10,565 research outputs found
Linear perturbations of spatially locally homogeneous spacetimes
Methods and properties regarding the linear perturbations are discussed for
some spatially closed (vacuum) solutions of Einstein's equation. The main focus
is on two kinds of spatially locally homogeneous solution; one is the Bianchi
III (Thurston's H^2 x R) type, while the other is the Bianchi II (Thurston's
Nil) type. With a brief summary of previous results on the Bianchi III
perturbations, asymptotic solutions for the gauge-invariant variables for the
Bianchi III are shown, with which (in)stability of the background solution is
also examined. The issue of linear stability for a Bianchi II solution is still
an open problem. To approach it, appropriate eigenfunctions are presented for
an explicitly compactified Bianchi II manifold and based on that, some field
equations on the Bianchi II background spacetime are studied. Differences
between perturbation analyses for Bianchi class B (to which Bianchi III
belongs) and class A (to which Bianchi II belongs) are stressed for an
intention to be helpful for applications to other models.Comment: Eq.(2.2) and Eq.(3.1) swapped. Errata to the (yet-to-be) published
version attached. 16 pages, to appear in Contemporary Mathematics, AM
Prediction on CP Violation in Long Baseline Neutrino Oscillation Experiments
We predict CP violation in the long baseline accelerator experiments taking
into consideration the recent LSND data and the atmospheric neutrino data. The
estimated upper bound of CP violation is 0.006, which may be observable in the
long baseline accelerator experiments. It is found that the upper bound
increases to 0.01 if the LSND data is excluded. The matter effect, which is not
CP invariant, is found to be very small in the case we consider.Comment: 23 pages, LaTex file, 4 figures included using epsfig fig.3 and 4 are
added. To be published in PT
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