17 research outputs found
On the Uniqueness of Supersymmetric Attractors
In this paper we discuss the uniqueness of supersymmetric attractors in four
dimensional N=2 supergravity theories coupled to n vector multiplets. We prove
that for a given charge configuration the supersymmetry preserving axion free
attractors are unique. We generalise the analysis to axionic attractors and
state the conditions for uniqueness explicitly. We consider the example of a
two-parameter model and find all solutions to the supersymmetric attractor
equations and discuss their uniqueness.Comment: 12 pages, Late
Multiple Single-Centered Attractors
In this paper we study spherically symmetric single-centered attractors in
N=2 supergravity in four dimensions. The attractor points are obtained by
extremising the effective black hole potential in the moduli space. Using the
4D-5D correspondence of critical points of the effective black hole potential
we argue the existence of multiple attractors in four dimensions and explicitly
construct a pair of multiple solutions in a simple two parameter model. We
further obtain explicit examples of two distinct non-supersymmetric attractors
in type IIA string theory compactified on K3 X T2 carrying D0-D4-D6 charges. We
compute the entropy of these attractors and analyse their stability in detail.Comment: Modifications in Section 3. Some incorrect results are removed and
the section is rewritte
Exact thermal correlators of holographic s
We compute the exact retarded Green's functions in thermal s with
chemical potential and angular momenta using holography respectively. We
consider the field equations satisfied by the quasi-normal modes in both
charged and rotating black holes in spacetime and mapped them to the Heun
equations by appropriate changes of variables. The AGT correspondence allows us
to find the connection formulae among the solutions of the Heun equations near
different singularities by using the crossing relations of the five-point
correlators in the Liouville . The connection formulae associated with the
boundary conditions imposed on the bulk field equations yield the exact thermal
correlators in the boundary .Comment: 15 page
Near-Extremal Freudenthal Duality
Freudenthal duality is, as of now, the unique non-linear map on
electric-magnetic (e.m.) charges which is a symmetry of the Bekenstein-Hawking
entropy of extremal black holes in Maxwell-Einstein-scalar theories in four
space-time dimensions. In this paper, we present a consistent generalization of
Freudenthal duality to near-extremal black holes, whose entropy is obtained
within a Jackiw-Teitelboim gravity upon dimensional reduction. We name such a
generalization near-extremal Freudenthal duality. Upon such a duality, two
near-extremal black holes with two different (and both small) temperatures have
the same entropy when their e.m. charges are related by a Freudenthal
transformation. By exploiting Descartes' rule of signs as well as Sturm's
Theorem, we show that our formulation of the near-extremal Freudenthal duality
is analytical and unique.Comment: 29 pages, 2 figure
Holographic Thermal Correlators for Hyperbolic s
We use holography to compute the exact form of retarded Green's functions for
a scalar operator with conformal dimension in a thermal CFT and in its
related counterpart with chemical potential in . In our
analysis, we recast the wave equation of a scalar field in the normal form of
Heun's equation in the dual gravity theories described by the AdS hyperbolic
blackhole and its charged version. Heun's equation is identified to the
semiclassical limit of the BPZ equation for a five-point correlator with one
degenerate field insertion in the Liouville theory on the Riemann sphere. The
crossing symmetry of conformal block in the Liouville theory eventually gives
rise to a set of connection formulas among the solutions of Heun's equation
evaluated at different regular singularities. We use the connection formula to
reproduce the leading order behaviors of the scalar field near the horizon as
well as near the boundary and achieve the exact form of the retarded thermal
Green's function. We show a recipe to obtain the exact retarded Green's
function for a thermal CFT dual to AdS blackbrane from a high-temperature limit
accompanied by a complex mapping on AdS hyperbolic blackhole. Moreover, we show
the retarded Green's function for the boundary CFT of Rindler AdS spacetime
admits a free integer parameter.Comment: 17 pages, 7 tables, references added, matches the version published
in JHE