8,509 research outputs found
Magnetic Field Effects on the Transport Properties of One-sided Rough Wires
We present a detailed numerical analysis of the effect of a magnetic field on
the transport properties of a `small-' one-sided surface disordered wire.
When time reversal symmetry is broken due to a magnetic field , we find a
strong increase with not only of the localization length but also of
the mean free path caused by boundary states. Despite this, the
universal relationship between and does hold. We also analyze the
conductance distribution at the metal-insulator crossover, finding a very good
agreement with Random Matrix Theory with two fluctuating channels within the
Circular Orthogonal(Unitary) Ensemble in absence(presence) of Comment: 5 pages, 4 figures, to appear in Phys. Rev.
Einstein constraints on a characteristic cone
We analyse the Cauchy problem on a characteristic cone, including its vertex,
for the Einstein equations in arbitrary dimensions. We use a wave map gauge,
solve the obtained constraints and show gauge conservation.Comment: 10 pages, to be published in the Proceedings of the 15th
International Conference on Waves and Stability in Continuous Media, held in
Palermo, 28th June to 1st July 200
A complete gauge-invariant formalism for arbitrary second-order perturbations of a Schwarzschild black hole
Using recently developed efficient symbolic manipulations tools, we present a
general gauge-invariant formalism to study arbitrary radiative
second-order perturbations of a Schwarzschild black hole. In particular, we
construct the second order Zerilli and Regge-Wheeler equations under the
presence of any two first-order modes, reconstruct the perturbed metric in
terms of the master scalars, and compute the radiated energy at null infinity.
The results of this paper enable systematic studies of generic second order
perturbations of the Schwarzschild spacetime. In particular, studies of
mode-mode coupling and non-linear effects in gravitational radiation, the
second-order stability of the Schwarzschild spacetime, or the geometry of the
black hole horizon.Comment: 14 page
Spinor calculus on 5-dimensional spacetimes
Penrose's spinor calculus of 4-dimensional Lorentzian geometry is extended to
the case of 5-dimensional Lorentzian geometry. Such fruitful ideas in Penrose's
spinor calculus as the spin covariant derivative, the curvature spinors or the
definition of the spin coefficients on a spin frame can be carried over to the
spinor calculus in 5-dimensional Lorentzian geometry. The algebraic and
differential properties of the curvature spinors are studied in detail and as
an application we extend the well-known 4-dimensional Newman-Penrose formalism
to a 5-dimensional spacetime.Comment: Convention mismatch and minor typos fixed. To appear in Journal of
Mathematical Physic
Cambios de la mineralogía de arcillas en el tránsito Paleoceno/Eoceno del dominio Maláguide (Zonas Internas Béticas, S.E. España)
El tránsito Paleoceno/Eoceno del Dominio Maláguide (manto superior y no metamorfizado de la Zona Interna Bética, sectores occidentales de la Cadena Alpina), está caracterizado por una discontinuidad asociada a una laguna estratigráfica, que afecta al Ilerdiense. Durante el paso del Paleoceno al Eoceno se han detectado cambios en el tipo de depósitos condicionados por la naturaleza de las áreas fuentes. Los medios sedimentarios marinos evolucionan de una plataforma mixta a otra carbonatada y los medios continentales cambian de condiciones fluviales a lacustres. El registro mineralógico encontrado en los sedimentos marinos ha permitido deducir variaciones relativas del nivel del mar, que se relacionarían con procesos tectónicos compresivos regionales. También se ha deducido un cambio climático desde un clima estacionalmente seco a otro tropical húmedo. Este cambio climático favoreció, en el medio marino, el cambio de las condiciones de productividad que pasaron de eutróficas, durante el Paleoceno, a oligotróficas durante el Eoceno.The Paleocene/Eocene transition in the Malaguide Domain, upper and unmetamorphosed nappe of the Internal Betic Zone (Western Alpine Belt), is characterized by a stratigraphic unconformity with a stratigraphic gap affecting the Ilerdian. Some depositional changes, conditioned by the nature of the source areas, were detected during the Paleocene/Eocene transition. The sedimentary marine environment evolved from a mixed platform to a carbonated platform, whereas in the continental realm a change from fluvial to lacustrine conditions took place. The mineralogical record found in marine sediments allowed the observation of a variation in the relative sea level curve due to regional compressive tectonic processes and a transition from a seasonally dry climate to a humid tropical climate. This transition favoured, in the marine environment, the change from eutrophic conditions during the Paleocene to oligotrophic conditions during the Eocene
Anderson localization in a periodic photonic lattice with a disordered boundary
We investigate experimentally the light evolution inside a two-dimensional
finite periodic array of weakly- coupled optical waveguides with a disordered
boundary. For a completely localized initial condition away from the surface,
we find that the disordered boundary induces an asymptotic localization in the
bulk, centered around the initial position of the input beam.Comment: 3 pages, 4 figure
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