119284427
A Light scalar from walking solutions in gauge-string duality
Abstract We consider the type-IIB background generated by the strong-coupling limit of N c D5 branes wrapped on S 2 , and focus our attention on a special class of solutions that exhibit walking behavior. We compute numerically the spectrum of scalar fluctuations around vacua of this class. Besides two cuts, and sequences of single poles converging on one of the branch points, the spectrum contains one isolated scalar, the mass of which is suppressed by the length of the walking region. Approximate scale-invariance symmetry in the walking region suggests that this might be interpreted as a light dilaton, the pseudo-Goldstone boson of dilatations.
15805106
String duals of two-dimensional (4,4) supersymmetric gauge theories
We study duals to field theories in two dimensions with = (4, 4) SUSY. The string backgrounds reproduce certain non-perturbative aspects of the dual field theory with a large number of colors Nc and a tunable number of flavors Nf. Different aspects of the two-dimensional field theory are discussed, among them the running of gauge couplings, the spectrum of mesons in Higgs and Coulomb branches, entanglement entropy and the non-relativistic version of our string backgrounds.
17311968
Backreacting flavors in the Klebanov-Strassler background
In this paper we present new analytic solutions of pure Type IIB supergravity plus D7-branes describing the addition of an arbitrary number of flavors to the Klebanov-Tseytlin and Klebanov-Strassler backgrounds. We provide a precise field theory dual and a detailed analysis of the duality cascade which describes its RG flow. Matchings of beta functions and anomalies between the field theory and the string setup are presented. We give an understanding of Seiberg duality as a large gauge transformation on the RR and NSNS potentials. We also analyze the UV behavior of the field theory that, as suggested by the string background, can be associated with a duality wall.
121982373
Fermionic current algebra in three dimensions
We consider the fermion-boson mapping in three dimensional space-time, in the Abelian case, from the current algebra point of view. It is shown that in a path-integral framework one can derive a general bosonization recipe leading, in the bosonic language, to the correct equal-time current commutators of the original free fermionic theory.
12143928
Unquenched flavors in the Klebanov-Witten model
Using AdS/CFT, we study the addition of an arbitrary number of backreacting flavors to the Klebanov-Witten theory, making many checks of consistency between our new Type IIB plus branes solution and expectations from field theory. We study generalizations of our method for adding flavors to all = 1 SCFTs that can be realized on D3-branes at the tip of a Calabi-Yau cone. Also, general guidelines suitable for the addition of massive flavor branes are developed.
8824397
Fake supergravity and domain wall stability
We review the generalized Witten-Nester spinor stability argument for flat domain wall solutions of gravitational theories. Neither the field theory nor the solution need be supersymmetric. Nor is the space-time dimension restricted. We develop the non-trivial extension required for AdS-sliced domain walls and apply this to show that the recently proposed "Janus" solution of Type IIB supergravity is stable non-perturbatively for a broad class of deformations. Generalizations of this solution to arbitrary dimension and a simple curious linear dilaton solution of Type IIB supergravity are byproducts of this work.
95905439
Aspects of D-brane dynamics on orbifolds
We discuss D-brane dynamics in orbifold compactifications of type II superstring theory. We compute the interaction potential between two D-branes moving with constant velocities and give a field theory interpretation of it in the large distance limit.
5975372
Quantum corrections and extremal black holes
Abstract We consider static solutions of two dimensional dilaton gravity models as toy laboratories to address the question of the final fate of black holes. A nonperturbative correction to the CGHS potential tern is shown to lead classically to an extremal black hole geometry, thus providing a plausible solution to the Hawking evaporation paradox. However, the full quantum theory does not admit an extremal solution.
118270106
Minimal Hypotheses for Particle Definition in Curved Space-Time
The interaction between a quantum field and an unquantized gravitational field can be studied in the frame of a semiclassical theory in which the gravitational field enters, according to the theory of general relativity, as the background geometry, where the covariant generalizations of Klein-Gordon, Dirac, Maxwell, etc. equations are considered1. Such a theory is supposed to be a good approximation to a more general, as yet unknown, full quantum theory, when the components of the Riemann curvature tensor are small (in atomic units, h = c = 1) as compared to the Planck energy (1019 GeV) squared. One of the most striking results of this formulation is the possibility of particle- antiparticle-pairs creation by a dynamical gravitational field, the thermal radiation of black holes predicted by Hawking2 being its most popular version. Particle creation in asymptotically static universes, where the particle model (the plane waves) is perfectly defined in the far future and past, has also been studied3. But the universe has undoubtly not been static in the past; then an “in-out” theory is unrealistic.
14232422
Four point functions in the SL(2,R) WZW model
Abstract We consider winding conserving four point functions in the SL ( 2 , R ) WZW model for states in arbitrary spectral flow sectors. We compute the leading order contribution to the expansion of the amplitudes in powers of the cross ratio of the four points on the worldsheet, both in the m - and x -basis, with at least one state in the spectral flow image of the highest weight discrete representation. We also perform certain consistency check on the winding conserving three point functions.
124520602
Nondiagonal CP(m) cosets in string compactifications