3,346 research outputs found
New Curved Spacetime Dirac Equations - On the Anomalous Gyromagnetic Ratio
I propose three new curved spacetime versions of the Dirac Equation. These
equations have been developed mainly to try and account in a natural way for
the observed anomalous gyromagnetic ratio of Fermions. The derived equations
suggest that particles including the Electron which is thought to be a point
particle do have a finite spatial size which is the reason for the observed
anomalous gyromagnetic ratio. A serendipitous result of the theory, is that,
two of the equation exhibits an asymmetry in their positive and negative energy
solutions the first suggestion of which is clear that a solution to the problem
as to why the Electron and Muon - despite their acute similarities - exhibit an
asymmetry in their mass is possible. The Mourn is often thought as an Electron
in a higher energy state. Another of the consequences of three equations
emanating from the asymmetric serendipity of the energy solutions of two of
these equations, is that, an explanation as to why Leptons exhibit a three
stage mass hierarchy is possible.Comment: 8 pages, errors corrected, final form of the paper and no further
changes to be made. Accepted in the Foundations of Physics Journa
Gauge invariant Lagrangian for non-Abelian tensor gauge fields of fourth rank
Using generalized field strength tensors for non-Abelian tensor gauge fields
one can explicitly construct all possible Lorentz invariant quadratic forms for
rank-4 non-Abelian tensor gauge fields and demonstrate that there exist only
two linear combinations of them which form a gauge invariant Lagrangian.
Together with the previous construction of independent gauge invariant forms
for rank-2 and rank-3 tensor gauge fields this construction proves the
uniqueness of early proposed general Lagrangian up to rank-4 tensor fields.
Expression for the coefficients of the general Lagrangian is presented in a
compact form.Comment: 27 pages, LaTex fil
Area-preserving Structure and Anomalies in 1+1-dimensional Quantum Gravity
We investigate the gauge-independent Hamiltonian formulation and the
anomalous Ward identities of a matter-induced 1+1-dimensional gravity theory
invariant under Weyl transformations and area-preserving diffeomorphisms, and
compare the results to the ones for the conventional diffeomorphism-invariant
theory. We find that, in spite of several technical differences encountered in
the analysis, the two theories are essentially equivalent.Comment: 9 pages, LaTe
Nonlinear QED and Physical Lorentz Invariance
The spontaneous breakdown of 4-dimensional Lorentz invariance in the
framework of QED with the nonlinear vector potential constraint
A_{\mu}^{2}=M^{2}(where M is a proposed scale of the Lorentz violation) is
shown to manifest itself only as some noncovariant gauge choice in the
otherwise gauge invariant (and Lorentz invariant) electromagnetic theory. All
the contributions to the photon-photon, photon-fermion and fermion-fermion
interactions violating the physical Lorentz invariance happen to be exactly
cancelled with each other in the manner observed by Nambu a long ago for the
simplest tree-order diagrams - the fact which we extend now to the one-loop
approximation and for both the time-like (M^{2}>0) and space-like (M^{2}<0)
Lorentz violation. The way how to reach the physical breaking of the Lorentz
invariance in the pure QED case taken in the flat Minkowskian space-time is
also discussed in some detail.Comment: 16 pages, 2 Postscript figures to be published in Phys. Rev.
Dirac reduction revisited
The procedure of Dirac reduction of Poisson operators on submanifolds is
discussed within a particularly useful special realization of the general
Marsden-Ratiu reduction procedure. The Dirac classification of constraints on
'first-class' constraints and 'second-class' constraints is reexamined.Comment: This is a revised version of an article published in J. Nonlinear
Math. Phys. vol. 10, No. 4, (2003), 451-46
Recent Results Regarding Affine Quantum Gravity
Recent progress in the quantization of nonrenormalizable scalar fields has
found that a suitable non-classical modification of the ground state wave
function leads to a result that eliminates term-by-term divergences that arise
in a conventional perturbation analysis. After a brief review of both the
scalar field story and the affine quantum gravity program, examination of the
procedures used in the latter surprisingly shows an analogous formulation which
already implies that affine quantum gravity is not plagued by divergences that
arise in a standard perturbation study. Additionally, guided by the projection
operator method to deal with quantum constraints, trial reproducing kernels are
introduced that satisfy the diffeomorphism constraints. Furthermore, it is
argued that the trial reproducing kernels for the diffeomorphism constraints
may also satisfy the Hamiltonian constraint as well.Comment: 32 pages, new features in this alternative approach to quantize
gravity, minor typos plus an improved argument in Sec. 9 suggested by Karel
Kucha
Physical constants and the Gurzadyan-Xue formula for the dark energy
We consider cosmological implications of the formula for the dark energy
density derived by Gurzadyan and Xue which predicts a value fitting the
observational one. Cosmological models with varying by time physical constants,
namely, speed of light and gravitational constant and/or their combinations,
are considered. In one of the models, for example, vacuum energy density
induces effective negative curvature, while another one has an unusual
asymptotic. This analysis also explicitely rises the issue of the meaning and
content of physical units and constants in cosmological context.Comment: version corrected to match the one to appear in Modern Physics
Letters
On-shell consistency of the Rarita-Schwinger field formulation
We prove that any bilinear coupling of a massive spin-3/2 field can be
brought into a gauge invariant form suggested by Pascalutsa by means of a
non-linear field redefinition. The corresponding field transformation is given
explicitly in a closed form and the implications for chiral effective field
theory with explicit Delta (1232) isobar degrees of freedom are discussed.Comment: 9 pages, 1 figur
Topological insulator and the Dirac equation
We present a general description of topological insulators from the point of
view of Dirac equations. The Z_{2} index for the Dirac equation is always zero,
and thus the Dirac equation is topologically trivial. After the quadratic B
term in momentum is introduced to correct the mass term m or the band gap of
the Dirac equation, the Z_{2} index is modified as 1 for mB>0 and 0 for mB<0.
For a fixed B there exists a topological quantum phase transition from a
topologically trivial system to a non-trivial one system when the sign of mass
m changes. A series of solutions near the boundary in the modified Dirac
equation are obtained, which is characteristic of topological insulator. From
the solutions of the bound states and the Z_{2} index we establish a relation
between the Dirac equation and topological insulators.Comment: 9 pages, published versio
General Very Special Relativity is Finsler Geometry
We ask whether Cohen and Glashow's Very Special Relativity model for Lorentz
violation might be modified, perhaps by quantum corrections, possibly producing
a curved spacetime with a cosmological constant. We show that its symmetry
group ISIM(2) does admit a 2-parameter family of continuous deformations, but
none of these give rise to non-commutative translations analogous to those of
the de Sitter deformation of the Poincar\'e group: spacetime remains flat. Only
a 1-parameter family DISIM_b(2) of deformations of SIM(2) is physically
acceptable. Since this could arise through quantum corrections, its
implications for tests of Lorentz violations via the Cohen-Glashow proposal
should be taken into account. The Lorentz-violating point particle action
invariant under DISIM_b(2) is of Finsler type, for which the line element is
homogeneous of degree 1 in displacements, but anisotropic. We derive
DISIM_b(2)-invariant wave equations for particles of spins 0, 1/2 and 1. The
experimental bound, , raises the question ``Why is the
dimensionless constant so small in Very Special Relativity?''Comment: 4 pages, minor corrections, references adde
- …