3,485 research outputs found
Influence of trigonal warping on interference effects in bilayer graphene
Bilayer graphene (two coupled graphitic monolayers arranged according to Bernal stacking) is a two-dimensional gapless semiconductor with a peculiar electronic spectrum different from the Dirac spectrum in the monolayer material. In particular, the electronic Fermi line in each of its valleys has a strong p -> -p asymmetry due to trigonal warping, which suppresses the weak localization effect. We show that weak localization in bilayer graphene may be present only in devices with pronounced intervalley scattering, and we evaluate the corresponding magnetoresistance
Uninformed sacrifice: evidence against long-range alarm transmission in foraging ants exposed to a localized perturbation
It is well stablished that danger information can be transmitted by ants
through relatively small distances, provoking either a state of alarm when they
move away from potentially dangerous stimulus, or charge toward it
aggressively. There is almost no knowledge if danger information can be
transmitted along large distances. In this paper, we perturb leaf cutting ants
of the species Atta insularis while they forage in their natural evioronment at
a certain point of the foraging line, so ants make a "U" turn to escape from
the danger zone and go back to the nest. Our results strongly suggest that
those ants do not transmit "danger information" to other nestmates marching
towards the danger area. The individualistic behavior of the ants returning
from the danger zone results in a depression of the foraging activity due to
the systematic sacrifice of non-informed individuals.Comment: 5 pages, 2 figure
RANDOM MATRIX THEORY APPROACH TO THE INTENSITY DISTRIBUTIONS OF WAVES PROPAGATING IN A RANDOM MEDIUM
Statistical properties of coherent radiation propagating in a quasi - 1D
random media is studied in the framework of random matrix theory. Distribution
functions for the total transmission coefficient and the angular transmission
coefficient are obtained.Comment: 8 pages, latex, no figures. Submitted to Phys.Rev.
Differential identities for parametric correlation functions in disordered systems
Copyright © 2008 The American Physical Society.We derive a family of differential identities for parametric correlation functions in disordered systems by casting them as first- or second-order Ward identities of an associated matrix model. We show that this approach allows for a systematic classification of such identities, and provides a template for deriving higher-order results. We also reestablish and generalize some identities of this type which had been derived previously using a different method
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