33 research outputs found
Open String Creation by S-Branes
An sp-brane can be viewed as the creation and decay of an unstable
D(p+1)-brane. It is argued that the decaying half of an sp-brane can be
described by a variant of boundary Liouville theory. The pair creation of open
strings by a decaying s-brane is studied in the minisuperspace approximation to
the Liouville theory. In this approximation a Hagedorn-like divergence is found
in the pair creation rate, suggesting the s-brane energy is rapidly transferred
into closed string radiation.Comment: Talk presented at the Hangzhou String 2002 Conference, August 12-1
AdS vacua and RG flows in three dimensional gauged supergravities
We study supersymmetric vacua in N=4 and N=8, three dimensional
gauged supergravities, with scalar manifolds and , non-semisimple Chern-Simons
gaugings and ,
respectively. These are in turn equivalent to SO(4) and
Yang-Mills theories coupled to supergravity. For the N=4 case, we study
renormalization group flows between UV and IR vacua with the same
amount of supersymmetry: in one case, with (3,1) supersymmetry, we can find an
analytic solution whereas in another, with (2,0) supersymmetry, we give a
numerical solution. In both cases, the flows turn out to be v.e.v. flows, i.e.
they are driven by the expectation value of a relevant operator in the dual
. These provide examples of v.e.v. flows between two vacua
within a gauged supergravity framework.Comment: 35 pages in JHEP form, 3 figures, typos corrected, references adde
3D N=6 Gauged Supergravity: Admissible Gauge Groups, Vacua and RG Flows
We study N=6 gauged supergravity in three dimensions with scalar manifolds
for in great details. We
classify some admissible non-compact gauge groups which can be consistently
gauged and preserve all supersymmetries. We give the explicit form of the
embedding tensors for these gauge groups as well as study their scalar
potentials on the full scalar manifold for each value of along with
the corresponding vacua. Furthermore, the potentials for the compact gauge
groups, for ,
identified previously in the literature are partially studied on a submanifold
of the full scalar manifold. This submanifold is invariant under a certain
subgroup of the corresponding gauge group. We find a number of supersymmetric
AdS vacua in the case of compact gauge groups. We then consider holographic RG
flow solutions in the compact gauge groups and
for the k=4 case. The solutions
involving one active scalar can be found analytically and describe operator
flows driven by a relevant operator of dimension 3/2. For non-compact gauge
groups, we find all types of vacua namely AdS, Minkowski and dS, but there is
no possibility of RG flows in the AdS/CFT sense for all gauge groups considered
here.Comment: 43 pages, no figures references added, typoes corrected and more
information adde
All the timelike supersymmetric solutions of all ungauged d=4 supergravities
We determine the form of all timelike supersymmetric solutions of all N
greater or equal than 2, d=4 ungauged supergravities, for N less or equal than
4 coupled to vector supermultiplets, using the $Usp(n+1,n+1)-symmetric
formulation of Andrianopoli, D'Auria and Ferrara and the spinor-bilinears
method, while preserving the global symmetries of the theories all the way. As
previously conjectured in the literature, the supersymmetric solutions are
always associated to a truncation to an N=2 theory that may include
hypermultiplets, although fields which are eliminated in the truncations can
have non-trivial values, as is required by the preservation of the global
symmetry of the theories. The solutions are determined by a number of
independent functions, harmonic in transverse space, which is twice the number
of vector fields of the theory (n+1). The transverse space is flat if an only
if the would-be hyperscalars of the associated N=2 truncation are trivial.Comment: v3: Some changes in the introduction. Version to be published in JHE