38 research outputs found
Black holes as D3-branes on Calabi-Yau threefolds
We show how an extremal Reissner-Nordstrom black hole can be obtained by
wrapping a dyonic D3-brane on a Calabi-Yau manifold. In the orbifold limit
T^6/Z_3, we explicitly show the correspondence between the solution of the
supergravity equations of motion and the D-brane boundary state description of
such a black hole.Comment: 14 pages, LaTex, minor corrections, version to appear on Phys. Lett.
A Contour Integral Representation for the Dual Five-Point Function and a Symmetry of the Genus Four Surface in R6
The invention of the "dual resonance model" N-point functions BN motivated
the development of current string theory. The simplest of these models, the
four-point function B4, is the classical Euler Beta function. Many standard
methods of complex analysis in a single variable have been applied to elucidate
the properties of the Euler Beta function, leading, for example, to analytic
continuation formulas such as the contour-integral representation obtained by
Pochhammer in 1890. Here we explore the geometry underlying the dual five-point
function B5, the simplest generalization of the Euler Beta function. Analyzing
the B5 integrand leads to a polyhedral structure for the five-crosscap surface,
embedded in RP5, that has 12 pentagonal faces and a symmetry group of order 120
in PGL(6). We find a Pochhammer-like representation for B5 that is a contour
integral along a surface of genus five. The symmetric embedding of the
five-crosscap surface in RP5 is doubly covered by a symmetric embedding of the
surface of genus four in R6 that has a polyhedral structure with 24 pentagonal
faces and a symmetry group of order 240 in O(6). The methods appear
generalizable to all N, and the resulting structures seem to be related to
associahedra in arbitrary dimensions.Comment: 43 pages and 44 figure
Non-renormalization for planar Wess-Zumino model
Using a non-perturbative functional method, where the quantum fluctuations
are gradually set up,it is shown that the interaction of a N=1 Wess-Zumino
model in 2+1 dimensions does not get renormalized. This result is valid in the
framework of the gradient expansion and aims at compensating the lack of
non-renormalization theorems
Solutions of Quantum Gravity Coupled to the Scalar Field
We consider the Wheeler-De Witt equation for canonical quantum gravity
coupled to massless scalar field. After regularizing and renormalizing this
equation, we find a one-parameter class of its solutions.Comment: 8 pages, LaTe
Torsion Phenomenology at the LHC
We explore the potential of the CERN Large Hadron Collider (LHC) to test the
dynamical torsion parameters. The form of the torsion action can be established
from the requirements of consistency of effective quantum field theory. The
most phenomenologically relevant part of the torsion tensor is dual to a
massive axial vector field. This axial vector has geometric nature, that means
it does not belong to any representation of the gauge group of the SM extension
or GUT theory. At the same time, torsion should interact with all fermions,
that opens the way for the phenomenological applications.
We demonstrate that LHC collider can establish unique constraints on the
interactions between fermions and torsion field considerably exceeding present
experimental lower bounds on the torsion couplings and its mass. It is also
shown how possible non-universal nature of torsion couplings due to the
renormalization group running between the Planck and TeV energy scales can be
tested via the combined analysis of Drell-Yan and production
processes
On the Semi-Relative Condition for Closed (TOPOLOGICAL) Strings
We provide a simple lagrangian interpretation of the meaning of the
semi-relative condition in closed string theory. Namely, we show how the
semi-relative condition is equivalent to the requirement that physical
operators be cohomology classes of the BRS operators acting on the space of
local fields {\it covariant} under world-sheet reparametrizations. States
trivial in the absolute BRS cohomology but not in the semi-relative one are
explicitly seen to correspond to BRS variations of operators which are not
globally defined world-sheet tensors. We derive the covariant expressions for
the observables of topological gravity. We use them to prove a formula that
equates the expectation value of the gravitational descendant of ghost number 4
to the integral over the moduli space of the Weil-Peterson K\"ahler form.Comment: 10 pages, harvmac, CERN-TH-7084/93, GEF-TH-21/199
Charged Black Holes in Two-Dimensional String Theory
We discuss two dimensional string theories containing gauge fields introduced
either via coupling to open strings, in which case we get a Born-Infeld type
action, or via heterotic compactification. The solutions to the modified
background field equations are charged black holes which exhibit interesting
space-time geometries. We also compute their masses and charges.Comment: 39 page
Bound States of Type I D-Strings
We study the infra-red limit of the O(N) gauge theory that describes the low
energy modes of a system of type I D-strings and provide some support to
the conjecture that, in this limit, the theory flows to an orbifold conformal
theory. We compute the elliptic genus of the orbifold theory and argue that its
longest string sector describes the bound states of D-strings. We show that, as
a result, the masses and multiplicities of the bound states are in agreement
with the predictions of heterotic-type I duality in 9 dimensions, for all the
BPS charges in the lattice .Comment: 14 pages, (AMS-)LaTex file using amstex.st
Modified Black Holes in Two Dimensional Gravity
The gauged WZWN model is modified by a topological term and
the accompanying change in the geometry of the two dimensional target space is
determined. The possibility of this additional term arises from a symmetry in
the general formalism of gauging an isometry subgroup of a non-linear sigma
model with an antisymmetric tensor. It is shown, in particular, that the
space-time exhibits some general singularities for which the recently found
black hole is just a special case. From a conformal field theory point of view
and for special values of the unitary representations of , this
topological term can be interpreted as a small perturbation by a (1,1)
conformal operator of the gauged WZWN action.Comment: 12 page
Conformal invariance and QCD Pomeron vertices in the limit
Using the dipole framework for QCD at small x in the 1/N_c limit, we derive
the expression of the 1 -> p dipole multiplicity density in momentum space.
This gives an analytical expression for the 1 -> p QCD Pomeron amplitudes in
terms of one-loop integration of effective vertices in transverse momentum.
Conformal invariance and a Hilbert space construction for dipole correlation
functions are the main tools of the derivation. Relations with conformal field
theories in the classical limit are discussed.Comment: 16 pages, LATEX file, 1 .eps figur