22 research outputs found
Quaternionic (super)twistors extensions and general superspaces
In a attempt to treat a supergravity as a tensor representation, the
4-dimensional N-extended quaternionic superspaces are constructed from the
(diffeomorphyc)graded extension of the ordinary Penrose-twistor formulation,
performed in a previous work of the authors[14], with N = p + k: These
quaternionic superspaces have 4 + k (N - k) even-quaternionic coordinates and
4N odd- quaternionic coordinates where each coordinate is a quaternion composed
by four C-felds (bosons and fermions respectively). The fields content as the
dimensionality (even and odd sectors) of these superspaces are given and
exemplified by selected physical cases. In this case the number of felds of the
supergravity is determined by the number of components of the tensor
representation of the 4-dimensional N-extended quaternionic superspaces. The
role of tensorial central charges for any N even USp (N) = Sp (N;HC) \ U (N;HC)
is elucidated from this theoretical context.Comment: To be published in the IJGMMP 2016, corrected version, 16 pages
without figure
Quaternionic structures, supertwistors and fundamental superspaces
Superspace is considered as space of parameters of the supercoherent states
defining the basis for oscillator-like unitary irreducible representations of
the generalized superconformal group SU(2m,2n/2N) in the field of quaternions
H. The specific construction contains naturally the supertwistor one of the
previous work by Litov and Pervushin [1] and it is shown that in the case of
extended supersymmetry such an approach leads to the separation of a class of
superspaces and and its groups of motion. We briefly discuss this particular
extension to the domain of quaternionic superspaces as nonlinear realization of
some kind of the affine and the superconformal groups with the final end to
include also the gravitational field[6] (this last possibility to include
gravitation, can be realized on the basis of the reference[12] where the coset
((Sp(8))/(SL(4R)))~((SU(2,2))/(SL(2C)))was used in the non supersymmetric
case). It is shown that this quaternionic construction avoid some
unconsistencies appearing at the level of the generators of the superalgebras
(for specific values of p and q; p+q=N) in the twistor one.Comment: Improved version. Accepted in the International Journal of
Geometrical Methods in Modern Physics (IJGMMP)12 pages, no figures. In
memoriam of Professor Boris Moyseevich Zupnik, pioneer of the development of
supersymmetry, group theory and modern mathematical methods in theoretical
physic
Description of Supernova Data in Conformal Cosmology without Cosmological Constant
We consider cosmological consequences of a conformal invariant formulation of
Einstein's General Relativity where instead of the scale factor of the spatial
metrics in the action functional a massless scalar (dilaton) field occurs which
scales all masses including the Planck mass. Instead of the expansion of the
universe we get the Hoyle-Narlikar type of mass evolution, where the
temperature history of the universe is replaced by the mass history. We show
that this conformal invariant cosmological model gives a satisfactory
description of the new supernova Ia data for the effective magnitude - redshift
relation without a cosmological constant and make a prediction for the
high-redshift behavior which deviates from that of standard cosmology for
.Comment: 13 pages, 1 figure, includes discussion of SN1997ff, text revise
Conformal Cosmological Model Parameters with Distant SNe Ia Data: "gold" and "silver"
Assuming that supernovae type Ia (SNe Ia) are standard candles one could use
them to test cosmological theories. The Hubble Space Telescope team analyzed
186 SNe Ia\cite{Riess_04} to test the Standard Cosmological model (SC)
associated with expanded lengths in the Universe and evaluate its parameters.
We use the same sample to determine parameters of Conformal Cosmological model
(CC) with relative reference units of intervals, so that conformal quantities
of General Relativity are interpreted as observables. We concluded, that really
the test is extremely useful and allows to evaluate parameters of the model.
From a formal statistical point of view the best fit of the CC model is almost
the same quality approximation as the best fit of SC model with
. As it was noted earlier, for CC models, a
rigid matter component could substitute the -term (or quintessence)
existing in the SC model. We note that a free massless scalar field can
generate such a rigid matter. We describe results of our analysis for more
recent "gold" data (for 192 SNe Ia).Comment: 13 pages, 4 figures, accepted in International Journal of Modern
Physics
Conformal and Affine Hamiltonian Dynamics of General Relativity
The Hamiltonian approach to the General Relativity is formulated as a joint
nonlinear realization of conformal and affine symmetries by means of the Dirac
scalar dilaton and the Maurer-Cartan forms. The dominance of the Casimir vacuum
energy of physical fields provides a good description of the type Ia supernova
luminosity distance--redshift relation. Introducing the uncertainty principle
at the Planck's epoch within our model, we obtain the hierarchy of the Universe
energy scales, which is supported by the observational data. We found that the
invariance of the Maurer-Cartan forms with respect to the general coordinate
transformation yields a single-component strong gravitational waves. The
Hamiltonian dynamics of the model describes the effect of an intensive vacuum
creation of gravitons and the minimal coupling scalar (Higgs) bosons in the
Early Universe.Comment: 37 pages, version submitted to Gen. Rel. Gra