185 research outputs found
Real-time gauge/gravity duality and ingoing boundary conditions
In arXiv:0805.0150 [hep-th] and arXiv:0812.2909 [hep-th] a general
prescription was presented for the computation of real-time correlation
functions using the gauge/gravity duality. I apply this prescription to the
specific case of retarded thermal correlation functions and derive the usual
ingoing boundary conditions at the horizon for bulk fields. The derivation
allows me to clarify various issues, in particular the generalization to
higher-point functions and the relevance of including the regions beyond the
horizon.Comment: 5 pages, 2 figures; expanded version of contribution to the Cargese
2008 proceeding
Conformal Invariance in the Long-Range Ising Model
We consider the question of conformal invariance of the long-range Ising
model at the critical point. The continuum description is given in terms of a
nonlocal field theory, and the absence of a stress tensor invalidates all of
the standard arguments for the enhancement of scale invariance to conformal
invariance. We however show that several correlation functions, computed to
second order in the epsilon expansion, are nontrivially consistent with
conformal invariance. We proceed to give a proof of conformal invariance to all
orders in the epsilon expansion, based on the description of the long-range
Ising model as a defect theory in an auxiliary higher-dimensional space. A
detailed review of conformal invariance in the d-dimensional short-range Ising
model is also included and may be of independent interest.Comment: 52pp; V2: refs added; V3: ref added, published versio
QFT in AdS instead of LSZ
The boundary correlation functions for a QFT in a fixed AdS background should
reduce to S-matrix elements in the flat-space limit. We consider this procedure
in detail for four-point functions. With minimal assumptions we rigorously show
that the resulting S-matrix element obeys a dispersion relation, the non-linear
unitarity conditions, and the Froissart-Martin bound. QFT in AdS thus provides
an alternative route to fundamental QFT results that normally rely on the LSZ
axioms.Comment: 8 pages, 1 figur
AdS boundary conditions and the Topologically Massive Gravity/CFT correspondence
The AdS/CFT correspondence provides a new perspective on recurrent questions
in General Relativity such as the allowed boundary conditions at infinity and
the definition of gravitational conserved charges. Here we review the main
insights obtained in this direction over the last decade and apply the new
techniques to Topologically Massive Gravity. We show that this theory is dual
to a non-unitary CFT for any value of its parameter mu and becomes a
Logarithmic CFT at mu = 1.Comment: 10 pages, proceedings for XXV Max Born Symposium, talks given at
Johns Hopkins workshop and Holographic Cosmology workshop at Perimeter
Institute; v2: added reference
Applications of alpha space
We extend the definition of ‘alpha space’ as introduced in [1] to two spacetime dimensions. We discuss how this can be used to find conformal block decompositions of known functions and how to easily recover several lightcone bootstrap results. In the second part of the paper we establish a connection between alpha space and the Lorentzian inversion formula of [2]
Regge trajectories for the (2,0) theories
We investigate the structure of conformal Regge trajectories for the maximally supersymmetric (2, 0) theories in six dimensions. The different conformal multiplets in a single superconformal multiplet must all have similarly-shaped Regge trajectories. We show that these super-descendant trajectories interact in interesting ways, leading to new constraints on their shape. For the four-point function of the stress tensor multiplet supersymmetry also softens the Regge behavior in some channels, and consequently we observe that ‘analyticity in spin’ holds for all spins greater than −3. All the physical operators in this correlator therefore lie on Regge trajectories and we describe an iterative scheme where the Lorentzian inversion formula can be used to bootstrap the four-point function. Some numerical experiments yield promising results, with OPE data approaching the numerical bootstrap results for all theories with rank greater than one
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