807 research outputs found
Finite temperature holographic duals of 2-dimensional BCFTs
We consider holographic duals of -dimensional conformal field theories in
the presence of a boundary, interface, defect and/or junction, referred to
collectively as BCFTs. In general, the presence of a boundary reduces the
conformal symmetry to and the dual geometry is realized as
a warped product of the form , where is not
compact. In particular, it will contain points where the warp factor of the
space diverges, leading to asymptotically regions. We show that
the space-time may always be replaced with an -"black-hole"
space-time. We argue the resulting geometry describes the BCFT at finite
temperature. To motivate this claim, we compute the entanglement entropy
holographically for a segment centered around the defect or ending on the
boundary and find agreement with a known universal formula.Comment: 16 pages, 2 figures; minor corrections and references adde
Integrable systems from supergravity BPS equations
Integrable systems of the sine-Gordon/Liouville type, which arise from
reducing the BPS equations for solutions invariant under 16 supersymmetries in
Type IIB supergravity and M-theory, are shown to be special cases of an
infinite family of integrable systems, parametrized by an arbitrary real
function of a real variable. It is shown that, for each function , this
generalized integrable system may be mapped onto a system of linear equations,
which in turn may be integrated in terms of the two linearly independent
solutions of an ordinary linear second order differential equation which
depends only on the function .Comment: 7 page
Holographic two-point functions for Janus interfaces in the CFT
This paper investigates scalar perturbations in the top-down supersymmetric
Janus solutions dual to conformal interfaces in the CFT, finding
analytic closed-form solutions. We obtain an explicit representation of the
bulk-to-bulk propagator and extract the two-point correlation function of the
dual operator with itself, whose form is not fixed by symmetry alone. We give
an expression involving the sum of conformal blocks associated with the
bulk-defect operator product expansion and briefly discuss finite-temperature
extensions. To our knowledge, this is the first two-point function computation
for a fully-backreacted, top-down holographic defect.Comment: 30 pages, PDFLaTe
Near Horizon Geometry of Strings Ending on Intersecting D8/D4-branes
We consider solutions of massive IIA supergravity corresponding to the
half-BPS intersection of D8/D4-branes with fundamental strings. The
-dimensional intersection preserves the symmetry . We give a reduction and partial integration of the BPS equations for
this symmetry group. We then specialize to the cases of enhanced supersymmetry
corresponding to or . In the first case, we show
that the only solution with enhanced symmetry is given by the geometry
describing the near horizon geometry of D8/D4-branes in the presence of an
O8-plane. In the second case, we identify novel solutions corresponding to
fundamental strings ending on D8-branes and a second set of novel solutions
corresponding to fundamental strings ending on an O8-plane. In both cases, the
fundamental string geometry contains an asymptotically flat region where the
string coupling goes to zero. We also show that there are no solutions
corresponding to -dimensional CFTs, which one may have hoped to construct
by suspending fundamental strings between D8-branes.Comment: 36 pages, 6 figures (12 pdf figure files
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