Results 1  10
of
27
Dielectric branes
 JHEP
, 1999
"... Preprint typeset in JHEP style PAPER VERSION ..."
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Holographic decays of largespin mesons
"... Abstract: We study the decay process of largespin mesons in the context of the gauge/string duality, using generic properties of confining backgrounds and systems with flavour branes. In the string picture, meson decay corresponds to the quantummechanical process in which a string rotating on the ..."
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Cited by 26 (8 self)
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Abstract: We study the decay process of largespin mesons in the context of the gauge/string duality, using generic properties of confining backgrounds and systems with flavour branes. In the string picture, meson decay corresponds to the quantummechanical process in which a string rotating on the IR “wall ” fluctuates, touches a flavour brane and splits into two smaller strings. This process automatically encodes flavour conservation as well as the Zweig rule. We show that the decay width computed in the string picture is in remarkable agreement with the decay width obtained using the phenomenological Lund model. Keywords: AdS/CFT, meson decay, spinning strings. Contents
Interpolating between low and high energy QCD via a 5D YangMills model
, 2005
"... We describe the Goldstone bosons of massless QCD together with an infinite number of spin1 mesons. The field content of the model is SU(Nf) × SU(Nf) YangMills in a compact extradimension. Electroweak interactions reside on one brane. Breaking of chiral symmetry occurs due to the boundary condi ..."
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Cited by 25 (3 self)
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We describe the Goldstone bosons of massless QCD together with an infinite number of spin1 mesons. The field content of the model is SU(Nf) × SU(Nf) YangMills in a compact extradimension. Electroweak interactions reside on one brane. Breaking of chiral symmetry occurs due to the boundary conditions on the other brane, away from our world, and is therefore spontaneous. Our implementation of the holographic recipe maintains chiral symmetry explicit throughout. For intermediate energies, we extract resonance couplings. These satisfy sum rules due to the 5D nature of the model. These sum rules imply, when taking the highenergy limit, that perturbative QCD constraints are satisfied. We also illustrate how the 5D model implies a definite prescription for handling infinite sums over 4D resonances. Taking the lowenergy limit, we recover the chiral expansion and the corresponding nonlocal order parameters. All local order parameters are introduced separately.
Toward a Holographic Model of Superconducting Fermions
, 2008
"... We use the AdS/CFT correspondence to study N = 4 supersymmetric SU(Nc) YangMills theory, in the limits of large Nc and large ’t Hooft coupling, coupled to a number Nf of massless hypermultiplet fields in the fundamental representation of the gauge group. We identify a U(1) subgroup of the Rsymmet ..."
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Cited by 14 (0 self)
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We use the AdS/CFT correspondence to study N = 4 supersymmetric SU(Nc) YangMills theory, in the limits of large Nc and large ’t Hooft coupling, coupled to a number Nf of massless hypermultiplet fields in the fundamental representation of the gauge group. We identify a U(1) subgroup of the Rsymmetry under which the fermions in the hypermultiplet are charged but the scalars are not. All the hypermultiplet fields are also charged under a U(1) baryon number symmetry. We introduce an external magnetic field for the baryon number U(1), which triggers the spontaneous breaking of the U(1) Rsymmetry, and we then introduce a chemical potential for the U(1) Rcharge, producing a state with a nonzero density of the U(1) Rcharge. The system should then exhibit superconductivity of the U(1) Rcharge. The dual supergravity description is a number Nf of D7branes in AdS5 × S 5 with angular momentum on the S 5 and a worldvolume magnetic field. We study the zerotemperature thermodynamics of the system, and find that for sufficiently large magnetic field the system prefers to be in the symmetrybroken phase. For smaller magnetic fields we find a discontinuous free energy, indicating that our gravitational setup does not capture all equilibrium states of the field theory.
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
Decoupling of high dimension operators from the low energy sector in holographic models,” arXiv:1304.3458 [hepth
"... We study the decoupling of high dimension operators from the the description of the lowenergy spectrum in theories where conformal symmetry is broken by a single scale, which we refer to as ‘broken CFTs’. Holographic duality suggests that this decoupling occurs in generic backgrounds. We show how t ..."
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We study the decoupling of high dimension operators from the the description of the lowenergy spectrum in theories where conformal symmetry is broken by a single scale, which we refer to as ‘broken CFTs’. Holographic duality suggests that this decoupling occurs in generic backgrounds. We show how the decoupling of high mass states in the (d + 1)dimensional bulk relates to the decoupling of high energy states in the ddimensional broken CFT. In other words, we explain why both high dimension operators and high mass states in the CFT decouple from the lowenergy physics of the mesons and glueballs. In many cases, the decoupling can occur exponentially fast in the dimension of the operator. Holography motivates a new kind of form factor proportional to the two point function between broken CFT operators with very different scaling dimensions. This new notion of decoupling can provide a systematic justification for holographic descriptions of QCD and condensed matter systems with only light degrees of freedom in the bulk. ar X iv
Holographic flavor in theories with eight supercharges
, 2007
"... We review the holographic duals of gauge theories with eight supercharges obtained by adding very few flavors to pure supersymmetric YangMills with sixteen supercharges. Assuming a braneprobe limit, the gravity duals are engineered in terms of probe branes (the socalled flavor brane) in the backg ..."
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Cited by 1 (0 self)
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We review the holographic duals of gauge theories with eight supercharges obtained by adding very few flavors to pure supersymmetric YangMills with sixteen supercharges. Assuming a braneprobe limit, the gravity duals are engineered in terms of probe branes (the socalled 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 nontrivial phase structure; which is also captured in a beautiful way by the gravity dual. Along the lines of the gauge/gravity duality, we review also some of the results on the meson spectrum in the different phases of the theories.
Spectral Flow on the Higgs Branch and AdS/CFT duality
, 2005
"... We use AdS/CFT duality to study the large Nc limit of the meson spectrum on the Higgs branch of a strongly coupled, N = 2 supersymmetric SU(Nc) gauge theory with Nf = 2 fundamental hypermultiplets. In the dual supergravity description, the Higgs branch is described by SU(2) instanton configurations ..."
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We use AdS/CFT duality to study the large Nc limit of the meson spectrum on the Higgs branch of a strongly coupled, N = 2 supersymmetric SU(Nc) gauge theory with Nf = 2 fundamental hypermultiplets. In the dual supergravity description, the Higgs branch is described by SU(2) instanton configurations on D7branes in an AdS background. We compute the spectral flow parameterized by the size of a single instanton. In the large Nc limit, there is a sense in which the flow from zero to infinite instanton size, or Higgs VEV, can be viewed as a closed loop. We show that this flow leads to a nontrivial rearrangement of the spectrum.