arXiv subjects

Chanyong Park

Publications and source records attributed to Chanyong Park.

At least 73 records · Page 4Linked to original sources

arXiv2013

Inside and outside stories of black-branes in anti de Sitter space

In this paper, we investigate the dynamics inside and outside of black-branes in anti de Sitter space by numerical simulations using double-null formalism. We prepare a charged planar matter shell which, due to a negative cosmological constant, collapses and dynamically forms a black-brane with an apparent horizon, a singularity and a Cauchy horizon. The gravitational collapse cannot form a naked overcharged black-brane and hence weak cosmic censorship is safe. Although mass inflation occurs, the effect is much milder than in the case of charged black holes; hence, strong cosmic censorship seems not to be safe. We observed the scalar field dynamics outside the horizon. There should remain a non-trivial scalar field combination - 'charge cloud' - between the horizon and the boundary. This can give some meaning in terms of the AdS/CFT correspondence.

hep-th↗

arXiv2013

Holographic meson mass splitting in the Nuclear Matter

We study the holographic light meson spectra and their mass splitting in the nuclear medium. In order to describe the nuclear matter, we take into account the thermal charged AdS geometry with two flavor charges, which can be reinterpreted as the number densities of proton and neutron after some field redefinitions. We show that the meson mass splitting occurs when there exists the density difference between proton and neutron. Depending on the flavor charge, the mass of the positively (negatively) charged meson increases (decreases) as the density difference increases, whereas the neutral meson mass is independent of the density difference. In the regime of the large nucleon density with a relatively large number difference between proton and neutron, we find that negatively charged pion becomes massless in the nuclear medium, so the pion condensate can occur. We also investigate the binding energy of a heavy quarkonium in the nuclear medium, in which the binding energy of a heavy quarkonium becomes weaker as the density difference increases.

hep-th↗

arXiv2013

Holographic aspects of a relativistic non-conformal theory

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 and holographic entanglement entropy of the relativistic non-conformal theory.

hep-th↗

arXiv2013

Transport in non-conformal holographic fluids

We have considered non-conformal fluid dynamics whose gravity dual is a certain Einstein dilaton system with Liouville type dilaton potential, characterized by an intrinsic parameter $η$. We have discussed the Hawking-Page transition in this framework using hard-wall model and it turns out that the critical temperature of the Hawking-Page transition encapsulates a non-trivial dependence on $η$. We also obtained transport coefficients such as AC conductivity, shear viscosity and diffusion constant in the hydrodynamic limit, which show non-trivial $η$ dependent deviations from those in conformal fluids, although the ratio of the shear viscosity to entropy density is found to saturate the universal bound. Some of the retarded correlators are also computed in the high frequency limit for case study.

hep-th↗

arXiv2013

Correlation functions of the ABJM model

In the ABJM model, we study the three-point function of two heavy operators and an (ir)relevant one. Following the AdS/CFT correspondence, the structure constant in the large 't Hooft coupling limit can be factorized into two parts. One is the structure constant with a marginal operator, which is fully determined by the physical quantities of heavy operator and gives rise to the consistent result with the RG analysis. The other can be expressed as the universal form depending only on the conformal dimension of an (ir)relevant operator. We also investigate the new size effect of a circular string dual to a certain closed spin chain.

hep-th↗

arXiv2013

Correlators of massive string states with conserved currents

We calculate correlation functions of the R-current or the stress-energy tensor T_{μν} with two non-protected operators dual to generic massive string states with rotation in S^5, in the context of the AdS/CFT correspondence. Field theory Ward identities make predictions about the all-loop behaviour of these correlators. In particular, they restrict the fusion coefficient to be proportional to the R-charge of the operators or to their dimension, respectively, with certain coefficients of proportionality. We reproduce these predictions, at strong coupling, using string theory. Furthermore, we point out that the recently observed strong coupling factorisation of 4-point correlators is consistent with conformal symmetry and puts constraints on the strong coupling expressions of 4-point correlators involving R-currents or the stress-energy tensor.

hep-th↗

arXiv2012

Non-conformal Hydrodynamics in Einstein-dilaton Theory

In the Einestein-dilaton theory with a Liouville potential parameterized by $η$, we find a Schwarzschild-type black hole solution. This black hole solution, whose asymptotic geometry is described by the warped metric, is thermodynamically stable only for $0 \le η< 2$. Applying the gauge/gravity duality, we find that the dual gauge theory represents a non-conformal thermal system with the equation of state depending on $η$. After turning on the bulk vector fluctuations with and without a dilaton coupling, we calculate the charge diffusion constant, which indicates that the life time of the quasi normal mode decreases with $η$. Interestingly, the vector fluctuation with the dilaton coupling shows that the DC conductivity increases with temperature, a feature commonly found in electrolytes.

hep-th↗

arXiv2012

Chern-Simons effect on the dual hydrodynamics in the Maxwell-Gauss-Bonnet gravity

Following the previous work 1103.3773, we give a more general and systematic discussion on the Chern-Simons effect in the 5-dimensional Maxwell-Gauss-Bonnet gravity. After constructing the first order perturbative black brane solution, we extract the stress tensor and charge current of dual fluid. From these results, we find out the dependence of some transport coefficients on the Gauss-Bonnet coupling $α$ and Chern-Simons coupling $κ_{cs}$. We also show that the new anomalous term can provide an additional contribution to the anomalous chiral magnetic conductivity.

hep-th↗

arXiv2011

Holographic Meson Spectra in the Dense Medium with Chiral Condensate

We study two $1/N_c$ effects on the meson spectra by using the AdS/CFT correspondence where the $1/N_c$ corrections from the chiral condensate and the quark density are controlled by the gravitational backreaction of the massive scalar field and U(1) gauge field respectively. The dual geometries with zero and nonzero current quark masses are obtained numerically. We discuss meson spectra and binding energy of heavy quarkonium with the subleading corrections in the hard wall model.

hep-th↗

arXiv2011

Holographic Symmetry Energy of the Nuclear Matter

We calculate the symmetry energy of the nuclear matter by using the bottom-up approach, so called hard wall model. To consider the nuclear matter, we introduce the isospin for u- and d-quarks. We find that in the hard wall model, the symmetry energy of the nuclear matter is proportional to the square of nucleon density. We also study the symmetry energy of the quark matter in the deconfining phase. Finally, we investigate the effect of the symmetry energy on the Hawking-Page transition and show that at the given quark density, the Hawking-Page transition temperature decreases due to the symmetry energy.

hep-th↗

arXiv2011

Holographic superconductor in the exact hairy black hole

We study the charged black hole of hyperbolic horizon with scalar hair (charged Martinez-Troncoso-Zanelli: CMTZ black hole) as a model of analytic hairy black hole for holographic superconductor. For this purpose, we investigate the second order phase transition between CMTZ and hyperbolic Reissner-Nordström-AdS (HRNAdS) black holes. However, this transition unlikely occur. As an analytic treatment for holographic superconductor, we develop superconductor in the bulk and superfluidity on the boundary using the CMTZ black hole below the critical temperature. The presence of charge destroys the condensates around the zero temperature, which is in accord with the thermodynamic analysis of the CMTZ black hole.

hep-th↗

arXiv2011

A Holographic Model of Strange Metals

We give a review on our recent work arXiv:1006.0779 [hep-th] and arXiv:1006.1719 [hep-th], in which properties of holographic strange metals were investigated. The background is chosen to be anisotropic scaling solution in Einstein-Maxwell-Dilaton theory with a Liouville potential. The effects of bulk Maxwell field, an extra U(1) gauge field and probe D-branes on the DC conductivity, the DC Hall conductivity and the AC conductivity are extensively analyzed. We classify behaviors of the conductivities according to the parameter ranges in the bulk theory and characterize conditions when the holographic results can reproduce experimental data.

hep-th↗

arXiv2011

Finite size effect on the magnon's correlation functions

We calculate the finite size correction on the three-point correlation function between two giant magnons and one marginal operator. We also check that the structure constant in the string set-up is exactly the same as one of the RG analysis in the gauge theory.

hep-th↗

arXiv2011

Yang-Mills Instantons from Gravitational Instantons

We show that every gravitational instantons are SU(2) Yang-Mills instantons on a Ricci-flat four manifold although the reverse is not necessarily true. It is shown that gravitational instantons satisfy exactly the same self-duality equation of SU(2) Yang-Mills instantons on the Ricci-flat manifold determined by the gravitational instantons themselves. We explicitly check the correspondence with several examples and discuss their topological properties.

hep-th↗

arXiv2011

Correlation functions of magnon and spike

After considering a solitonic string moving in the Poincare $AdS$ and two-dimensional sphere, we calculate the two-point correlation function of magnon and spike in the semi-classical limit without any explicit solution. We also calculate the three-point correlation functions between two heavy and one light operators. We find that the coupling between two heavy and one light operators in the string side is the exactly same as one obtained from the gauge theory by using the RG analysis.

hep-th↗

arXiv2011

Correlation function of dyonic strings

We investigate the two- and three-point correlation functions of the dyonic magnon and spike, which correspond to the solitonic string moving in the Poincare AdS and three-dimensional sphere. We show that the coupling between two dyonic magnons or spikes together with a marginal scalar operator in the string theory is exactly the same as one obtained by the RG analysis in the gauge theory.

hep-th↗

arXiv2011

Conductivity in the anisotropic background

By using the gauge/gravity duality, we investigate the dual field theories of the anisotropic backgrounds, which are exact solutions of Einstein-Maxwell-dilaton theory with a Liouville potential. When we turn on the bulk gauge field fluctuation $A_x$ with a non-trivial dilaton coupling, the AC conductivity of this dual field theory is proportional to the frequency with an exponent depending on parameters of the anisotropic background. In some parameter regions, we find that this conductivity can have the negative exponent like the strange metal. In addition, we also investigate another U(1) gauge field fluctuation, which is not coupled with a dilaton field. We classify all possible conductivities of this system and find that the exponent of the conductivity is always positive.

hep-th↗

arXiv2010

Meson spectra in a gluon condensate background

We study the spectra of light mesons as well as the dissociation of a quarkonium and monopole-anti monopole bound state in a gluon condensate background. In order to describe the confining phase we introduce an IR cutoff in two ways, namely the hard wall and the braneless approaches. We find that the meson spectra strongly depend on the gluon condensate in the braneless approach, while they do not in the hard wall model. The latter result appears to be a more probable feature of QCD.

hep-ph↗