7,078 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.
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
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
Tracing high density gas in M 82 and NGC 4038
We present the first detection of CS in the Antennae galaxies towards the NGC
4038 nucleus, as well as the first detections of two high-J (5-4 and 7-6) CS
lines in the center of M 82. The CS(7-6) line in M 82 shows a profile that is
surprisingly different to those of other low-J CS transitions we observed. This
implies the presence of a separate, denser and warmer molecular gas component.
The derived physical properties and the likely location of the CS(7-6) emission
suggests an association with the supershell in the centre of M 82.Comment: 10 pages, 3 figures, ApJ Letter - ACCEPTE
Anisotropic thermal magnetoresistance for an active control of radiative heat transfer
We predict a huge anisotropic thermal magnetoresistance (ATMR) in the
near-field radiative heat transfer between magneto-optical particles when the
direction of an external magnetic field is changed with respect to the heat
current direction. We illustrate this effect with the case of two InSb
spherical particles where we find that the ATMR amplitude can reach values of
up to 800% for a magnetic field of 5 T, which is many orders of magnitude
larger than its spintronic analogue in electronic devices. This thermomagnetic
effect could find broad applications in the fields of ultrafast thermal
management as well as magnetic and thermal remote sensing.Comment: 6 pages, 4 figure
- âŠ