1,623 research outputs found
Extended uncertainty principle and the geometry of (anti)-de Sitter space
It has been proposed that on (anti)-de Sitter background, the Heisenberg
uncertainty principle should be modified by the introduction of a term
proportional to the cosmological constant. We show that this modification of
the uncertainty principle can be derived straightforwardly from the geometric
properties of (anti)-de Sitter spacetime. We also discuss the connection
between the so-called extended generalized uncertainty principle and triply
special relativity.Comment: 8 pages, plain TeX, references adde
Strongly Scale-dependent Non-Gaussianity
We discuss models of primordial density perturbations where the
non-Gaussianity is strongly scale-dependent. In particular, the non-Gaussianity
may have a sharp cut-off and be very suppressed on large cosmological scales,
but sizeable on small scales. This may have an impact on probes of
non-Gaussianity in the large-scale structure and in the cosmic microwave
background radiation anisotropies.Comment: 4 page
Symmetry breaking aspects of the effective Lagrangian for quantum black holes
The physical excitations entering the effective Lagrangian for quantum black
holes are related to a Goldstone boson which is present in the Rindler limit
and is due to the spontaneous breaking of the translation symmetry of the
underlying Minkowski space. This physical interpretation, which closely
parallels similar well-known results for the effective stringlike description
of flux tubes in QCD, gives a physical insight into the problem of describing
the quantum degrees of freedom of black holes. It also suggests that the
recently suggested concept of 'black hole complementarity' emerges at the
effective Lagrangian level rather than at the fundamental level.Comment: 11 pages, Latex,1 figur
Non-Unitary and Unitary Transitions in Generalized Quantum Mechanics, New Small Parameter and Information Problem Solving
Quantum Mechanics of the Early Universe is considered as deformation of a
well-known Quantum Mechanics. Similar to previous works of the author, the
principal approach is based on deformation of the density matrix with
concurrent development of the wave function deformation in the respective
Schr{\"o}dinger picture, the associated deformation parameter being interpreted
as a new small parameter. It is demonstrated that the existence of black holes
in the suggested approach in the end twice causes nonunitary transitions
resulting in the unitarity. In parallel this problem is considered in other
terms: entropy density, Heisenberg algebra deformation terms, respective
deformations of Statistical Mechanics, - all showing the identity of the basic
results. From this an explicit solution for Hawking's informaion paradox has
been derived.Comment: 18 page
Wave Packets Propagation in Quantum Gravity
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
Covariant Helicity-Coupling Amplitudes: A New Formulation
We have worked out covariant amplitudes for any two-body decay of a resonance
with an arbitrary non-zero mass, which involves arbitrary integer spins in the
initial and the final states. One key new ingredient for this work is the
application of the total intrinsic spin operator which is given
directly in terms of the generators of the Poincar\'e group.
Using the results of this study, we show how to explore the Lorentz factors
which appear naturally, if the momentum-space wave functions are used to form
the covariant decay amplitudes. We have devised a method of constructing our
covariant decay amplitudes, such that they lead to the Zemach amplitudes when
the Lorentz factors are set one
Nonrenormalization theorems for N=2 Super Yang-Mills
The BRST algebraic proofs of the the nonrenormalization theorems for the beta
functions of N=2 and N=4 Super Yang-Mills theories are reviewed.Comment: 3 pages, contribution to SUSY 2000 Encyclopedi
Some Aspects of Minimal Length Quantum Mechanics
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
Gravitational Wave Bursts from Cosmic Superstrings with Y-junctions
Cosmic superstring loops generically contain strings of different tensions
that meet at Y-junctions. These loops evolve non-periodically in time, and have
cusps and kinks that interact with the junctions. We study the effect of
junctions on the gravitational wave signal emanating from cosmic string cusps
and kinks. We find that earlier results on the strength of individual bursts
from cusps and kinks on strings without junctions remain largely unchanged, but
junctions give rise to additional contributions to the gravitational wave
signal coming from strings expanding at the speed of light at a junction and
kinks passing through a junction.Comment: 20 pages, 5 figure
Pure States, Mixed States and Hawking Problem in Generalized Quantum Mechanics
This paper is the continuation of a study into the information paradox
problem started by the author in his earlier works. As previously, the key
instrument is a deformed density matrix in quantum mechanics of the early
universe. It is assumed that the latter represents quantum mechanics with
fundamental length. It is demonstrated that the obtained results agree well
with the canonical viewpoint that in the processes involving black holes pure
states go to the mixed ones in the assumption that all measurements are
performed by the observer in a well-known quantum mechanics. Also it is shown
that high entropy for Planck remnants of black holes appearing in the
assumption of the Generalized Uncertainty Relations may be explained within the
scope of the density matrix entropy introduced by the author previously. It is
noted that the suggested paradigm is consistent with the Holographic Principle.
Because of this, a conjecture is made about the possibility for obtaining the
Generalized Uncertainty Relations from the covariant entropy bound at high
energies in the same way as R. Bousso has derived Heisenberg uncertainty
principle for the flat space.Comment: 12 pages,no figures,some corrections,new reference
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