15,099 research outputs found
Relaxing Lorentz invariance in general perturbative anomalies
We analyze the role of Lorentz symmetry in the perturbative non-gravitational
anomalies for a single family of fermions. The theory is assumed to be
translational invariant, power-counting renormalizable and based on a local
action, but is allowed to have general Lorentz violating operators. We study
the conservation of global and gauge currents associate with general internal
symmetry groups and find, by using a perturbative approach, that Lorentz
symmetry does not participate in the clash of symmetries that leads to the
anomalies. We first analyze the triangle graphs and prove that there are
regulators for which the anomalous part of the Ward identities exactly
reproduces the Lorentz invariant case. Then we show, by means of a regulator
independent argument, that the anomaly cancellation conditions derived in
Lorentz invariant theories remain necessary ingredients for anomaly freedom.Comment: 18 pages, 1 figure. Few comments added. Article published in Physical
Review
Path-Integral Formulation of Pseudo-Hermitian Quantum Mechanics and the Role of the Metric Operator
We provide a careful analysis of the generating functional in the path
integral formulation of pseudo-Hermitian and in particular PT-symmetric quantum
mechanics and show how the metric operator enters the expression for the
generating functional.Comment: Published version, 4 page
Position space versions of Magueijo-Smolin doubly special relativity proposal and the problem of total momentum
We present and discuss two different possibilities to construct position
space version for Magueijo-Smolin (MS) doubly special relativity proposal. The
first possibility is to start from ordinary special relativity and then to
define conserved momentum in special way. It generates MS invariant as well as
nonlinear MS transformations on the momentum space, leading to consistent
picture for one-particle sector of the theory. The second possibility is based
on the following observation. Besides the nonlinear MS transformations, the MS
energy-momentum relation is invariant also under some inhomogeneous linear
transformations. The latter are induced starting from linearly realized Lorentz
group in five-dimensional position space. Particle dynamics and kinematics are
formulated starting from the corresponding five-dimensional interval. There is
no problem of total momentum in the theory. The formulation admits two observer
independent scales, the speed of light, , and with dimension of
velocity. We speculate on different possibilities to relate with
fundamental constants. In particular, expression of in terms of vacuum
energy suggests emergence of (minimum) quantum of mass.Comment: Latex twice, 14 pages, revised in accordance with the version
publishedin Phys. Rev.
The Cardy-Verlinde equation in a spherical symmetric gravitational collapse
The Cardy-Verlinde formula is analyzed in the contest of the gravitational
collapse. Starting from the holographic principle, we show how the equations
for a homogeneous and isotropic gravitational collapse describe the formation
of the black hole entropy. Some comments on the role of the entangled entropy
and the connection with the c-theorem are made
The resultant parameters of effective theory
This is the 4-th paper in the series devoted to a systematic study of the
problem of mathematically correct formulation of the rules needed to manage an
effective field theory. Here we consider the problem of constructing the full
set of essential parameters in the case of the most general effective
scattering theory containing no massless particles with spin J > 1/2. We
perform the detailed classification of combinations of the Hamiltonian coupling
constants and select those which appear in the expressions for renormalized
S-matrix elements at a given loop order.Comment: 21 pages, 4 LaTeX figures, submitted to Phys. Rev.
Effects of outdoor exposure on solar cell modules in the ERDA/NASA Lewis Research Center Systems Test Facility
The effects of outdoor exposure were determined by comparing standard I-V data obtained for the as-received modules with similar data obtained after removal from the field and cleaning with detergent solution. All modules measured in this way exhibited nonrecoverable degradation in P sub maximum varying from 4 to 7 percent. One module exposed for 41 days exhibited partial cell discoloration, loss of front surface metallization over the discolored portion, and a decrease in P sub maximum of 7 percent, tentatively attributed to cell damage. Measurements before and after cleaning showed a recoverable degradation due to dirt accumulation. This recoverable loss in power was 11 percent after 245 days in the field for one brand of module, 6 percent after 48 days for another brand, and 4 1/2 percent for the third brand
Anisotropic cosmological models with spinor and scalar fields and viscous fluid in presence of a term: qualitative solutions
The study of a self-consistent system of interacting spinor and scalar fields
within the scope of a Bianchi type I (BI) gravitational field in presence of a
viscous fluid and term has been carried out. The system of equations
defining the evolution of the volume scale of BI universe, energy density and
corresponding Hubble constant has been derived. The system in question has been
thoroughly studied qualitatively. Corresponding solutions are graphically
illustrated. The system in question is also studied from the view point of blow
up. It has been shown that the blow up takes place only in presence of
viscosity.Comment: 18 pages, 14 figures, 12 Tables, section "Basic equations" has been
rewritte
Cosmic balloons
Cosmic balloons, consisting of relativistic particles trapped inside a
spherical domain wall, may be created in the early universe. We calculate the
balloon mass as a function of the radius and the energy density
profile, , including the effects of gravity. At the maximum balloon
mass for any value of the mass density of the wall.Comment: 9 pages, LaTeX, 2 figures in separate file, UPTP-93-1
S-Matrix on the Moyal Plane: Locality versus Lorentz Invariance
Twisted quantum field theories on the Groenewold-Moyal plane are known to be
non-local. Despite this non-locality, it is possible to define a generalized
notion of causality. We show that interacting quantum field theories that
involve only couplings between matter fields, or between matter fields and
minimally coupled U(1) gauge fields are causal in this sense. On the other
hand, interactions between matter fields and non-abelian gauge fields violate
this generalized causality. We derive the modified Feynman rules emergent from
these features. They imply that interactions of matter with non-abelian gauge
fields are not Lorentz- and CPT-invariant.Comment: 15 pages, LaTeX, 1 figur
Using Perturbative Least Action to Recover Cosmological Initial Conditions
We introduce a new method for generating initial conditions consistent with
highly nonlinear observations of density and velocity fields. Using a variant
of the Least Action method, called Perturbative Least Action (PLA), we show
that it is possible to generate several different sets of initial conditions,
each of which will satisfy a set of highly nonlinear observational constraints
at the present day. We then discuss a code written to test and apply this
method and present the results of several simulations.Comment: 24 pages, 6 postscript figures. Accepted for publication in
Astrophysical Journa
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