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.
118385203
Towards multi-scale dynamics on the baryonic branch of Klebanov-Strassler
We construct explicitly a new class of backgrounds in type-IIB supergravity which generalize the baryonic branch of Klebanov-Strassler. We apply a solution-generating technique that, starting from a large class of solutions of the wrapped-D5system, yields the new solutions, and then proceed to study in detail their properties, both in the IR and in the UV. We propose a simple intuitive field theory interpretation of the rotation procedure and of the meaning of our new solutions within the Papadopoulos-Tseytlin ansatz, in particular in relation to the duality cascade in the Klebanov-Strassler solution. The presence in the field theory of different VEVs for operators of dimensions 2, 3 and 6 suggests that this is an important step towards the construction of the string dual of a genuinely multi-scale (strongly coupled) dynamical model.
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.
119640171
Cosmology from String Theory
We explore the cosmological content of Salam-Sezgin six dimensional supergravity, and find a solution to the field equations in qualitative agreement with observation of distant supernovae, primordial nucleosynthesis abundances, and recent measurements of the cosmic microwave background. The carrier of the acceleration in the present de Sitter epoch is a quintessence field slowly rolling down its exponential potential. Intrinsic to this model is a second modulus which is automatically stabilized and acts as a source of cold dark matter, with a mass proportional to an exponential function of the quintessence field (hence realizing VAMP models within a String context). However, any attempt to saturate the present cold dark matter component in this manner leads to unacceptable deviations from cosmological data – a numerical study reveals that this source can account for up to about 7% of the total cold dark matter budget. We also show that (1) the model will support a de Sitter energy in agreement with observation at the expense of a miniscule breaking of supersymmetry in the compact space; (2) variations in the fine structure constant are controlled by the stabilized modulus and are negligible; (3) “fifth” forces are carried by the stabilized modulus and are short range; (4) the long time behavior of the model in four dimensions is that of a Robertson-Walker universe with a constant expansion rate (w = −1/3). Finally, we present a String theory background by lifting our six dimensional cosmological solution to ten dimensions.
119516505
Supersymmetry and Bogomol'nyi equations in the Abelian Higgs model
Abstract The N = 2 supersymmetric extension of the 2+1 dimensional Abelian Higgs model is discussed. By analysing the resulting supercharge algebra, the connection between supersymmetry and Bogomol'nyi equations is clarified. Analogous results are presented when the model is considered in 2 dimensional (Euclidean) space.
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.
121030693
Vacuum polarization in curved backgrounds deduced from Hadamard kernels
The point‐splitting method of regularization is applied to alternative Hadamard kernels, for scalar fields in curved backgrounds, in order to study the polarization term in the vacuum expectation value (VEV) of the energy‐momentum tensor. An ansatz to define this term is introduced and verified in several cases. The renormalized VEV of the energy‐momentum tensor of a scalar massive conformally coupled field in a Robertson–Walker universe is explicitly computed. Two terms appear, the polarization term, which coincides with the one computed using the above‐mentioned ansatz, and a creation of particle term.
118238008
THE LOCAL TERM OF THE ENERGY MOMENTUM TENSOR FOR A QUANTUM SCALAR FIELD IN A CURVED BACKGROUND
14227643
Aspects of the free field description of string theory on AdS3
The near boundary limit of string theory in AdS3 is analysed using the Wakimoto free field representation of SL(2,). The theory is considered as a direct product of the SL(2,)/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.
8091709
Winding strings in AdS3
Correlation functions of one-unit spectral flowed states in string theory on AdS3 are considered. We present the modified Knizhnik-Zamolodchikov and null vector equations to be satisfied by amplitudes containing states in winding sector one and study their solution corresponding to the four point function including one w = 1 field. We compute the three point function involving two one-unit spectral flowed operators and find expressions for amplitudes of three w = 1 states satisfying certain particular relations among the spins of the fields. Several consistency checks are performed.
118790133
On Type IIB moduli stabilization and N=4,8 supergravities
Abstract We analyze D = 4 compactifications of Type IIB theory with generic, geometric and non-geometric, dual fluxes turned on. In particular, we study N = 1 toroidal orbifold compactifications that admit an embedding of the untwisted sector into gauged N = 4 , 8 supergravities. Truncations, spontaneous breaking of supersymmetry and the inclusion of sources are discussed. The algebraic identities satisfied by the supergravity gaugings are used to implement the full set of consistency constraints on the background fluxes. This allows to perform a generic study of N = 1 vacua and identify large regions of the parameter space that do not admit complete moduli stabilization. Illustrative examples of AdS and Minkowski vacua are presented.