6 research outputs found
GLAST and Lorentz violation
We study possible Lorentz violations by means of gamma-ray bursts (GRB) with
special focus on the Large Array Telescope (LAT) of GLAST. We simulate bursts
with gtobssim and introduce a Lorentz violating term in the arrival times of
the photons. We further perturb these arrival times and energies with a
Gaussian distribution corresponding to the time resp. energy resolution of
GLAST. We then vary the photon flux in gtobssim in order to derive a relation
between the photon number and the standard deviation of the Lorentz violating
term. We conclude with the fact that our maximum likelihood method as first
developed in [1] is able to make a statement whether Nature breaks the Lorentz
symmetry if the number of bursts with known redshifts is of the order of 100.Comment: 13 pages, 8 figures and 2 tables, Accepted for publication by JCAP
after a couple of revision
Comparison of relativity theories with observer-independent scales of both velocity and length/mass
We consider the two most studied proposals of relativity theories with
observer-independent scales of both velocity and length/mass: the one discussed
by Amelino-Camelia as illustrative example for the original proposal
(gr-qc/0012051) of theories with two relativistic invariants, and an
alternative more recently proposed by Magueijo and Smolin (hep-th/0112090). We
show that these two relativistic theories are much more closely connected than
it would appear on the basis of a naive analysis of their original
formulations. In particular, in spite of adopting a rather different formal
description of the deformed boost generators, they end up assigning the same
dependence of momentum on rapidity, which can be described as the core feature
of these relativistic theories. We show that this observation can be used to
clarify the concepts of particle mass, particle velocity, and
energy-momentum-conservation rules in these theories with two relativistic
invariants.Comment: 21 pages, LaTex. v2: Andrea Procaccini (contributing some results
from hia Laurea thesis) is added to the list of authors and the paper
provides further elements of comparison between DSR1 and DSR2, including the
observation that both lead to the same formula for the dependence of momentum
on rapidit
Quantum-gravity-motivated Lorentz-symmetry tests with laser interferometers
We consider the implications for laser interferometry of the
quantum-gravity-motivated modifications in the laws of particle propagation,
which are presently being considered in attempts to explain puzzling
observations of ultra-high-energy cosmic rays. We show that there are
interferometric setups in which the Planck-scale effect on propagation leads to
a characteristic signature. A naive estimate is encouraging with respect to the
possibility of achieving Planck-scale sensitivity, but we also point out some
severe technological challenges which would have to be overcome in order to
achieve this sensitivity.Comment: 17 pages, 3 figure
A new Doubly Special Relativity theory from a quantum Weyl-Poincare algebra
A mass-like quantum Weyl-Poincare algebra is proposed to describe, after the
identification of the deformation parameter with the Planck length, a new
relativistic theory with two observer-independent scales (or DSR theory).
Deformed momentum representation, finite boost transformations, range of
rapidity, energy and momentum, as well as position and velocity operators are
explicitly studied and compared with those of previous DSR theories based on
kappa-Poincare algebra. The main novelties of the DSR theory here presented are
the new features of momentum saturation and a new type of deformed position
operators.Comment: 13 pages, LaTeX; some references and figures added, and terminology
is more precis