181 research outputs found
The large D limit of dimensionally continued gravity
In a recent paper [arXiv:1302.6382] Emparan, Suzuki, and Tanabe studied
general relativity in the limit in which the number of spacetime dimensions D
tends to infinity. They showed that, in such limit, the theory simplifies
notably. It reduces to a theory whose fundamental objects, black holes and
black branes, behave as non-interacting particles. Here, we consider a
different way of extending gravity to D dimensions. We present a special limit
of dimensionally continued gravity in which black holes retain their
gravitational interaction at large D and still have entropy proportional to the
mass. The similarities and differences with the limit considered in
[arXiv:1302.6382] are discussed.Comment: 10 page
Scattering of low lying states in the black hole atmosphere
We investigate finite effects in string theory on a black hole
background. By explicitly computing tree level scattering amplitudes, we
confirm a duality between seemingly different states recently conjectured by
Giveon, Itzhaki, and Kutasov in [arXiv:1603.05822]. We verify that the relevant
3-point functions factorize in such a way that the duality between oscillator
and winding states becomes manifest. This leads to determine the precise
normalization of the dual vertex operators, and confirms at the level of the
interacting theory the identification of states suggested by the analysis of
the spectrum. This result implies a duality between two seemingly distinct
mechanisms driving the violation of the string winding number in the black hole
atmosphere.Comment: 12 pages, 1 figur
TT-deformations, AdS/CFT and correlation functions
A solvable irrelevant deformation of AdS3/CFT2 correspondence leading to a theory with Hagedorn spectrum at high energy has been recently proposed. It consists of a single trace deformation of the boundary theory, which is inspired by the recent work on solvable TT¯ deformations of two-dimensional CFTs. Thought of as a worldsheet σ-model, the interpretation of the deformed theory from the bulk viewpoint is that of string theory on a background that interpolates between AdS3 in the IR and a linear dilaton vacuum of little string theory in the UV. The insertion of the operator that realizes the deformation in the correlation functions produces a logarithmic divergence, leading to the renormalization of the primary operators, which thus acquire an anomalous dimension. We compute this anomalous dimension explicitly, and this provides us with a direct way of determining the spectrum of the theory. We discuss this and other features of the correlation functions in presence of the deformation.Fil: Giribet, Gaston Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Física; Argentin
Aspects of the free field description of string theory on AdS_3
The near boundary limit of string theory in AdS_3 is analysed using the
Wakimoto free field representation of SL(2,R). The theory is considered as a
direct product of the SL(2,R)/U(1) coset and a free boson. Correlation
functions are constructed generalizing to the non-compact case the integral
representation of conformal blocks introduced by Dotsenko in the compact SU(2)
CFT. Sectors of the theory obtained by spectral flow manifestly appear. The
formalism naturally leads to consider scattering processes violating winding
number conservation. The consistency of the procedure is verified in the
factorization limit.Comment: 25 pages, typos corrected, references added, to appear in JHE
Screening Stringy Horizons
It has been argued recently that string theory effects qualitatively modify
the effective black hole geometry experienced by modes with radial momentum of
order . At tree level, these -effects can be
explicitly worked out in two-dimensional string theory, and have a natural
explanation in the T-dual description as coming from the integration of the
zero-mode of the linear dilaton, what yields a contribution that affects the
scattering phase-shift in a peculiar manner. It has also been argued that the
phase-shift modification has its origin in a region of the moduli space that
does not belong to the exterior black hole geometry, leading to the conclusion
that at high energy the physics of the problem is better described by the dual
model. Here, we elaborate on this argument. We consider the contribution of
worldsheet instantons in the 2D Euclidean black hole sigma-model and study its
influence on the phase-shift at high energy.Comment: 14 page
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