11,018 research outputs found
Plane Gravitational Radiation from Neutrinos Source with Kalb-Ramond Coupling
In this work, we propose a model based on a non-minimal coupling of neutrinos
to a Kalb-Ramond field. The latter is taken as a possible source for
gravitational radiation. As an immediate illustration of this system, we have
studied the case where gravitational (plane) wave solutions behave as damped
harmonic oscillators.Comment: Presented at 7th Alexander Friedmann International Seminar on
Gravitation and Cosmology, Joao Pessoa, Brazil, 29-05 Jul 200
Correlated versus Uncorrelated Stripe Pinning: the Roles of Nd and Zn Co-Doping
We investigate the stripe pinning produced by Nd and Zn co-dopants in
cuprates via a renormalization group approach. The two dopants play
fundamentally different roles in the pinning process. While Nd induces a
correlated pinning potential that traps the stripes in a flat phase and
suppresses fluctuations, Zn pins the stripes in a disordered manner and
promotes line meandering. We obtain the zero temperature phase diagram and
compare our results with neutron scattering data. A good agreement is found
between theory and experiment.Comment: To appear at the proceedings of the LLD2K Conference Tsukuba, July
2000, Japan. 4 pages, 2 figure
Wave polarizations for a beam-like gravitational wave in quadratic curvature gravity
We compute analytically the tidal field and polarizations of an exact
gravitational wave generated by a cylindrical beam of null matter of finite
width and length in quadratic curvature gravity. We propose that this wave can
represent the gravitational wave that keep up with the high energy photons
produced in a gamma ray burst (GRB) source.Comment: 5 pages, 3 figures, minor corrections, to appear in CQ
Dilatonic, Current-Carrying Cosmic String
We study the implications of a scalar-tensorial gravity for the metric of an
isolated self-gravitating superconducting cosmic string. These modifications
are induced by an arbitrary coupling of a massless scalar field to the usual
tensorial field in the gravitational Lagrangian. We derive the metric in the
weak-field approximation and we analyse the behaviour of light in this
spacetime. We end with some discussions.Comment: 12 pp, Latex, no figures, based on a talk given by M. E. X. Guimaraes
at the COSMO 99, 27/9 to 02/10/99, ICTP, Trieste, I
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