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In this paper we present noncommutative version of scalar field cosmology. We find the noncommutative Friedmann equations as well as the noncommutative Klein-Gordon equation. Interestingly the noncommutative contributions are only present…

General Relativity and Quantum Cosmology · Physics 2011-03-02 W. Guzmán , M. Sabido , J. Socorro

The Berezin-Klauder-Toeplitz ("anti-Wick") quantization or "non-commutative reading" of the complex plane, viewed as the phase space of a particle moving on the line, is derived from the resolution of the unity provided by the standard (or…

A calculation by Jacobson [1] strongly implies that the field equations which describe gravity are emergent phenomena. In this paper, the method is extended to the case of a non-commutative spacetime. By making use of a non-commutative…

High Energy Physics - Theory · Physics 2015-05-21 Simon Moolman

We show that the cosmological constant appears as a Lagrange multiplier if nature is described by a canonical noncommutative spacetime. It is thus an arbitrary parameter unrelated to the action and thus to vacuum fluctuations. The…

High Energy Physics - Theory · Physics 2008-11-26 Xavier Calmet

We formulate the quantum mechanics of the solutions of a Klein-Gordon-type field equation: (\partial_t^2+D)\psi(t)=0, where D is a positive-definite operator acting in a Hilbert space \tilde H. We determine all the positive-definite inner…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Ali Mostafazadeh

Gazeau-Klauder coherent states in noncommutative quantum mechanics are considered. We find that these states share similar properties to those of ordinary canonical coherent states in the sense that they saturate the related position…

High Energy Physics - Theory · Physics 2015-05-13 J Ben Geloun , F G Scholtz

We derive quantum kinetic equations for scalar fields undergoing coherent evolution either in time (coherent particle production) or in space (quantum reflection). Our central finding is that in systems with certain space-time symmetries,…

High Energy Physics - Phenomenology · Physics 2014-11-18 Matti Herranen , Kimmo Kainulainen , Pyry Matti Rahkila

In this article, I have considered a real scalar field theory and able to show that under Bogoliubov transformation in infinite volume limit or thermodynamic limit the transformed Hamiltonian no longer invariant under U(1) action defined…

General Physics · Physics 2018-06-05 Susobhan Mandal

We present a study of energy density and pressure of a free real scalar quantum field after its decoupling from a thermal bath in the spatially flat Friedman-Lema\^itre-Robertson-Walker space-time by solving the Klein-Gordon equation both…

General Relativity and Quantum Cosmology · Physics 2025-04-15 F. Becattini , D. Roselli

We construct quantum field theory in an analogue curved spacetime in Bose-Einstein condensates based on the Bogoliubov-de Gennes equations, by exactly relating quantum particles in curved spacetime with Bogoliubov quasiparticle excitations…

Other Condensed Matter · Physics 2010-11-02 Yasunari Kurita , Michikazu Kobayashi , Takao Morinari , Makoto Tsubota , Hideki Ishihara

We solve the relativistic Klein--Gordon equation for a light particle gravitationally bound to a heavy central mass, with the gravitational interaction prescribed by the metric of a spherically symmetric space-time. Metrics are considered…

General Relativity and Quantum Cosmology · Physics 2018-06-13 R. D. Lehn , S. S. Chabysheva , J. R. Hiller

A novel geometric model of a noncommutative plane has been constructed. We demonstrate that it can be construed as a toy model for describing and explaining the basic features of physics in a noncommutative spacetime from a field theory…

High Energy Physics - Theory · Physics 2009-11-10 Subir Ghosh

Gravitational particle production is a minimal contribution to reheating the Universe after the end of inflation. To study this production channel, two different approaches have commonly been considered, one of which is based on the…

Cosmology and Nongalactic Astrophysics · Physics 2022-09-08 Kunio Kaneta , Sung Mook Lee , Kin-ya Oda

The concept of a particle is ambiguous in quantum field theory. It is generally agreed that particles depend not only on spacetime, but also on coordinates used to parametrise spacetime points. One of us has in contrast proposed a…

General Relativity and Quantum Cosmology · Physics 2026-04-07 V. A. Emelyanov , D. Robertz

Quantized space described by time reversal invariant and rotationally invariant noncommutative algebra of canonical type is studied. A particle in uniform field is considered. We find exactly the energy of a particle in uniform field in the…

High Energy Physics - Theory · Physics 2021-02-22 Kh. P. Gnatenko , Kh. I. Stakhur , A. V. Kryzhova

In the present work, we study the noncommutative version of a quantum cosmology model. The model has a Friedmann-Robertson-Walker geometry, the matter content is a radiative perfect fluid and the spatial sections have positive constant…

General Relativity and Quantum Cosmology · Physics 2016-05-05 G. Oliveira-Neto , G. A. Monerat , E. V. Corrêa Silva , C. Neves , L. G. Ferreira Filho

In these lectures we consider some topics of Quantum Field Theory in Curved Space. In the first one particle creation in curved space is studied from a mathematical point of view, especially, particle production at a given time using the so…

General Relativity and Quantum Cosmology · Physics 2011-02-07 Jaume Haro

Given a positive energy solution of the Klein-Gordon equation, the motion of the free, spinless, relativistic particle is described in a fixed Lorentz frame by a Markov diffusion process with non-constant diffusion coefficient. Proper time…

Quantum Physics · Physics 2015-06-26 Michele Pavon

Considering an exactly solvable local quantum theory of a scalar field interacting with a $\delta$-shaped time-dependent potential we calculate the Bogoliubov coefficients analytically and determine the spectrum of created particles. We…

High Energy Physics - Theory · Physics 2021-04-21 Jens Boos , Valeri P. Frolov , Andrei Zelnikov

In this paper we investigate the bound state problem of nonrelativistic quantum particles on a conical surface. This kind of surface appears as a topological defect in ordinary semiconductors as well as in graphene sheets. Specifically, we…

Quantum Physics · Physics 2012-12-13 C. Filgueiras , E. O. Silva , F. M. Andrade