4,145 research outputs found
Static plane symmetric relativistic fluids and empty repelling singular boundaries
We present a detailed analysis of the general exact solution of Einstein's
equation corresponding to a static and plane symmetric distribution of matter
with density proportional to pressure. We study the geodesics in it and we show
that this simple spacetime exhibits very curious properties. In particular, it
has a free of matter repelling singular boundary and all geodesics bounce off
it.Comment: 9 pages, 1 figure, accepted for publication in Classical and Quantum
Gravit
On spectral types of semialgebraic sets
In this work we prove that a semialgebraic set is
determined (up to a semialgebraic homeomorphism) by its ring
of (continuous) semialgebraic functions while its ring of
(continuous) bounded semialgebraic functions only determines besides a
distinguished finite subset . In addition it holds that the
rings and are isomorphic if and only if
is compact. On the other hand, their respective maximal spectra
and endowed with the Zariski topology are always homeomorphic and
topologically classify a `large piece' of . The proof of this fact requires
a careful analysis of the points of the remainder associated with formal paths.Comment: 22 page
Noncommutative quantum mechanics and the Aharonov-Casher effect
In this work a new method is developed to investigate the Aharonov-Casher
effect in a noncommutative space. It is shown that the holonomy receives
non-trivial kinematical corrections.Comment: 8 pages, Plain Tex, to appear in Eur. Phys. J.
On gauge invariant regularization of fermion currents
We compare Schwinger and complex powers methods to construct regularized
fermion currents. We show that although both of them are gauge invariant they
not always yield the same result.Comment: 10 pages, 1 figur
Duality and bosonization in Schwinger-Keldysh formulation
We present a path-integral bosonization approach for systems out of
equilibrium based on a duality transformation of the original Dirac fermion
theory combined with the Schwinger-Keldysh time closed contour technique, to
handle the non-equilibrium situation. The duality approach to bosonization that
we present is valid for space-time dimensions leading for to
exact results. In this last case we present the bosonization rules for fermion
currents, calculate current-current correlation functions and establish the
connection between the fermionic and bosonic distribution functions in a
generic, nonequilibrium situation.Comment: 16 pages, 1 figur
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