This thesis is dedicated to the holographic study of flavor dynamics. The technique employed is a D7-brane probing of various D3-brane backgrounds. The first topic covered studies the influence of an external magnetic field on a flavored large N Yang-Mills theory. The theory exhibits spontaneous chiral symmetry breaking. The meson spectrum exhibits Zeeman splitting and characteristic GMOR relation. The second topic examines thermal properties of the dual gauge theory. The third topic studies the phase structure of the finite temperature dual gauge theory in the presence of magnetic field. A phase diagram of the theory is obtained and the meson spectrum is explored. The fourth topic studies the addition of an external electric field. The observed effect is dissociation of the bound quarks, favoring the meson melting, the dissociation of mesons corresponds to an insulator/conductor phase transition. The fifth topic studies the addition of an R-charge chemical potential via brane probing of the spinning D3-brane geometry. The corresponding phase diagram is obtained. The chemical potential favors the dissociation of mesons. The last topic explores universal properties of gauge theories dual to the Dp/Dq system. A universal discrete self-similar behavior associated to the insulator/conductor phase transition is observed and the corresponding scaling exponents are computed.
Quantum complexity of a thermofield double state in a strongly coupled quantum field theory has been argued to be holographically related to the action evaluated on the Wheeler-DeWitt patch. The growth rate of quantum complexity in systems dual to Einstein-Hilbert gravity saturates a bound which follows from the Heisenberg uncertainty principle. We consider corrections to the growth rate in models with flavor degrees of freedom. They are realized by adding a small number of flavor branes to the system. Holographically, such corrections come from the DBI action of the flavor branes evaluated on…
We derive a new class of supersymmetric D3/D7 brane configurations, which allow to holographically describe N=4 SYM coupled to massive N=2 flavor degrees of freedom on spaces of constant curvature. We systematically solve the $κ$-symmetry condition for D7-brane embeddings into AdS$_4$-sliced AdS$_5\times$S$^5$, and find supersymmetric embeddings in a simple closed form. Up to a critical mass, these embeddings come in surprisingly diverse families, and we present a first study of their (holographic) phenomenology. We carry out the holographic renormalization, compute the one-point functions and…
In this paper we study the holographic dual, in several spacetime dimensions, of the Higgs branch of gauge theories with fundamental matter. These theories contain defects of various codimensionalities, where the matter fields are located. In the holographic description the matter is added by considering flavor brane probes in the supergravity backgrounds generated by color branes, while the Higgs branch is obtained when the color and flavor branes recombine with each other. We show that, generically, the holographic dual of the Higgs phase is realized by means of the addition of extra flux on…
We construct holographic duals to N=1 SQCD with a quartic superpotential and unquenched massive flavors. Our backgrounds are generated by D5-branes wrapping two-dimensional submanifolds of an internal space. The flavor degrees of freedom are introduced by means of D5-branes extended along two-dimensional calibrated surfaces, and act as sources of the different supergravity fields. The backgrounds we get include the backreaction of the flavor branes and generalize the geometries obtained so far to the case in which the fundamental matter is massive. The supergravity solutions we find are regula…
In this paper we review some results on the generalization of the gauge/gravity duality to include fundamental matter by means of probe branes. We compute the meson spectrum of maximally supersymmetric gauge theories in several dimensions, both in the Coulomb and Higgs branch. We also study the addition of flavor and compute the meson spectrum for non-commutative theories. Additionally, we present a thorough search of supersymmetric embeddings of probe branes in the Klebanov-Witten model.
The notion of generalized gravitational entropy introduced by Lewkowycz and Maldacena allows, via the AdS/CFT correspondence, to calculate CFT entanglement entropies. We adapt the method to the case where flavor branes are present and treated in the probe approximation. This allows to calculate the leading flavor correction to the CFT entanglement entropy from the on-shell action of the probe, while dealing with the backreaction is avoided entirely and from the outset. As an application we give concise derivations for the contribution of massless and massive flavor degrees of freedom to the en…
We use gauge-gravity duality to study a strongly-coupled non-Abelian gauge theory with flavor fields, i.e. fields transforming in the fundamental representation of the gauge group. We first study the thermodynamics of the flavor fields. In the grand canonical ensemble at zero temperature, we find a second-order transition when the mass of the flavor fields equals the chemical potential. We then study the transport properties of the flavor fields at finite temperature and density. We introduce external electric and magnetic fields and compute the resulting current of flavor charge. From this cu…
Gauge theory with light flavor quark is studied by embedding a D7 brane in a deconfinement phase background newly constructed. We find a phase transition by observing a jump of the vacuum expectation value of quark bilinear and also of the derivative of D7 energy at a critical temperature. For the model considered here, we also study quark-antiquark potential to see some possible quark-bound states and other physical quantities in the deconfinement phase.
We review the holographic duals of gauge theories with eight supercharges obtained by adding very few flavors to pure supersymmetric Yang-Mills with sixteen supercharges. Assuming a brane-probe limit, the gravity duals are engineered in terms of probe branes (the so-called flavor brane) in the background of the color branes. Both types of branes intersect on a given subspace in which the matter is confined. The gauge theory dual is thus the corresponding flavoring of the gauge theory with sixteen supercharges. Those theories have in general a non-trivial phase structure; which is also captured…
The addition of fundamental degrees of freedom to a theory which is dual (at low energies) to N=2 SYM in 1+3 dimensions is studied. The gauge theory lives on a stack of Nc D5 branes wrapping an S^2 with the appropriate twist, while the fundamental hypermultiplets are introduced by adding a different set of Nf D5-branes. In a simple case, a system of first order equations taking into account the backreaction of the flavor branes is derived (Nf/Nc is kept of order 1). From it, the modification of the holomorphic coupling is computed explicitly. Mesonic excitations are also discussed.
We study the addition of flavor to the gravity dual of N=4 three-dimensional gauge theories obtained by wrapping $N_c$ D4-branes on a two-cycle of a non-compact Calabi-Yau two-fold. In this setup the flavor is introduced by adding another set of D4-branes that are extended along the non-compact directions of the Calabi-Yau which are normal to the cycle which the color branes wrap. The analysis is performed both in the quenched and unquenched approximations. In this latter case we compute the backreacted metric and we show that it reproduces the running of the gauge coupling. The meson spectrum…
We study strongly coupled ABJM theory on the 3-sphere with massive quenched flavor using the AdS/CFT correspondence. The holographic dual consists of type IIA supergravity with probe D6-branes. The flavor mass is a relevant deformation driving an RG flow whose IR endpoint is pure ABJM theory. At non-zero mass, we find that the theory on the 3-sphere exhibits a quantum phase transition at a critical value of the sphere radius. The transition corresponds to a topology change in the D6-brane embeddings whose dual interpretation is the meson-melting transition. We perform the holographic computati…
We obtain gravity duals to supersymmetric gauge theories in two and three spacetime dimensions with unquenched flavor. The supergravity solutions are generated by a set of color branes wrapping a compact cycle in a Calabi-Yau threefold, together with another set of flavor branes extended along the directions orthogonal to the cycle wrapped by the color branes. We construct supergravity backgrounds which include the backreaction induced by a smeared set of flavor branes, which act as delocalized dynamical sources of the different supergravity fields.
We review recent work on holographic aspects of electric-magnetic dualities in theories that involve conformally coupled scalars and abelian gauge fields in asymptotically AdS4 spaces. Such models are relevant for the holographic description of M-theory. We also briefly comment on some new results on the holographic properties of generalized electric-magnetic duality in gravity.
We present an analysis of the three-flavor holographic model of QCD associated to a $D4/D8$ brane configuration, with symmetry breaking induced by a worldsheet instanton associated to a closed loop connecting $D4-D8-D6-\overline{D8}$. We calculate the electromagnetic and axial couplings of all octet and decuplet baryons, as well as several negative parity excitations, with and without symmetry breaking effects, and demonstrate qualitative and quantitative agreement with many available experimental measurements, with marked improvement over the analogous two-flavor models.
We introduce the strange quark mass to the Sakai-Sugimoto model of holographic QCD. We compute mass shifts in the spectra of three-flavor baryons at the leading order in perturbation in quark masses. Comparison with experimental data shows an agreement only qualitatively.
We introduce a D7-brane probe in AdS_5 x S^5 background in a way that the 4d part of the induced metric on D7-brane becomes 4d de-Sitter space (dS_4) inside AdS_5 instead of 4d Minkowski space. Although supersymmetry is completely broken, we obtain a static configuration and show the absence of dynamical tachyonic modes. Following holographic renormalization we renormalize the Dirac-Born-Infeld action of D7-brane and we completely fix the counter terms including finite contributions from the consistency under various limits. Through the AdS/CFT correspondence we study the chiral condensate and…
We investigate the perturbative (in $g_s N_{D8}$) backreaction of localized D8 branes in D4-D8 systems including in particular the Sakai Sugimoto model. We write down the explicit expressions of the backreacted metric, dilaton and RR form. We find that the backreaction remains small up to a radial value of $u \ll \ell_s/(g_s N_{D8})$, and that the background functions are smooth except at the D8 sources. In this perturbative window, the original embedding remains a solution to the equations of motion. Furthermore, the fluctuations around the original embedding, describing scalar mesons, do not…
We use gauge-gravity duality to compute a new transport coefficient associated with a number Nf of massive N=2 supersymmetric hypermultiplet fields propagating through an N=4 SU(Nc) super-Yang-Mills theory plasma in the limits of large Nc and large 't Hooft coupling, with Nf << Nc. We introduce a baryon number density as well as arbitrary constant electric and magnetic fields, generalizing previous calculations by including a magnetic field with a component parallel to the electric field. We can thus compute all components of the conductivity tensor associated with transport of baryon number c…
The consequences of the Schwinger effect for conductivity is computed for strong coupling systems using holography. The one loop diagram on the flavor brane introduces an $O({λ\over N_c})$ imaginary part in the effective action for a Maxwell flavor gauge field. This in turn introduces a real conductivity in an otherwise insulating phase of the boundary theory. Moreover in certain regions of parameter space the differential conductivity is negative. This is computed in the context of the Sakai-Sugimoto model.
We use gauge-gravity duality to study the transport properties of a finite density of charge carriers in a strongly-coupled theory with non-relativistic symmetry. The field theory is N=4 supersymmetric SU(Nc) Yang-Mills theory in the limit of large Nc and with large 't Hooft coupling, deformed by an irrelevant operator, coupled to a number Nf of massive N=2 supersymmetric hypermultiplets in the fundamental representation of the gauge group, i.e. flavor fields. The irrelevant deformation breaks the relativistic conformal group down to the Schroedinger group, which has non-relativistic scale inv…
We use the Chern-Simons formulation of higher spin theories in three dimensions to study aspects of holographic W-gravity. Concepts which were useful in studies of pure bulk gravity theories, such as the Fefferman-Graham gauge and the residual gauge transformations, which induce Weyl transformations in the boundary theory and their higher spin generalizations, are reformulated in the Chern-Simons language. Flat connections that correspond to conformal and lightcone gauges in the boundary theory are considered.
We construct the gravitational solution of the Witten-Sakai-Sugimoto model by introducing a magnetic field on the flavor brane. With taking into account their backreaction, we re-solve the type IIA supergravity in the presence of the magnetic field. Our calculation shows the gravitational solutions are magnetic-dependent and analytic both in the bubble (confined) and black brane (deconfined) case. We study the dual field theory at the leading order in the ratio of the number of flavors and colors, also in the Veneziano limit. Some physical properties related to the hadronic physics in an exter…
Many-body systems with a conserved U(1) current in (2+1) dimensions may be probed by weakly gauging this current and studying correlation functions of magnetic monopole operators in the resulting dynamical gauge theory. We study such monopole correlations in holographic liquids with fundamental flavor, where the monopole operator is dual to a magnetically charged particle in the bulk. In charge-gapped phases the monopole operator is expected to condense. We show that this condensation is holographically dual to the capping off of the bulk flavor brane and compute the monopole condensate. We ar…
We study certain features of a strongly coupled theory whose gravitational dual is given by two-charge dilatonic black hole in AdS5 which has recently been used to study holographic Fermi liquids. By making use of the gravity description, we have studied conductivity, holographic entanglement entropy and dynamics of a charged scalar field. In particular at low energy we find that the temperature dependence of the real part of the conductivity goes as T^3 and the background is stable against scalar condensations.
We consider universal aspects of a holographic Schwinger effect in general backgrounds with an external homogeneous electric field. The argument is based on the potential analysis developed in our previous work. Under some conditions, there always exists a critical electric field, above which the potential barrier vanishes and the system becomes unstable catastrophically. The critical value agrees with the one obtained from the Dirac-Born-Infeld action. For general confining backgrounds, we show that the Schwinger effect does not occur when the electric field is weaker than the confining strin…
We study a general D-dimensional Schwarzschild-type black brane solution of the Einstein-dilaton theory and derive, by using the holographic renormalization, its thermodynamics consistent with the geometric results. Using the membrane paradigm, we calculate the several hydrodynamic transport coefficients and compare them with the results obtained by the Kubo formula, which shows the self-consistency of the gauge/gravity duality in the relativistic non-conformal theory. In order to understand more about the relativistic non-conformal theory, we further investigate the binding energy, drag force…
We propose a string dual to the SU(Nc) N=4 SYM coupled to Nf massless fundamental flavors in an external magnetic field. The flavors are introduced by homogeneously smeared Nf D7-branes and the external magnetic field via a non-trivial Kalb-Ramond B-field. Our solution is perturbative in a parameter that counts the number of internal flavor loops. In the limit of vanishing B-field the background reduces to the supersymmetric one obtained in hep-th/0612118. We introduce an additional probe D7--brane and in the supersymmetric limit of vanishing B-field perform a holographic renormalization of it…
We generalize the description of baryons as instantons of Sakai-Sugimoto model to the case where the flavor branes are non-anti-podal. The later corresponds to quarks with a "string endpoint mass". We show that the baryon vertex is located on the flavor branes and hence the generalized baryons also associate with instantons. We calculate the baryon mass spectra, the isoscalar and axial mean square radii, the isoscalar and isovector magnetic moments and the axial coupling as a function of the mass scale M_{KK} and the location ζof the tip of U-shaped flavor D8-branes. We determine the values of…
We study dynamical baryons in the holographic QCD model of Sakai and Sugimoto in the case of three flavors and with special interest in the construction of the Chern-Simons (CS) term. The baryon classical solution in this model is given by the BPST instanton, and we carry out the collective coordinate quantization of the solution. The CS term should give rise to a first class constraint which selects baryon states with right spins. However, the original CS term written in terms of the CS 5-form does not work. We instead propose a new CS term which is gauge invariant and is given as an integral…
We demonstrate a holographic realization of color-flavor locking phase, using N=4 SU(Nc) SYM coupled to N=2 Nf fundamental hypermultiplets as an example. The gravity dual consists of Nc D3-branes and Nf D7-branes with world volume gauge field representing the baryon density. Treating a small number \tilde{N}c << Nc of D3-branes as Yang-Mills instantons on the D7-branes, we consider possible potential(s) on their moduli space or equivalently the Higgs branch. We show that a non-trivial potential can be generated by including the backreaction of the baryonic density on the D7-branes, this dynami…
We study the holographic dual of the Higgs branch of N=4 SYM in four dimensions coupled to quenched fundamental matter. The fundamentals are added via flavor D7-branes and the Higgs phase is obtained when the color D3-branes and the flavor D7-branes recombine with each other. The holographic dual consists of D7-brane probes in the background generated by the color D3-branes. In this supergravity dual the Higgs phase is realized by switching on a selfdual field strength on the worldvolume of the D7-branes. A complementary microscopic description in terms of dielectric D3-branes is also possible…
In earlier work the evolution operator for the exact RG equation was mapped to a field theory in Euclidean AdS. This gives a simple way of understanding AdS/CFT. We explore aspects of this map by studying a simple example of a Schroedinger equation for a free particle with time dependent mass. This is an analytic continuation of an ERG like equation. We show for instance that it can be mapped to a harmonic oscillator. We show that the same techniques can lead to an understanding of dS/CFT too.
We study the holographic dual of flavors in a Chern-Simons matter theory at non-zero temperature, realized as D6-branes in the type IIA black hole dual in the ABJM background geometry. We consider both massive and massless flavors. The former are treated in the quenched approximation, whereas the massless ones are considered as dynamical objects and their backreaction on the geometry is included in the black hole background. We compute the holographically renormalized action of the probe by imposing several physical conditions. In the limit of massless flavors the free energy and entropy of th…
We review the construction of gravitational solutions holographically dual to N=1 quiver gauge theories with dynamical flavor multiplets. We focus on the D3-D7 construction and consider the finite temperature, finite quark chemical potential case where there is a charged black hole in the dual solution. Discussed physical outputs of the model include its thermodynamics (with susceptibilities) and general hydrodynamic properties.
In the framework of six-dimensional conformal field theories with ${\cal N}=(1,0)$ supersymmetry we develop the map between the holographic description, the field theoretical description and the associated Hanany-Witten set-ups. General expressions that calculate various observables are presented. The study of string solitons singles out a special background of Massive IIA on which we show (by explicitly finding a Lax pair) that the Neveu-Schwarz part of the string sigma model is classically integrable. We study the particular dual conformal field theory and compute some of its observables.
We study the holographic description of ${\cal N}=2$ Super Conformal Field Theories in four dimensions first given by Gaiotto and Maldacena. We present new expressions that holographically calculate characteristic numbers of the CFT and associated Hanany-Witten set-ups, or more dynamical observables, like the central charge. A number of examples of varying complexity are studied and some proofs for these new expressions are presented. We repeat this treatment for the case of the marginally deformed Gaiotto-Maldacena theories, presenting an infinite family of new solutions and compute some of i…
In this letter we put AdS/CFT dualities involving probe branes to a precision test. On the holographic side we use a new class of supersymmetric D7-brane embeddings into AdS$_5\times$S$^5$, which allow to describe N=4 SYM coupled to massive N=2 supersymmetric flavors on S$^4$. With these embeddings we can compare holographic results to a field theory analysis of the free energy using supersymmetric localization. Localization allows us to get results at strong coupling, and hence to compare in detail to AdS/CFT. We find analytically matching results: a phase transition at the same critical mass…
Gravity solutions describing the Witten-Sakai-Sugimoto model of holographic QCD with dynamical flavors are presented. The field theory is studied in the Veneziano limit, at first order in the ratio of the number of flavors and colors. The gravity solutions are analytic and dual to the field theory either in the confined, low temperature phase or in the deconfined, high temperature phase with small baryonic charge density. The phase diagram and the flavor contributions to vacuum (e.g. string tension and hadron masses) and thermodynamical properties of the dual field theory are then deduced. The…
The content of this paper includes studying holographical and thermodynamical aspects of dyonic black holes in the presence of massive gravity. For the first part of paper, thermodynamical properties of the bulk which includes black holes are studied and the main focus is on critical behavior. It will be shown that the existence of massive gravitons introduces remnant for temperature after evaporation of black holes, van der Waals phase transition for non-spherical black holes and etc. The consistency of different thermodynamical approaches toward critical behavior of the black holes is presen…
We consider the noncommutative deformation of the Sakai--Sugimoto model at finite temperature and finite baryon chemical potential. The space noncommutativity is possible to have an influence on the flavor dynamics of the QCD. The critical temperature and critical value of the chemical potential are modified by the space noncommutativity. The influence of the space noncommutativity on the flavor dynamics of the QCD is caused by the Wess--Zumino term in the effective action of the D8-branes. The intermediate temperature phase, in which the gluons deconfine but the chiral symmetry remains broken…
We find two systems via holography that exhibit quantum Berezinskii-Kosterlitz-Thouless (BKT) phase transitions. The first is the ABJM theory with flavor and the second is a flavored (1,1) little string theory. In each case the transition occurs at nonzero density and magnetic field. The BKT transition in the little string theory is the first example of a quantum BKT transition in (3+1) dimensions. As in the "original" holographic BKT transition in the D3/D5 system, the exponential scaling is destroyed at any nonzero temperature and the transition becomes second order. Along the way we constru…
We study the effects of an external magnetic field on the properties of the quasiparticle spectrum of the class of 2+1 dimensional strongly coupled theories holographically dual to charged AdS$_4$ black holes at zero temperature. We uncover several interesting features. At certain values of the magnetic field, there are multiple quasiparticle peaks representing a novel level structure of the associated Fermi surfaces. Furthermore, increasing magnetic field deforms the dispersion characteristics of the quasiparticle peaks from non-Landau toward Landau behaviour. At a certain value of the magnet…
We examine the static potential in the presence of flavors in the perturbative backreacted D4/D8 system from localized D8 branes, focusing in particular on the Sakai-Sugimoto model. For the case of long strings we find the flavor corrections to the static potential which are of exponential form. We then investigate shorter Wilson loops and express their energy analytically in terms of the lengths of two neighboring Wilson loops. Moreover, we find that the static force for all the cases in the backreacted background is reduced compared to one in the probe limit, as expected due to screening eff…
We study baryons in holographic QCD corresponding to 1+1 dimensional single-flavor ($N_f$=1) QCD for the first time. We formulate 1+1 QCD using an $S^1$-compactified D2/D8/$\overline{\rm D8}$ branes in the superstring theory, and describe the baryon as a topological configuration in 1+1 $N_f$=1 QCD, corresponding to $Π_1({\rm U(1)})={\bf Z}$. Unlike 1+3 QCD with $N_f \ge 2$, however, we find that the low-dimensional baryonic soliton is generally unstable against a scale transformation/variation and swells infinitely in 1+1 $N_f$=1 QCD at the leading of large $N_c$. We thus point out a serious …
We consider the generalization of the S-duality transformation previously investigated in the context of the FQHE and s-wave superconductivity to p-wave superconductivity in 2+1 dimensions in the framework of the AdS/CFT correspondence. The vector Cooper condensate transforms under the S-duality action to the pseudovector condensate at the dual side. The 3+1-dimensional Einstein-Yang-Mills theory, the holographic dual to p-wave superconductivity, is used to investigate the S-duality action via the AdS/CFT correspondence. It is shown that in order to implement the duality transformation, chemic…
We study the dependence of the chiral condensate on external magnetic field in the context of holographic QCD at large number of flavors. We consider a holographic QCD model where the flavor degrees of freedom fully backreact on the color dynamics. Perturbative QCD calculations have shown that $B$ acts constructively on the chiral condensate, a phenomenon called "magnetic catalysis". In contrast, recent lattice calculations show that, depending on the number of flavors and temperature, the magnetic field may also act destructively, which is called "inverse magnetic catalysis". Here we show tha…
We study baryons of arbitrary isospin in a stringy holographic QCD model. In this D4-D8 holographic setting, the flavor symmetry is promoted to a gauge symmetry in the bulk, and produces, as KK modes of the gauge field, pions and spin one mesons of low energy QCD. Baryons of arbitrary isospins are represented as instanton solitons with isospin and spin quantum numbers locked, in a manner similar to the Skyrmion model. The soliton picture leads to a natural effective field theory of arbitrary baryons interacting with mesons. Couplings of baryons to axial mesons, including pions, are dominated i…
We are looking for a holographic explanation of nuclear forces, especially the attractive forces. Recently, the repulsive hard core of a nucleon-nucleon potential was obtained in the Sakai-Sugimoto model, and we show that a generalized version of that model -- with an asymmetric configuration of the flavor D8 branes -- also has an attractive potential. While the repulsive potential stems from the Chern-Simons interactions of the U(2) flavor gauge fields in 5D, the attractive potential is due to a coupling of the gauge fields to a scalar field describing fluctuations of the flavor branes' geome…
With the construction of the Witten-Sakai-Sugimoto model in the D0-D4 background, we systematically investigate the holographic baryon spectrum in the case of three flavors. The background geometry in this model is holographically dual to $U\left(N_{c}\right)$ Yang-Mills theory in large $N_{c}$ limit involving an excited state with a nonzero $θ$ angle or glue condensate $\left\langle \mathrm{Tr}\mathcal{F}\wedge\mathcal{F}\right\rangle =8π^{2}N_{c}\tildeκ$, which is proportional to the charge density of the smeared D0-branes through a parameter $b$ or $\tildeκ$. The classical solution of baryo…
In this thesis we explore general aspects of the entanglement entropy (EE) for Conformal Field Theories (CFTs) dual to Cubic Curvature Gravity. We derived a covariant expression for the EE by using a scheme inherited from the bulk renormalization method through extrinsic counterterms. We evaluate this functional in different entangling regions to calculate CFT data. In particular, we compute the $t_4$ coefficient of the 3-point function of the stress-tensor correlator by considering a deformed entangling region. We observe that there is a discrepancy between the outcomes attained through the e…
In this paper, we study the holography of quasi-topological gravity in several aspects. We redo the calculation of shear viscosity on the boundary CFT with a new method which is associated with conserved Noether current and show that it has only one mode explicitly. Then we study the butterfly effect in AdS planar black hole and find it has two butterfly velocity modes because of the quasi-topological term. We obtain new black hole solution through introducing matter fields. We calculate the thermoelectric DC conductivity with momentum dissipation in quasi-topological gravity and find its resu…
We construct backreacted D3/D7 supergravity backgrounds which are dual to four-dimensional N=1 and N=2 supersymmetric Yang-Mills at large N_c with flavor quarks in the fundamental representation of SU(N_c). We take into account the backreaction of D7-branes on either AdS(5) x S(5) or AdS(5) x T^{1,1}, or more generically on backgrounds where the space transverse to the D3-branes is Kaehler. The construction of the backreacted geometry splits into two stages. First we determine the modification of the six-dimensional space transverse to the D3 due to the D7, and then we compute the warp factor …
We extend the two-flavor hard-wall holographic model of Erlich, Katz, Son and Stephanov [Phys.\ Rev.\ Lett.\ {\bf 95}, 261602 (2005)] to four flavors to incorporate strange and charm quarks. The model incorporates chiral and flavor symmetry breaking and provides a reasonable description of masses and weak decay constants of a variety of scalar, pseudoscalar, vector and axial-vector strange and charmed mesons. In particular, we examine flavor symmetry breaking in the strong couplings of the $ρ$ meson to the charmed $D$ and $D^{*}$ mesons. We also compute electromagnetic form factors of the $π$,…
In this work I explore theoretical and phenomenological implications of chemical potentials and charge densities inside a strongly coupled thermal plasma, using the gauge/gravity correspondence. Strong coupling effects discovered in this model theory are interpreted geometrically and may be taken as qualitative predictions for heavy ion collisions at RHIC and LHC. In particular I examine the thermodynamics, spectral functions, transport coefficients and the phase diagram of the strongly coupled plasma. For example stable mesons, which are the analogs of the QCD Rho-mesons, are found to survive…
Quark flavors in hot and dense holographic QCD: setup and comparison to data
Asia Pacific Center for Theoretical Physics（亚太理论物理中心）；Department of Physics, Pohang University of Science and Technology（浦项科技大学物理系）；Institute of Theoretical Physics, Chinese Academy of Sciences（中国科学院理论物理研究所）；Institute for Theoretical Physics, University of Heidelberg（海德堡大学理论物理研究所）
