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Related papers: Causality in noncommutative spacetime

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The causal spacetimes admitting a covariantly constant null vector provide a connection between relativistic and non-relativistic physics. We explore this relationship in several directions. We start proving a formula which relates the…

General Relativity and Quantum Cosmology · Physics 2012-11-13 E. Minguzzi

The purpose of this paper is to challenge the existing paradigm on which contemporary models of generalised uncertainty relations (GURs) are based, that is, the assumption of modified commutation relations. We review an array of theoretical…

General Relativity and Quantum Cosmology · Physics 2023-02-17 Matthew J. Lake , A. Watcharapasorn

In conformally invariant quantum field theories one encounters besides the standard DHR superselection theory based on spacelike (Einstein-causal) commutation relations and their Haag duality another timelike (''Huygens'') based…

High Energy Physics - Theory · Physics 2007-05-23 Bert Schroer

We examine the dynamical behavior of matter coupled to gravity in the context of a linear Klein-Gordon equation coupled to a Friedman-Robertson-Walker metric. The resulting ordinary differential equations can be decoupled, the effect of…

General Relativity and Quantum Cosmology · Physics 2007-05-23 T. Christodoulakis , C. Helias , P. G. Kevrekidis , I. G. Kevrekidis , G. O. Papadopoulos

We present a relativistic formulation of noncommutative mechanics were the object of noncommutativity $\theta^{\mu\nu}$ is considered as an independent quantity. Its canonical conjugate momentum is also introduced, what permits to obtain an…

High Energy Physics - Theory · Physics 2010-05-25 R. Amorim , E. M. C. Abreu , W. G. Ramirez

We study a new approach to generally covariant quantum mechanics applied in the case of an FLRW cosmological background. For positive spatial curvature we find a discrete series of solutions of the Klein-Gordon equation that can reasonably…

General Relativity and Quantum Cosmology · Physics 2025-11-13 Edwin Beggs , Shahn Majid

We investigate torsion-driven cosmological dynamics within the framework of Einstein-Cartan gravity using the De Donder-Weyl Hamiltonian formalism, where the tetrad and Lorentz connection act as independent variables and the Hamiltonian…

General Relativity and Quantum Cosmology · Physics 2026-02-18 Aarav Shah , M. Yu. Khlopov , M. Krasnov

Quantization of coordinates leads to the non-commutative product of deformation quantization, but is also at the roots of string theory, for which space-time coordinates become the dynamical fields of a two-dimensional conformal quantum…

High Energy Physics - Theory · Physics 2008-11-26 Sebastian Guttenberg , Manfred Herbst , Maximilian Kreuzer , Radoslav Rashkov

We study a scalar field on a noncommutative model of spacetime, the fuzzy de Sitter space, which is based on the algebra of the de Sitter group $SO(1,d)$ and its unitary irreducible representations. We solve the Klein-Gordon equation in…

High Energy Physics - Theory · Physics 2024-03-19 Bojana Brkic , Ilija Buric , Maja Buric , Dusko Latas

We study the Dirac and the klein-Gordon oscillators in a noncommutative space. It is shown that the Klein-Gordon oscillator in a noncommutative space has a similar behaviour to the dynamics of a particle in a commutative space and in a…

High Energy Physics - Theory · Physics 2007-05-23 M. Mohadesi , B. Mirza

It is shown that, in the non-relativistic limit, causal fermion systems give rise to an effective collapse theory. The nonlinear and stochastic correction terms to the Schr\"odinger equation are derived from the causal action principle. The…

Mathematical Physics · Physics 2024-09-12 Felix Finster , Johannes Kleiner , Claudio F. Paganini

Field theories on canonical noncommutative spacetimes, which are being studied also in connection with string theory, and on $\kappa$-Minkowski spacetime, which is a popular example of Lie-algebra noncommutative spacetime, can be naturally…

High Energy Physics - Theory · Physics 2017-08-23 Giovanni Amelino-Camelia , Michele Arzano , Luisa Doplicher

A quantum causal topology is presented. This is modeled after a non-commutative scheme type of theory for the curved finitary spacetime sheaves of the non-abelian incidence Rota algebras that represent `gravitational quantum causal sets'.…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Ioannis Raptis

Generalized solutions of the standard gauge transformation equations are presented and discussed in physical terms. They go beyond the usual Dirac phase factors and they exhibit nonlocal quantal behavior, with the well-known Relativistic…

Quantum Physics · Physics 2015-05-28 Konstantinos Moulopoulos

Within the spirit of Dirac's canonical quantization, noncommutative spacetime field theories are introduced by making use of the reparametrization invariance of the action and of an arbitrary non-canonical symplectic structure. This…

High Energy Physics - Theory · Physics 2008-11-26 Marcos Rosenbaum , J. David Vergara , L. Roman Juarez

Causal set theory is an intrinsically nonlocal approach to quantum gravity, inheriting its nonlocality from Lorentzian nonlocality. This nonlocality causes problems in defining differential operators -- such as the d'Alembert operator, a…

General Relativity and Quantum Cosmology · Physics 2025-06-24 Marián Boguñá , Dmitri Krioukov

In fundamental theories that accounts for quantum gravitational effects, the spacetime causal structure is expected to be quantum uncertain. Previous studies of quantum causal structure focused on finite-dimensional systems. Here we present…

Quantum Physics · Physics 2019-02-18 Ding Jia

We study general properties of certain Lorentz invariant noncommutative quantum field theories proposed in the literature. We show that causality in those theories does not hold, in contrast to the canonical noncommutative field theory with…

High Energy Physics - Theory · Physics 2008-11-26 Sami Saxell

We show that there exists a canonical topology, naturally connected with the causal site of J. D. Christensen and L. Crane, a pointless algebraic structure motivated by quantum gravity. Taking a causal site compatible with Minkowski space,…

Mathematical Physics · Physics 2013-08-05 Martin Maria Kovár

Causal set theory is an approach to quantum gravity in which spacetime is fundamentally discrete at the Planck scale and takes the form of a Lorentzian lattice, or "causal set", from which continuum spacetime emerges in a large-scale…

High Energy Physics - Theory · Physics 2024-05-15 Emma Albertini , Fay Dowker , Arad Nasiri , Stav Zalel