Javier Tarrio

Holographic operator mixing and quasinormal modes on the brane

We provide a framework for calculating holographic Green’s functions from general bilinear actions and fields obeying coupled differential equations in the bulk. The matrix-valued spectral function is shown to be independent of the radial bulk coordinate, and hence, free from renormalization ambiguities. Applying this framework we improve the analysis of fluctuations in the D3/D7 system at finite baryon density, where the longitudinal perturbations of the world-volume gauge field couple to the scalar fluctuations of the brane embedding. We compute the spectral function and show how its properties are related to those of the quasinormal mode spectrum. We study the crossover from the hydrodynamic diffusive to the reactive regime and the movement of quasinormal modes as functions of temperature and density. We also compute their dispersion relations and find that they asymptote to the lightcone for large momenta.

A note on conductivity and charge diffusion in holographic flavor systems

We analyze the charge diffusion and conductivity in a Dp/Dq holographic setup that is dual to a supersymmetric Yang-Mills theory in p+1 dimensions with Nf << Nc flavor degrees of freedom at finite temperature and nonvanishing U(1) baryon number chemical potential. We provide a new derivation of the results that generalize the membrane paradigm to the present context. We perform a numerical analysis in the particular case of the D3/D7 flavor system. The results obtained support the validity of the Einstein relation at finite chemical potential.

Hydrodynamics of fundamental matter

First and second order transport coefficients are calculated for the strongly coupled

Electric/magnetic duality and RG flows in AdS4/CFT3

{\mathcal{N} = 4}

Charged D3-D7 plasmas: novel solutions, extremality and stability issues

SYM plasma coupled to massless fundamental matter in the Veneziano limit. The results, including among others the value of the bulk viscosity and some relaxation times, are presented at next-to-leading order in the flavor contribution. The bulk viscosity is found to saturate Buchel’s bound. This result is also captured by an effective single-scalar five-dimensional holographic dual in the Chamblin-Reall class and it is suggested to hold, in the limit of small deformations, for generic plasmas with gravity duals, whenever the leading conformality breaking effects are driven by marginally (ir)relevant operators. This proposal is then extended to other relations for hydrodynamic coefficients, which are conjectured to be universal for every non-conformal plasma with a dual Chamblin-Reall-like description. Our analysis extends to any strongly coupled gauge theory describing the low energy dynamics of Nc ≫ 1 D3-branes at the tip of a generic Calabi-Yau cone. The fundamental fields are added by means of 1 ≪ Nf ≪ Nc homogeneously smeared D7-branes.

BPS black holes from massive IIA on S 6

A bstractA large set of relevant deformations of the ABJM field theory defined on a stack of M2 branes is captured holographically by D = 4

Three-dimensional super Yang-Mills with compressible quark matter

\mathcal{N}

(Super)Yang-Mills at Finite Heavy-Quark Density

= 8 SO(8)-gauged supergravity, which has accordingly been applied to study renormalisation group (RG) flows of the field theory between distinct superconformal phases. Recently, it has been discovered that this supergravity is not unique, and that a one-parameter family of gaugings of maximal supergravity exists. The parameter is an angle that measures the mixture of electric and magnetic vectors that gauge SO(8) dyonically. We construct and comprehensively characterise all domain walls between the critical points of the new supergravities with at least SU(3) invariance, which are expected to be dual to RG flows of new field theories defined at least at large N. We also construct some walls running off to infinity in scalar space, which we expect to be dual to Coulomb branch flows of these field theories.

Transport properties of spacetime-filling branes

A bstractWe study finite temperature

Towards a Holographic Quark Matter Crystal

\mathcal{N}=4