3,341 research outputs found
Doubly Special Relativity with a minimum speed and the Uncertainty Principle
The present work aims to search for an implementation of a new symmetry in
the space-time by introducing the idea of an invariant minimum speed scale
(). Such a lowest limit , being unattainable by the particles, represents
a fundamental and preferred reference frame connected to a universal background
field (a vacuum energy) that breaks Lorentz symmetry. So there emerges a new
principle of symmetry in the space-time at the subatomic level for very low
energies close to the background frame (), providing a fundamental
understanding for the uncertainty principle, i.e., the uncertainty relations
should emerge from the space-time with an invariant minimum speed.Comment: 10 pages, 8 figures, Correlated paper in:
http://www.worldscientific.com/worldscinet/ijmpd?journalTabs=read. arXiv
admin note: substantial text overlap with arXiv:physics/0702095,
arXiv:0705.4315, arXiv:0709.1727, arXiv:0805.120
Cosmological gravitomagnetism and Mach's principle
The spin axes of gyroscopes experimentally define local non-rotating frames.
But what physical cause governs the time-evolution of gyroscope axes? We
consider linear perturbations of Friedmann-Robertson-Walker cosmologies with
k=0. We ask: Will cosmological vorticity perturbations exactly drag the spin
axes of gyroscopes relative to the directions of geodesics to quasars in the
asymptotic unperturbed FRW space? Using Cartan's formalism with local
orthonormal bases we cast the laws of linear cosmological gravitomagnetism into
a form showing the close correspondence with the laws of ordinary magnetism.
Our results, valid for any equation of state for cosmological matter, are: 1)
The dragging of a gyroscope axis by rotational perturbations of matter beyond
the Hubble-dot radius from the gyroscope is exponentially suppressed, where dot
is the derivative with respect to cosmic time. 2) If the perturbation of matter
is a homogeneous rotation inside some radius around a gyroscope, then exact
dragging of the gyroscope axis by the rotational perturbation is reached
exponentially fast as the rotation radius grows beyond the H-dot radius. 3) For
the most general linear cosmological perturbations the time-evolution of all
gyroscope spin axes exactly follow a weighted average of the energy currents of
cosmological matter. The weight function is the same as in Ampere's law except
that the inverse square law is replaced by the Yukawa force with the Hubble-dot
cutoff. Our results demonstrate (in first order perturbation theory for FRW
cosmologies with k = 0) the validity of Mach's hypothesis that axes of local
non-rotating frames precisely follow an average of the motion of cosmic matter.Comment: 18 pages, 1 figure. Comments and references adde
On the interaction of a single-photon wave packet with an excited atom
The interaction of a single-photon wave packet with an initially excited
two-level atom in free space is studied in semiclassical and quantum
approaches. It is shown that the final state of the field does not contain
doubly occupied modes. The process of the atom's transition to the ground state
may be accelerated, decelerated or even reversed by the incoming photon,
depending on parameters. The spectrum of emitted radiation is close to the sum
of the spectrum of the incoming single-photon wave packet and the natural line
shape, with small and complicated deviations.Comment: 17 pages, 5 figure
New two-sided bound on the isotropic Lorentz-violating parameter of modified Maxwell theory
There is a unique Lorentz-violating modification of the Maxwell theory of
photons, which maintains gauge invariance, CPT, and renormalizability.
Restricting the modified-Maxwell theory to the isotropic sector and adding a
standard spin-one-half Dirac particle p^\pm with minimal coupling to the
nonstandard photon \widetilde{\gamma}, the resulting
modified-quantum-electrodynamics model involves a single dimensionless
"deformation parameter," \widetilde{\kappa}_{tr}. The exact tree-level decay
rates for two processes have been calculated: vacuum Cherenkov radiation p^\pm
\to p^\pm \widetilde{\gamma} for the case of positive \widetilde{\kappa}_{tr}
and photon decay \widetilde{\gamma} \to p^+ p^- for the case of negative
\widetilde{\kappa}_{tr}. From the inferred absence of these decays for a
particular high-quality ultrahigh-energy-cosmic-ray event detected at the
Pierre Auger Observatory and an excess of TeV gamma-ray events observed by the
High Energy Stereoscopic System telescopes, a two-sided bound on
\widetilde{\kappa}_{tr} is obtained, which improves by eight orders of
magnitude upon the best direct laboratory bound. The implications of this
result are briefly discussed.Comment: 18 pages, v5: published version in preprint styl
Gravitation, electromagnetism and the cosmological constant in purely affine gravity
The Eddington Lagrangian in the purely affine formulation of general
relativity generates the Einstein equations with the cosmological constant. The
Ferraris-Kijowski purely affine Lagrangian for the electromagnetic field, which
has the form of the Maxwell Lagrangian with the metric tensor replaced by the
symmetrized Ricci tensor, is dynamically equivalent to the Einstein-Maxwell
Lagrangian in the metric formulation. We show that the sum of the two affine
Lagrangians is dynamically inequivalent to the sum of the analogous Lagrangians
in the metric-affine/metric formulation. We also show that such a construction
is valid only for weak electromagnetic fields. Therefore the purely affine
formulation that combines gravitation, electromagnetism and the cosmological
constant cannot be a simple sum of terms corresponding to separate fields.
Consequently, this formulation of electromagnetism seems to be unphysical,
unlike the purely metric and metric-affine pictures, unless the electromagnetic
field couples to the cosmological constant.Comment: 14 pages, extended and combined with gr-qc/0701176; published versio
On the nonsymmetric purely affine gravity
We review the vacuum purely affine gravity with the nonsymmetric connection
and metric. We also examine dynamical effects of the second Ricci tensor and
covariant second-rank tensors constructed from the torsion tensor in the
gravitational Lagrangian.Comment: 15 pages; published versio
The Electrostatics of Einstein's Unified Field Theory
When sources are added at their right-hand sides, and g_{(ik)} is a priori
assumed to be the metric, the equations of Einstein's Hermitian theory of
relativity were shown to allow for an exact solution that describes the general
electrostatic field of n point charges. Moreover, the injunction of spherical
symmetry of g_{(ik)} in the infinitesimal neighbourhood of each of the charges
was proved to yield the equilibrium conditions of the n charges in keeping with
ordinary electrostatics. The tensor g_{(ik)}, however, cannot be the metric of
the theory, since it enters neither the eikonal equation nor the equation of
motion of uncharged test particles. A physically correct metric that rules both
the behaviour of wave fronts and of uncharged matter is the one indicated by
H\'ely. In the present paper it is shown how the electrostatic solution
predicts the structure of the n charged particles and their mutual positions of
electrostatic equilibrium when H\'ely's physically correct metric is adopted.Comment: 15 pages. Misprints corrected. To appear in General Relativity and
Gravitatio
Irreducible decomposition of Gaussian distributions and the spectrum of black-body radiation
It is shown that the energy of a mode of a classical chaotic field, following
the continuous exponential distribution as a classical random variable, can be
uniquely decomposed into a sum of its fractional part and of its integer part.
The integer part is a discrete random variable (we call it Planck variable)
whose distribution is just the Bose distribution yielding the Planck law of
black-body radiation. The fractional part is the dark part (we call is dark
variable) with a continuous distribution, which is, of course, not observed in
the experiments. It is proved that the Bose distribution is infinitely
divisible, and the irreducible decomposition of it is given. The Planck
variable can be decomposed into an infinite sum of independent binary random
variables representing the binary photons (more accurately photo-molecules or
photo-multiplets) of energies 2^s*h*nu with s=0,1,2... . These binary photons
follow the Fermi statistics. Consequently, the black-body radiation can be
viewed as a mixture of statistically and thermodynamically independent fermion
gases consisting of binary photons. The binary photons give a natural tool for
the dyadic expansion of arbitrary (but not coherent) ordinary photon
excitations. It is shown that the binary photons have wave-particle
fluctuations of fermions. These fluctuations combine to give the wave-particle
fluctuations of the original bosonic photons expressed by the Einstein
fluctuation formula.Comment: 29 page
Einstein's fluctuation formula. A historical overview
A historical overview is given on the basic results which appeared by the
year 1926 concerning Einstein's fluctuation formula of black-body radiation, in
the context of light-quanta and wave-particle duality. On the basis of the
original publications (from Planck's derivation of the black-body spectrum and
Einstein's introduction of the photons up to the results of Born, Heisenberg
and Jordan on the quantization of a continuum) a comparative study is presented
on the first line of thoughts that led to the concept of quanta. The nature of
the particle-like fluctuations and the wave-like fluctuations are analysed by
using several approaches. With the help of the classical probability theory, it
is shown that the infinite divisibility of the Bose distribution leads to the
new concept of classical poissonian photo-multiplets or to the binary
photo-multiplets of fermionic character. As an application, Einstein's
fluctuation formula is derived as a sum of fermion type fluctuations of the
binary photo-multiplets.Comment: 34 page
Quantum Mechanical Carrier of the Imprints of Gravitation
We exhibit a purely quantum mechanical carrier of the imprints of gravitation
by identifying for a relativistic system a property which (i) is independent of
its mass and (ii) expresses the Poincare invariance of spacetime in the absence
of gravitation. This carrier consists of the phase and amplitude correlations
of waves in oppositely accelerating frames. These correlations are expressed as
a Klein-Gordon-equation-determined vector field whose components are the
``Planckian power'' and the ``r.m.s. thermal fluctuation'' spectra. The
imprints themselves are deviations away from this vector field.Comment: 8 pages, RevTex. Html version of this and related papers on
accelerated frames available at http://www.math.ohio-state.edu/~gerlac
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