271 research outputs found

    Natural extension of the Generalised Uncertainty Principle

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    We discuss a gedanken experiment for the simultaneous measurement of the position and momentum of a particle in de Sitter spacetime. We propose an extension of the so-called generalized uncertainty principle (GUP) which implies the existence of a minimum observable momentum. The new GUP is directly connected to the nonzero cosmological constant, which becomes a necessary ingredient for a more complete picture of the quantum spacetime.Comment: 4 pages, 1 figure, v2 with added references, revised and extended as published in CQ

    Some Aspects of Minimal Length Quantum Mechanics

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    String theory, quantum geometry, loop quantum gravity and black hole physics all indicate the existence of a minimal observable length on the order of Planck length. This feature leads to a modification of Heisenberg uncertainty principle. Such a modified Heisenberg uncertainty principle is referred as gravitational uncertainty principle(GUP) in literatures. This proposal has some novel implications on various domains of theoretical physics. Here, we study some consequences of GUP in the spirit of Quantum mechanics. We consider two problem: a particle in an one-dimensional box and momentum space wave function for a "free particle". In each case we will solve corresponding perturbational equations and compare the results with ordinary solutions.Comment: 9 pages, one eps figur

    Black hole thermodynamics with generalized uncertainty principle

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    In the standard viewpoint, the temperature of a stationary black hole is proportional to its surface gravity, TH=â„ŹÎş/2Ď€T_H=\hbar\kappa/2\pi. This is a semiclassical result and the quantum gravity effects are not taken into consideration. This Letter explores a unified expression for the black hole temperature in the sense of a generalized uncertainty principle(GUP). Our discussion involves a heuristic analysis of a particle which is absorbed by the black hole. Besides a class of static and spherically symmetric black holes, an axially symmetric Kerr-Newman black hole is considered. Different from the existing literature, we suggest that the black hole's irreducible mass represent the characteristic size in the absorption process. The information capacity of a remnant is also discussed by Bousso's D-bound in de Sitter spacetime.Comment: 18 pages, great improvement on the first version; a Kerr-Newman black hole is considere

    Black Hole Entropy: a spacetime foam approach

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    The spacetime foam structure is reviewed briefly (topogical fluctuations and virtual black hole possibility; equation of state of the foam). A model of space foam at the surface of the event horizon is introduced. The model is applied to the calculus of the number of states of a black hole, of its entropy and of other thermodynamical properties. A formula for the number of microholes on the surface of the event horizon is derived. Thermodynamical properties of the event horizon are extended to thermodynamical properties of the space. On the basis of the previous results, the possibility of micro black holes creation by the Unruh Effect is investigated.Comment: 23 pages, no figures, postscript file gzipped,to be published in Classical and Quantum Gravity, July 199

    Wave Packets Propagation in Quantum Gravity

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    Wave packet broadening in usual quantum mechanics is a consequence of dispersion behavior of the medium which the wave propagates in it. In this paper, we consider the problem of wave packet broadening in the framework of Generalized Uncertainty Principle(GUP) of quantum gravity. New dispersion relations are derived in the context of GUP and it has been shown that there exists a gravitational induced dispersion which leads to more broadening of the wave packets. As a result of these dispersion relations, a generalized Klein-Gordon equation is obtained and its interpretation is given.Comment: 9 pages, no figur

    Minimum black hole mass from colliding Gaussian packets

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    We study the formation of a black hole in the collision of two Gaussian packets. Rather than following their dynamical evolution in details, we assume a horizon forms when the mass function for the two packets becomes larger than half the flat areal radius, as it would occur in a spherically symmetric geometry. This simple approximation allows us to determine the existence of a minimum black hole mass solely related to the width of the packets. We then comment on the possible physical implications, both in classical and quantum physics, and models with extra spatial dimensions.Comment: 11 pages, 4 figure

    Generalized Uncertainty Principle, Extra-dimensions and Holography

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    We consider Uncertainty Principles which take into account the role of gravity and the possible existence of extra spatial dimensions. Explicit expressions for such Generalized Uncertainty Principles in 4+n dimensions are given and their holographic properties investigated. In particular, we show that the predicted number of degrees of freedom enclosed in a given spatial volume matches the holographic counting only for one of the available generalizations and without extra dimensions.Comment: LaTeX, 13 pages, accepted for publication in Class. Quantum Gra

    On the Existence of the Logarithmic Correction Term in Black Hole Entropy-Area Relation

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    In this paper we consider a model universe with large extra dimensions to obtain a modified black hole entropy-area relation. We use the generalized uncertainty principle to find a relation between the number of spacetime dimensions and the presence or vanishing of logarithmic prefactor in the black hole entropy-area relation. Our calculations are restricted to the microcanonical ensembles and we show that in the modified entropy-area relation, the microcanonical logarithmic prefactor appears only when spacetime has an even number of dimensions.Comment: 9 Pages, No Figure
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