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50
Towards strange metallic holography
"... We initiate a holographic model building approach to ‘strange metallic ’ phenomenology. Our model couples a neutral Lifshitzinvariant quantum critical theory, dual to a bulk gravitational background, to a finite density of gapped probe charge carriers, dually described by Dbranes. In the physical ..."
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We initiate a holographic model building approach to ‘strange metallic ’ phenomenology. Our model couples a neutral Lifshitzinvariant quantum critical theory, dual to a bulk gravitational background, to a finite density of gapped probe charge carriers, dually described by Dbranes. In the physical regime of temperature much lower than the charge density and gap, we exhibit anomalous scalings of the temperature and frequency dependent conductivity. Choosing the dynamical critical exponent z appropriately we can match the nonFermi liquid scalings, such as linear resistivity, observed in strange metal regimes. As part of our investigation we outline three distinct string theory realizations of Lifshitz geometries: from F theory, from polarised branes, and from a gravitating charged Fermi gas. We also identify general features of renormalisation group flow in Lifshitz theories, such as the appearance of relevant chargecharge interactions when z ≥ 2. We outline a program to extend this model building approach to other anomalous observables of
Towards a Holographic Model of ColorFlavor Locking Phase
, 909
"... Abstract: We demonstrate a holographic realization of colorflavor locking phase, using N = 4 SU(Nc) SYM coupled to N = 2 Nf fundamental hypermultiplets as an example. The gravity dual consists of Nc D3branes and Nf D7branes with world volume gauge field representing the baryon density. Treating a ..."
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Abstract: We demonstrate a holographic realization of colorflavor locking phase, using N = 4 SU(Nc) SYM coupled to N = 2 Nf fundamental hypermultiplets as an example. The gravity dual consists of Nc D3branes and Nf D7branes with world volume gauge field representing the baryon density. Treating a small number Ñc ⊂ Nc of D3branes as YangMills instantons on the D7branes, we consider possible potential(s) on their moduli space or equivalently the Higgs branch. We show that a nontrivial potential can be generated by including the backreaction of the baryonic density on the D7branes, this dynamically drives the instantons ( = D3branes) into dissolution. We interpret this as a colorflavor locking since the size of the instanton is the squark vev, and study the symmetry breaking patterns. Extending to finite temperature setup, we demonstrate that colorflavor locking persists, and the thermal
Gauge/String Duality, Hot QCD and Heavy Ion Collisions
, 2014
"... Over the last decade, both experimental and theoretical advances have brought the need for strong coupling techniques in the analysis of deconfined QCD matter and heavy ion collisions to the forefront. As a consequence, a fruitful interplay has developed between analyses of stronglycoupled nonabel ..."
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Cited by 10 (0 self)
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Over the last decade, both experimental and theoretical advances have brought the need for strong coupling techniques in the analysis of deconfined QCD matter and heavy ion collisions to the forefront. As a consequence, a fruitful interplay has developed between analyses of stronglycoupled nonabelian plasmas via the gauge/string duality (also referred to as the AdS/CFT correspondence) and the phenomenology of heavy ion collisions. We review some of the main insights gained from this interplay to date. To establish a common language, we start with an introduction to heavy ion phenomenology and finitetemperature QCD, and a corresponding introduction to important concepts and techniques in the gauge/string duality. These introductory sections are written for nonspecialists, with the goal of bringing readers ranging from beginning graduate students to experienced practitioners of either QCD or gauge/string duality to the point that they understand enough about both fields that they can then appreciate their interplay in all appropriate contexts. We then review the current stateofthe art in the application of the duality to the description of the dynamics of strongly coupled plasmas, with emphases that include: its thermodynamic, hydrodynamic and transport properties; the way it both modifies the dynamics of, and is perturbed by, highenergy or heavy quarks passing through it; and the physics of quarkonium mesons within it. We seek throughout to stress the lessons that can be extracted from these computations for heavy ion physics as well as to discuss future directions and open problems for the field. ar X iv
Quark Soup al dente: Applied Superstring Theory,” arXiv:0804.2423 [hepth
"... Abstract. In recent years, experiments have discovered an exotic new state of matter known as the strongly coupled quarkgluon plasma (sQGP). At present, it seems that standard theoretical tools, such as perturbation theory and lattice gauge theory, are poorly suited to understand this new phase. Ho ..."
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Cited by 9 (0 self)
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Abstract. In recent years, experiments have discovered an exotic new state of matter known as the strongly coupled quarkgluon plasma (sQGP). At present, it seems that standard theoretical tools, such as perturbation theory and lattice gauge theory, are poorly suited to understand this new phase. However, recent progress in superstring theory has provided us with a theoretical laboratory for studying very similar systems of strongly interacting hot nonabelian plasmas. This surprising new perspective extracts the fluid properties of the sQGP from physical processes in a black hole spacetime. Hence we may find the answers to difficult particle physics questions about the sQGP from straightforward calculations in classical general relativity. Quark Soup al dente 2 1.
Comments on Fermi Liquid from Holography
, 2008
"... We investigate the signatures of Fermi liquid formation in the N = 4 super YangMills theory coupled to fundamental hypermultiplet at nonvanishing chemical potential for the global U(1) vector symmetry. At strong ’t Hooft coupling the system can be analyzed in terms of the D7 brane dynamics in AdS5 ..."
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Cited by 9 (1 self)
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We investigate the signatures of Fermi liquid formation in the N = 4 super YangMills theory coupled to fundamental hypermultiplet at nonvanishing chemical potential for the global U(1) vector symmetry. At strong ’t Hooft coupling the system can be analyzed in terms of the D7 brane dynamics in AdS5 ×S5 background. The phases with vanishing and finite charge density are separated at zero temperature by a quantum phase transition. In case of vanishing hypermultiplet mass, Karch, Son and Starinets discovered a gapless excitation whose speed equals the speed of sound. We find that this zero sound mode persists to all values of the hypermultiplet mass, and its speed vanishes at the point of phase transition. The value of critical exponent and the ratio of the velocities of zero and first sounds are consistent with the predictions of Landau Fermi liquid theory at strong coupling.
External Fields and the Dynamics of Fundamental Flavours IN HOLOGRAPHIC DUALS OF LARGE N GAUGE THEORIES
, 2010
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Critical Exponents from AdS/CFT with Flavor
, 906
"... Abstract: We use the AdS/CFT correspondence to study the thermodynamics of massive N = 2 supersymmetric hypermultiplet flavor fields coupled to N = 4 supersymmetric SU(Nc) YangMills theory, formulated on curved fourmanifolds, in the limits of large Nc and large ’t Hooft coupling. The gravitational ..."
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Abstract: We use the AdS/CFT correspondence to study the thermodynamics of massive N = 2 supersymmetric hypermultiplet flavor fields coupled to N = 4 supersymmetric SU(Nc) YangMills theory, formulated on curved fourmanifolds, in the limits of large Nc and large ’t Hooft coupling. The gravitational duals are probe Dbranes in global thermal AdS. These Dbranes may undergo a topologychanging transition in the bulk. The Dbrane embeddings near the point of the topology change exhibit a scaling symmetry. The associated scaling exponents can be either real or complexvalued. Which regime applies depends on the dimensionality of a collapsing submanifold in the critical embedding. When the scaling exponents are complexvalued, a firstorder transition associated with the flavor fields appears in the dual field theory. Real scaling exponents are expected to be associated with a continuous transition in the dual field theory. For one example with real exponents, the D7brane, we study the transition in detail. We find two field theory observables that diverge at the critical point, and we compute the associated critical exponents. We also present analytic and numerical evidence that the transition expresses itself in the meson spectrum as a nonanalyticity at the critical point. We argue that the transition we study is a true phase