arXiv subjects
Publications and source records attributed to Justin F. Vazquez-Poritz.
We find that the drag force for a heavy quark moving through N=4 SU(N_c) supersymmetric Yang-Mills plasma is generally enhanced by the leading correction due to finite 't Hooft coupling. For a bottom quark, the drag force increases by about 50%, whereas for a charm quark it increases by about 5%. We also discuss the drag force for the case of Gauss-Bonnet gravity.
We construct supergravity solutions describing a stack of D3-branes localized at a point on a blown-up cycle of a resolved L^{a,b,c} cone. The geometry flows from AdS_5 x L^{a,b,c} to AdS_5 x S^5/Z_k. The corresponding quiver gauge theory undergoes an RG flow between two superconformal fixed points, which leads to semi-infinite chains of flows between the various L^{a,b,c} fixed points. The general system is described by a triplet of Heun equations which can each be solved by an expansion with a three-term recursion relation, though there are closed-form solutions for certain cases. This enables us to read off the operators which acquire non-zero vacuum expectation values as the quiver gauge theory flows away from a fixed point.
We investigate the lightlike limit of stationary spacelike string configurations on a large class of five-dimensional asymptotically AdS backgrounds. Specific examples include gravity duals which incorporate finite 't Hooft coupling, curvature-squared corrections, and chemical potentials. A universal feature of these AdS/CFT models is that the string solution with minimum action yields a lightlike Wilson loop whose leading behavior is exponentially linear, rather than quadratic, in the width of the loop. Unless there is a compelling reason for discarding the leading saddlepoint contribution to the Wilson loop, following the proposal of Liu et. al. [2] leads to zero jet-quenching parameter for all of these models.
We construct new supersymmetric solutions, including AdS bubbles, in an N=2 truncation of five-dimensional N=8 gauged supergravity. This particular truncation is given by N=2 gauged supergravity coupled to two vector multiples and three incomplete hypermultiplets, and was originally investigated in the context of obtaining regular AdS bubble geometries with multiple active R-charges. We focus on cohomogeneity-one solutions corresponding to objects with two equal angular momenta and up to three independent R-charges. Curiously, we find a new set of zero and negative mass solitons asymptotic to AdS_5/Z_k, for k \ge 3, which are everywhere regular without closed timelike curves.
We explore the non-BPS analog of `AdS bubbles', which are regular spherically symmetric 1/2 BPS geometries in type IIB supergravity. They have regular horizons and can be thought of as bubbling generalizations of non-extremal AdS black hole solutions in five-dimensional gauged supergravity. Due to the appearance of the Heun equation even at the linearized level, various approximation and numerical methods are needed in order to extract information about this system. We study how the vacuum expectation value and mass of a particular dimension two chiral primary operator depend on the temperature and chemical potential of the thermal Yang-Mills theory. In addition, the mass of the bubbling AdS black holes is computed. As is shown numerically, there are also non-BPS solitonic bubbles which are completely regular and arise from continuous deformations of BPS AdS bubbles.
We investigate the behavior of stationary string configurations on a five-dimensional AdS black hole background which correspond to quark-antiquark pairs steadily moving in an N=4 super Yang-Mills thermal bath. There are many branches of solutions, depending on the quark velocity and separation as well as on whether Euclidean or Lorentzian configurations are examined.
We investigate stationary string solutions with spacelike worldsheet in a five-dimensional AdS black hole background, and find that there are many branches of such solutions. Using a non-perturbative definition of the jet quenching parameter proposed by Liu et. al., hep-ph/0605178, we take the lightlike limit of these solutions to evaluate the jet quenching parameter in an N=4 super Yang-Mills thermal bath. We show that this proposed definition gives zero jet quenching parameter, independent of how the lightlike limit is taken. In particular, the minimum-action solution giving the dominant contribution to the Wilson loop has a leading behavior that is linear, rather than quadratic, in the quark separation.
We consider type IIB supergravity backgrounds which describe marginal deformations of the Coulomb branch of N=4 super Yang-Mills theory with SO(4) x SO(2) global symmetry. Wilson loop calculations indicate that certain deformations enhance the Coulombic attraction between quarks and anti-quarks at the UV conformal fixed-point. In the IR region, these deformations can induce a transition to linear confinement.
A number of recent papers have applied the AdS/CFT correspondence to a strong-coupling calculation of the medium-induced radiative parton energy loss in nucleus-nucleus collisions at RHIC. The predicted value of the "jet quenching parameter" q, however, is rather small compared to the experimental results. For hot N=4 supersymmetric Yang-Mills theory, certain marginal deformations can have the effect of enhancing q. This result is highly sensitive to the location of the fundamental string's endpoints in the internal space.
We consider supersymmetric SL(3,R) deformations of various type IIB supergravity backgrounds which exhibit flows away from an asymptotically locally AdS_5 x S^5 fixed point. This includes the gravity dual of the Coulomb branch of N=1 super Yang Mills theory, for which the deformed superpotential is known. We also consider the gravity duals of field theories which live on various curved backgrounds, such as Minkowski_2 x H^2, AdS_3 x S^1 and R x S^3. Some of the deformed theories flow from a four-dimensional N=1 superconformal UV fixed point to a two-dimensional (2,2) superconformal IR fixed point. We study nonsupersymmetric generalizations of the deformations of the above Coulomb branch flows.
We generate new 11-dimensional supergravity solutions from deformations based on U(1)^3 symmetries. The initial geometries are of the form AdS_4 x Y_7, where Y_7 is a 7-dimensional Sasaki-Einstein space. We consider a general family of cohomogeneity one Sasaki-Einstein spaces, as well as the recently-constructed cohomogeneity three L^{p,q,r,s} spaces. For certain cases, such as when the Sasaki-Einstein space is S^7, Q^{1,1,1} or M^{1,1,1}, the deformed gravity solutions correspond to a marginal deformation of a known dual gauge theory.
We construct various non-singular p-branes on higher-dimensional generalizations of Taub-NUT and Taub-BOLT instantons. Among other solutions, these include S^1-wrapped D3-branes and M5-branes, as well as deformed M2-branes. The resulting geometries smoothly interpolate between product spaces which include Minkowski elements of different dimensionality. The new solutions do not preserve any supersymmetry.