7 research outputs found
Non-supersymmetric Black Holes and Topological Strings
We study non-supersymmetric, extremal 4 dimensional black holes which arise
upon compactification of type II superstrings on Calabi-Yau threefolds. We
propose a generalization of the OSV conjecture for higher derivative
corrections to the non-supersymmetric black hole entropy, in terms of the one
parameter refinement of topological string introduced by Nekrasov. We also
study the attractor mechanism for non-supersymmetric black holes and show how
the inverse problem of fixing charges in terms of the attractor value of CY
moduli can be explicitly solved.Comment: 47 pages, harvmac. v2: footnote(4) expanded, references adde
Lectures on on Black Holes, Topological Strings and Quantum Attractors (2.0)
In these lecture notes, we review some recent developments on the relation
between the macroscopic entropy of four-dimensional BPS black holes and the
microscopic counting of states, beyond the thermodynamical, large charge limit.
After a brief overview of charged black holes in supergravity and string
theory, we give an extensive introduction to special and very special geometry,
attractor flows and topological string theory, including holomorphic anomalies.
We then expose the Ooguri-Strominger-Vafa (OSV) conjecture which relates
microscopic degeneracies to the topological string amplitude, and review
precision tests of this formula on ``small'' black holes. Finally, motivated by
a holographic interpretation of the OSV conjecture, we give a systematic
approach to the radial quantization of BPS black holes (i.e. quantum
attractors). This suggests the existence of a one-parameter generalization of
the topological string amplitude, and provides a general framework for
constructing automorphic partition functions for black hole degeneracies in
theories with sufficient degree of symmetry.Comment: 103 pages, 8 figures, 21 exercises, uses JHEP3.cls; v5: important
upgrade, prepared for the proceedings of Frascati School on Attractor
Mechanism; Sec 7 was largely rewritten to incorporate recent progress; more
figures, more refs, and minor changes in abstract and introductio
Can we predict for the Non-SUSY sector of the Landscape ?
We propose a new selection criteria for predicting the most probable
wavefunction of the universe that propagates on the string landscape
background, by studying its dynamics from a quantum cosmology view. Previously
we applied this proposal to the sector of the landscape. In this work
the dynamic selection criterion is applied to the investigation of the
non- sector.In the absence of detailed information about its structure,
it is assumed that this sector has a stochastic distribution of vacua
energies.The calculation of a distribution probability for the cosmological
constants , obtained from the density of states ,
indicates that the most probable wavefunction is peaked around universes with
zero . In contrast to the {\it extended wavefunction} solutions
found for the sector with -vacua and peaked around
, wavefunctions residing on the non-
sector exhibit {\it Anderson localization}.Although minisuperspace is a limited
approach it presently provides a dynamical quantum selection rule for the most
probable vacua solution from the landscape.Comment: 6 pages, 1 figur
Brane Dynamics and Gauge Theory
We review some aspects of the interplay between the dynamics of branes in
string theory and the classical and quantum physics of gauge theories with
different numbers of supersymmetries in various dimensions.Comment: 291 pages, 52 figures; expanded introduction and minor change
RR photons
Type II string compactifications to 4d generically contain massless Ramond-Ramond U(1) gauge symmetries. However there is no massless matter charged under these U(1)'s, which makes a priori difficult to measure any physical consequences of their existence. There is however a window of opportunity if these RR U(1)'s mix with the hypercharge (hence with the photon). In this paper we study in detail different avenues by which bosons may mix with D-brane U(1)'s. We concentrate on Type IIA orientifolds and their M-theory lift, and provide geometric criteria for the existence of such mixing, which may occur either via standard kinetic mixing or via the mass terms induced by St\"uckelberg couplings. The latter case is particularly interesting, and appears whenever D-branes wrap torsional -cycles in the compactification manifold. We also show that in the presence of torsional cycles discrete gauge symmetries and Aharanov-Bohm strings and particles appear in the 4d effective action, and that type IIA St\"uckelberg couplings can be understood in terms of torsional (co)homology in M-theory. We provide examples of Type IIA Calabi-Yau orientifolds in which the required torsional cycles exist and kinetic mixing induced by mass mixing is present. We discuss some phenomenological consequences of our findings. In particular, we find that mass mixing may induce corrections relevant for hypercharge gauge coupling unification in F-theory SU(5) GUT's