8,218 research outputs found
Spontaneous emission of graviton by a quantum bouncer
Spontaneous emission of graviton rates for the quantum bouncer states are
evaluated
Dihedral Families of Quarks, Leptons and Higgs Bosons
We consider finite groups of small order for family symmetry. It is found
that the binary dihedral group Q_6, along with the assumption that the Higgs
sector is of type II, predicts mass matrix of a nearest neighbor interaction
type for quarks and leptons. We present a supersymmetric model based on Q_6
with spontaneously induced CP phases. The quark sector contains 8 real
parameters with one independent phase to describe the quark masses and their
mixing. Predictions in the |V_{ub}|-bar{eta}, |V_{ub}|-sin 2 beta(phi_1) and
|V_{ub}|-|V_{td}/V_{ts}| planes are given. The lepton sector contains also 9
parameters. A normal as well as an inverted spectrum of neutrino masses is
possible, and we compute V_{e3}. We find that |V_{e3}|^2 > 10^{-4} in the case
of a normal spectrum, and |V_{e3}|^2 >8 10^{-4} in the case of an inverted
spectrum. It is also found that Q_6 symmetry forbids all Baryon number
violating terms of d=4, and the contributions to EDMs from the A terms vanish
in this model.Comment: 27 pages, 8 figure
Quantum Theory and Galois Fields
We discuss the motivation and main results of a quantum theory over a Galois
field (GFQT). The goal of the paper is to describe main ideas of GFQT in a
simplest possible way and to give clear and simple arguments that GFQT is a
more natural quantum theory than the standard one. The paper has been prepared
as a presentation to the ICSSUR' 2005 conference (Besancon, France, May 2-6,
2005).Comment: Latex, 24 pages, 1 figur
On the Gauged Non-compact Spin System
We examine classical and quantum aspects of the planar non-compact spin
system coupled with Chern-Simons gauge field in the presence of background
charge. We first define our classical spin system as non- relativistic
non-linear sigma model in which the order parameter spin takes value in the
non-compact manifold . Although the naive model does not
allow any finite energy self dual solitons, it is shown that the gauged system
admits static Bogomol'nyi solitons with finite energy whose rotationally
symmetric soliton solutions are analyzed in detail. We also discuss the large
spin limit in which the self-dual equation reduces to the well-known gauged
non- linear Schr\"odinger model or Abelian Higgs model, depending on the choice
of the background charge term. Then, we perform quantization of the model. We
find that the spin algebra satisfies anomalous commutation relations, and the
system is a field theoretic realization of the anyons.Comment: 21 pages, Latex, 3 figures include
Radiation damage in high voltage silicon solar cells
Three high open-circuit voltage cell designs based on 0.1 ohm-cm p-type silicon were irradiated with 1 MeV electrons and their performance determined to fluences as high as 10 to the 15th power/sq cm. Of the three cell designs, radiation induced degradation was greatest in the high-low emitter (HLE cell). The diffused and ion implanted cells degraded approximately equally but less than the HLE cell. Degradation was greatest in an HLE cell exposed to X-rays before electron irradiation. The cell regions controlling both short-circuit current and open-circuit voltage degradation were defined in all three cell types. An increase in front surface recombination velocity accompanied time dependent degradation of an HLE cell after X-irradiation. It was speculated that this was indirectly due to a decrease in positive charge at the silicon-oxide interface. Modifications aimed at reducing radiation induced degradation are proposed for all three cell types
Brans-Dicke theory: Jordan vs Einstein Frame
It is well known that, in contrast to general relativity, there are two
conformally related frames, the Jordan frame and the Einstein frame, in which
the Brans-Dicke theory, a prototype of generic scalar-tensor theory, can be
formulated. There is a long standing debate on the physical equivalence of the
formulations in these two different frames. It is shown here that gravitational
deflection of light to second order accuracy may observationally distinguish
the two versions of the Brans-Dicke theory.Comment: 10 pages, Accepted by Mod. Phys. Letts.
Exploring the structure of the quenched QCD vacuum with overlap fermions
Overlap fermions have an exact chiral symmetry on the lattice and are thus an
appropriate tool for investigating the chiral and topological structure of the
QCD vacuum. We study various chiral and topological aspects of quenched gauge
field configurations. This includes the localization and chiral properties of
the eigenmodes, the local structure of the ultraviolet filtered field strength
tensor, as well as the structure of topological charge fluctuations. We
conclude that the vacuum has a multifractal structure.Comment: 68 pages, 31 figures, file size: 1.7 MB (PDF
The Gauge Fields and Ghosts in Rindler Space
We consider 2d Maxwell system defined on the Rindler space with metric
ds^2=\exp(2a\xi)\cdot(d\eta^2-d\xi^2) with the goal to study the dynamics of
the ghosts. We find an extra contribution to the vacuum energy in comparison
with Minkowski space time with metric ds^2= dt^2-dx^2. This extra contribution
can be traced to the unphysical degrees of freedom (in Minkowski space). The
technical reason for this effect to occur is the property of Bogolubov's
coefficients which mix the positive and negative frequencies modes. The
corresponding mixture can not be avoided because the projections to positive
-frequency modes with respect to Minkowski time t and positive -frequency modes
with respect to the Rindler observer's proper time \eta are not equivalent. The
exact cancellation of unphysical degrees of freedom which is maintained in
Minkowski space can not hold in the Rindler space. In BRST approach this effect
manifests itself as the presence of BRST charge density in L and R parts. An
inertial observer in Minkowski vacuum |0> observes a universe with no net BRST
charge only as a result of cancellation between the two. However, the Rindler
observers who do not ever have access to the entire space time would see a net
BRST charge. In this respect the effect resembles the Unruh effect. The effect
is infrared (IR) in nature, and sensitive to the horizon and/or boundaries. We
interpret the extra energy as the formation of the "ghost condensate" when the
ghost degrees of freedom can not propagate, but nevertheless do contribute to
the vacuum energy. Exact computations in this simple 2d model support the claim
made in [1] that the ghost contribution might be responsible for the observed
dark energy in 4d FLRW universe.Comment: Final version to appear in Phys. Rev. D. Comments on relation with
energy momentum computations and few new refs are adde
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