelo Salgado , Daniel Sudarsky