27 research outputs found
Chern-Simons Gravity and Holographic Anomalies
We present a holographic treatment of Chern-Simons (CS) gravity theories in
odd dimensions. We construct the associated holographic stress tensor and
calculate the Weyl anomalies of the dual CFT.Comment: Added references, and minor corrections. 21 pages, havmac, no figure
Numerical determination of entanglement entropy for a sphere
We apply Srednicki's regularization to extract the logarithmic term in the
entanglement entropy produced by tracing out a real, massless, scalar field
inside a three dimensional sphere in 3+1 flat spacetime. We find numerically
that the coefficient of the logarithm is -1/90 to 0.2 percent accuracy, in
agreement with an existing analytical result
Comments on Anomalies in Supersymmetric Theories
We analyse the relation between anomalies in their manifestly supersymmetric formulation in superspace and their formulation in Wess-Zumino (WZ) gauges. We show that there is a one-to-one correspondence between the solutions of the cohomology problem in the two formulations and that they are related by a particular choice of a superspace counterterm ("scheme"). Any apparent violation of -supersymmetry is due to an explicit violation by the counterterm which defines the scheme equivalent to the WZ gauge. It is therefore removable
Analyticity Properties of Graham-Witten Anomalies
Analytic properties of Graham-Witten anomalies are considered. Weyl anomalies
according to their analytic properties are of type A (coming from
-singularities in correlators of several energy-momentum tensors) or of
type B (originating in counterterms which depend logarithmically on a mass
scale). It is argued that all Graham-Witten anomalies can be divided into 2
groups: internal and external, and that all external anomalies are of type B,
whereas among internal anomalies there is one term of type A and all the rest
are of type B. This argument is checked explicitly for the case of a free
scalar field in a 6-dimensional space with a 2-dimensional submanifold.Comment: 2 typos correcte
Spontaneous Breaking of Conformal Invariance and Trace Anomaly Matching
We argue that when conformal symmetry is spontaneously broken the trace
anomalies in the broken and unbroken phases are matched. This puts strong
constraints on the various couplings of the dilaton. Using the uniqueness of
the effective action for the Goldstone supermultiplet for broken
superconformal symmetry the dilaton effective action is calculated.Comment: 29 pages, 2 figure
Universal Features of Holographic Anomalies
We study the mechanism by which gravitational actions reproduce the trace
anomalies of the holographically related conformal field theories. Two
universal features emerge: a) the ratios of type B trace anomalies in any even
dimension are independent of the gravitational action, being uniquely
determined by the underlying algebraic structure b) the normalization of the
type A and the overall normalization of the type B anomalies are given by
action dependent expressions with the dimension dependence completely fixed.Comment: 17 pages, harvma
Remarks on Resonant Scalars in the AdS/CFT Correspondence
The special properties of scalars having a mass such that the two possible
dimensions of the dual scalar respect the unitarity and the
Breitenlohner-Freedman bounds and their ratio is integral (``resonant
scalars'') are studied in the AdS/CFT correspondence. The role of logarithmic
branches in the gravity theory is related to the existence of a trace anomaly
and to a marginal deformation in the Conformal Field Theory. The existence of
asymptotic charges for the conformal group in the gravity theory is interpreted
in terms of the properties of the corresponding CFT.Comment: 16 pages, 1 figur
Violation of Energy Bounds in Designer Gravity
We continue our study of the stability of designer gravity theories, where
one considers anti-de Sitter gravity coupled to certain tachyonic scalars with
boundary conditions defined by a smooth function W. It has recently been argued
there is a lower bound on the conserved energy in terms of the global minimum
of W, if the scalar potential arises from a superpotential P and the scalar
reaches an extremum of P at infinity. We show, however, there are
superpotentials for which these bounds do not hold.Comment: 16 pages, 4 figures, v2: discussion of vacuum decay included, typos
corrected, reference adde
Entanglement Entropy, Trace Anomalies and Holography
The holographic representation of the entanglement entropy of four
dimensional conformal field theories is studied. By generalizing the replica
trick the anomalous terms in the entanglement entropy are evaluated. The same
terms in the holographic representation are calculated by a method which does
not require the solution of the equations of motion or a cut off. The two
calculations disagree for rather generic geometries. The reasons for the
disagreement are analyzed.Comment: 33 pages, 1 figure; v2: references and two footnotes added, typos
correcte
Diffeomorphisms and Holographic Anomalies
Using the relation between diffeomorphisms in the bulk and Weyl
transformations on the boundary we study the Weyl transformation properties of
the bulk metric on shell and of the boundary action. We obtain a universal
formula for one of the classes of trace anomalies in any even dimension in
terms of the parameters of the gravity action.Comment: 12 pages, harvma