9,619 research outputs found
Higher dimensional VSI spacetimes and supergravity
We present the explicit form of higher dimensional VSI spacetimes in
arbitrary number of dimensions. We discuss briefly the VSI's in the context of
supergravity/strings.Comment: 3 pages, to be published in the Proceedings of the Eleventh Marcel
Grossmann Meeting on General Relativit
Supergravity solutions with constant scalar invariants
We study a class of constant scalar invariant (CSI) spacetimes, which belong
to the higher-dimensional Kundt class, that are solutions of supergravity. We
review the known CSI supergravity solutions in this class and we explicitly
present a number of new exact CSI supergravity solutions, some of which are
Einstein.Comment: 12 pages; to appear in IJMP
A note on BRST quantization of SU(2) Yang-Mills mechanics
The quantization of SU(2) Yang-Mills theory reduced to 0+1 space-time
dimensions is performed in the BRST framework. We show that in the unitary
gauge the BRST procedure has difficulties which can be solved by
introduction of additional singlet ghost variables. In the Lorenz gauge
one has additional unphysical degrees of freedom, but the BRST
quantization is free of the problems in the unitary gauge.Comment: 17 page
Higher dimensional VSI spacetimes
We present the explicit metric forms for higher dimensional vanishing scalar
invariant (VSI) Lorentzian spacetimes. We note that all of the VSI spacetimes
belong to the higher dimensional Kundt class. We determine all of the VSI
spacetimes which admit a covariantly constant null vector, and we note that in
general in higher dimensions these spacetimes are of Ricci type III and Weyl
type III. The Ricci type N subclass is related to the chiral null models and
includes the relativistic gyratons and the higher dimensional pp-wave
spacetimes. The spacetimes under investigation are of particular interest since
they are solutions of supergravity or superstring theory.Comment: 14 pages, changes in second paragraph of the discussio
Global Linear Complexity Analysis of Filter Keystream Generators
An efficient algorithm for computing lower bounds on the global linear
complexity of nonlinearly filtered PN-sequences is presented. The technique
here developed is based exclusively on the realization of bit wise logic
operations, which makes it appropriate for both software simulation and
hardware implementation. The present algorithm can be applied to any arbitrary
nonlinear function with a unique term of maximum order. Thus, the extent of its
application for different types of filter generators is quite broad.
Furthermore, emphasis is on the large lower bounds obtained that confirm the
exponential growth of the global linear complexity for the class of nonlinearly
filtered sequences
Extracting the top-quark running mass using +1-jet events produced at the Large Hadron Collider
We present the calculation of the next-to-leading order QCD corrections for
top-quark pair production in association with an additional jet at hadron
colliders, using the modified minimal subtraction scheme to renormalize the
top-quark mass. The results are compared to measurements at the Large Hadron
Collider run I. In particular, we determine the top-quark running mass from a
fit of the theoretical results presented here to the LHC data
Finsler pp-waves
In this work we present a Finslerian version of the well-known pp-waves,
which generalizes the very special relativity (VSR) line element. Our Finsler
pp-waves are an exact solution of Finslerian Einstein's equations in vacuum.Comment: 10 pages, minor corrections, references adde
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