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Related papers: Time Discretization From Noncommutativity

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Spacetime geometry is twisted (deformed) into noncommutative spacetime geometry, where functions and tensors are now star-multiplied. Consistently, spacetime diffeomorhisms are twisted into noncommutative diffeomorphisms. Their deformed Lie…

High Energy Physics - Theory · Physics 2016-09-06 Paolo Aschieri

The noncommutativity concept has wide range of applications in physical and mathematical theories. Noncommutativity in the position-time coordinates concerns the microscale structure of space-time. the noncommutativity is an intrinsic…

General Relativity and Quantum Cosmology · Physics 2023-10-24 Behrooz Malekolkalami , Taimur Mohammadi

In this article we consider the bounds on the noncommutative nature of space-time. We argue that these bounds are extremely model dependent. In the only phenomenologically viable framework, i.e. when the fields are taken to be in the…

High Energy Physics - Phenomenology · Physics 2011-09-13 Xavier Calmet

We examine the time variation of a previously-uninvestigated fundamental dimensionless constant. Constraints are placed on this time variation using historical measurements. A model is presented for the time variation, and it is shown to…

Cosmology and Nongalactic Astrophysics · Physics 2009-04-01 Robert J. Scherrer

Time reversal symmetry occupies a distinctive role in quantum mechanics, fundamentally requiring an anti-unitary operator to ensure a physically consistent representation. As such, the time reversal operator combines a unitary…

General Relativity and Quantum Cosmology · Physics 2026-03-27 Ovidiu Racorean

In a quantum gravity theory, it is expected that the classical notion of spacetime disappears, leading to a quantum structure with new properties. A possible way to take into account these quantum effects is through a noncommutativity of…

High Energy Physics - Theory · Physics 2023-07-25 Giulia Gubitosi , Fedele Lizzi , José Javier Relancio , Patrizia Vitale

Quantum non-local correlations and the acausal, spooky action at a distance suggest a discord between quantum theory and special relativity. We propose a resolution for this discord by first observing that there is a problem of time in…

General Relativity and Quantum Cosmology · Physics 2016-11-15 Shreya Banerjee , Sayantani Bera , T. P. Singh

A quantum clock cannot be modeled as a point mass moving along a single geodesic if it is in a state with nonzero position fluctuations. Instead, it is an extended object subject to tidal forces and a superposition of time dilations at…

Quantum Physics · Physics 2025-03-11 Joseph Balsells , Martin Bojowald

In previous work, we developed quantum physics on the Moyal plane with time-space noncommutativity, basing ourselves on the work of Doplicher et al.. Here we extend it to certain noncommutative versions of the cylinder, $\mathbb{R}^{3}$ and…

High Energy Physics - Theory · Physics 2008-11-26 A. P. Balachandran , T. R. Govindarajan , A. G. Martins , P. Teotonio-Sobrinho

We study the reparametrization invariant system of a classical relativistic particle moving in (5+1) dimensions, of which two internal ones are compactified to form a torus. A discrete physical time is constructed based on a quasi-local…

General Relativity and Quantum Cosmology · Physics 2010-11-19 H. -T. Elze

I present a way to visualize the concept of curved spacetime. The result is a curved surface with local coordinate systems (Minkowski Systems) living on it, giving the local directions of space and time. Relative to these systems, special…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Rickard Jonsson

We propose a variation of spacetime noncommutative field theory to realize the stringy spacetime uncertainty relation without breaking any of the global symmetries of the homogeneous isotropic universe. We study the spectrum of metric…

High Energy Physics - Theory · Physics 2009-11-07 Robert Brandenberger , Pei-Ming Ho

It is brought forward that viable theories of the physical world that have no variable at all that can play the role of time, do not exist; some notion of time is one of the very first ingredients a candidate theory should possess. Almost…

Quantum Physics · Physics 2018-04-05 Gerard t Hooft

The characterization of non-stationary signals requires joint time and frequency information. However, time (t) and frequency (omega) being non-commuting variables there cannot be a joint probability density in the (t,omega) plane and the…

Data Analysis, Statistics and Probability · Physics 2007-05-23 V. I. Man'ko , R. Vilela Mendes

We introduce a self-adjoint operator that indicates the direction of time within the framework of standard quantum mechanics. That is, as a function of time its expectation value decreases monotonically for any initial state. This operator…

Quantum Physics · Physics 2008-02-19 Y. Strauss , J. Silman , S. Machnes , L. P. Horwitz

We define a noncommutative Lorentz symmetry for canonical noncommutative spaces. The noncommutative vector fields and the derivatives transform under a deformed Lorentz transformation. We show that the star product is invariant under…

High Energy Physics - Theory · Physics 2009-11-10 Xavier Calmet

Classical mechanics, relativity, electrodynamics and quantum mechanics are often depicted as separate realms of physics, each with its own formalism and notion. This remains unsatisfactory with respect to the unity of nature and to the…

History and Philosophy of Physics · Physics 2018-02-07 C. Baumgarten

After a review of the existing theory of non-inertial frames and mathematical observers in Minkowski space-time we give the explicit expression of a family of such frames obtained from the inertial ones by means of point-dependent Lorentz…

General Relativity and Quantum Cosmology · Physics 2015-05-20 Horace W. Crater , Luca Lusanna

Space-like and time-like invariant space-time intervals are used to analyse measurements of spatial and temporal distances. The former are found to be Lorentz invariant --there is no `relativistic length contraction', whereas the latter…

General Physics · Physics 2009-09-01 J. H. Field

A method of measuring time intervals by a single observer proposed by Crowell is extended to the more general case when the events separated by the time interval take place at two points characterized by the same y=y' space coordinates. We…

General Physics · Physics 2008-12-04 Bernhard Rothenstein , Ioan Damian