8 research outputs found
Emission Spectrum of Fundamental Strings: An Algebraic Approach
We formulate a linear difference equation which yields averaged
semi-inclusive decay rates for arbitrary, not necessarily large, values of the
masses. We show that the rates for decays M \to m+\M' of typical heavy open
strings are independent of the masses and , and compute the ``mass
deffect''. For closed strings we find decay rates proportional to , where is the reduced mass of the decy products. Our
method yields exact interaction rates valid for all mass ranges and may provide
a fully microscopic basis, not limited to the long string approximation, for
the interactions in the Boltzmann equation approach to hot string gases.Comment: 35 pages, 3 figure
Large N limit of Extremal Non-supersymmetric Black Holes
The large N limit of extremal non-supersymmetric Type-I five-dimensional
string black holes is studied from the point of view of D-branes.
We find that the agreement between the D-brane and the black-hole picture is
due to an asymptotic restoration of supersymmetry in the large limit in
which both pictures are compared.
In that limit Type-I string perturbation theory is effectively embedded into
a Type-IIB perturbation theory with unbroken supersymmetric charges whose
presence guarantees the non-renormalization of mass and entropy as the
effective couplings are increased. In this vein, we also study the near-horizon
geometry of the Type-I black hole using D5-brane probes to find that the low
energy effective action for the probe is identical to the corresponding one in
the auxiliary Type-IIB theory in the large N limit.Comment: 25 pages, harvmac, typos corrected and references adde
Models of electron transport in single layer graphene
The main features of the conductivity of doped single layer graphene are
analyzed, and models for different scattering mechanisms are presented.Comment: 15 pages. Submitted to the Proceedings of the ULTI symposium on
Quantum Phenomena and Devices at Low Temperatures, Espoo, Finland, to be
published in the Journ. of Low. Temp. Phy
Recommended from our members
Signatures of Sixfold Degenerate Exotic Fermions in a Superconducting Metal PdSb2
Multifold degenerate points in the electronic structure of metals lead to exotic behaviors. These range from twofold and fourfold degenerate Weyl and Dirac points, respectively, to sixfold and eightfold degenerate points that are predicted to give rise, under modest magnetic fields or strain, to topological semimetallic behaviors. The present study shows that the nonsymmorphic compound PdSb2 hosts six-component fermions or sextuplets. Using angle-resolved photoemission spectroscopy, crossing points formed by three twofold degenerate parabolic bands are directly observed at the corner of the Brillouin zone. The group theory analysis proves that under weak spin–orbit interaction, a band inversion occurs. © 2020 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei