arXiv subjects

Chanyong Park

Publications and source records attributed to Chanyong Park.

At least 55 records · Page 3Linked to original sources

arXiv2017

Anisotropic Dyonic Black Brane and its Effects on Hydrodynamics

We construct $SL(2,R)$ invariant in anisotropic medium, with a dual anisotropic charged black hole geometry in massive gravity. We show how to obtain $SL(2,R)$ elements in terms of new degrees of freedom for Electromagnetic configuration, and construct the general expressions for conductivity with $SL(2,R)$ invariant. The holographic conductivities can be calculated using horizon data in an external magnetic field, and we show the numerical results using the linear response theory.

hep-th↗

arXiv2017

RG flow of entanglement entropy to thermal entropy

Utilizing the holographic technique, we investigate how the entanglement entropy evolves along the RG flow. After introducing a new generalized temperature which satisfies the thermodynamics-like law even in the IR regime, we find that the renormalized entropy and the generalized temperature in the IR limit approach the thermal entropy and thermodynamic temperature of a real thermal system. This result implies that the microscopic quantum entanglement entropy in the IR region leads to the thermodynamic relation up to small quantum corrections caused by the quantum entanglement near the entangling surface. Intriguingly, this IR feature of the entanglement entropy universally happens regardless of the detail of the dual field theory and the shape of the entangling surface. We check this IR universality with a most general geometry called the hyperscaling violation geometry which is dual to a relativistic non-conformal field theory.

hep-th↗

arXiv2016

Meson's Correlation Functions in a Nuclear Medium

We investigate meson's spectrum, decay constant and form factor in a nuclear medium through holographic two- and three-point correlation functions. To describe a nuclear medium composed of protons and neutrons, we consider a hard wall model on the thermal charged AdS geometry and show that due to the isospin interaction with a nuclear medium, there exist splittings of the meson's spectrum, decay constant and form factor relying on the isospin charge. In addition, we show that the $ρ$-meson's form factor describing an interaction with pseudoscalar fluctuation decreases when the nuclear density increases, while the interaction with a longitudinal part of an axial vector meson increases.

hep-th↗

arXiv2016

On black hole thermodynamics with a momentum relaxation

We investigate black hole thermodynamics involving a scalar hair which is dual to a momentum relaxation of the dual field theory. This black hole geometry is able to be classified by two parameters. One is a momentum relaxation and the other is a mass density of another matter localized at the center. Even though all parameters are continuous, there exists a specific point where its thermodynamic interpretation is not continuously connected to the one defined in the other parameter regime. The similar feature also appears in a topological AdS black hole. In this work, we show why such an unusual thermodynamic feature happens and provide a unified way to understand such an exotic black hole thermodynamically in the entire parameter range.

hep-th↗

arXiv2016

Emergent geometry from field theory: Wilson's renormalization group revisited

We find a geometrical description from a field theoretical setup based on Wilson's renormalization group in real space. We show that renormalization group equations of coupling parameters encode the metric structure of an emergent curved space, regarded to be an Einstein equation for the emergent gravity. Self-consistent equations of local order-parameter fields with an emergent metric turn out to describe low energy dynamics of a strongly coupled field theory, analogous to the Maxwell equation of the Einstein-Maxwell theory in the AdS$_{d+2}$/CFT$_{d+1}$ duality conjecture. We claim that the AdS$_{3}$/CFT$_{2}$ duality may be interpreted as Landau-Ginzburg theory combined with Wilson's renormalization group, which introduces vertex corrections into the Landau-Ginzburg theory in the large$-N_{s}$ limit, where $N_{s}$ is the number of fermion flavors.

hep-th↗

arXiv2016

Thermodynamic law from the entanglement entropy bound

From black hole thermodynamics, the Bekenstein bound has been proposed as a universal thermal entropy bound. It has been further generalized to an entanglement entropy bound which is valid even in a quantum system. In a quantumly entangled system, the non-negativity of the relative entropy leads to the entanglement entropy bound. When the entanglement entropy bound is saturated, a quantum system satisfies the thermodynamics-like law with an appropriately defined entanglement temperature. We show that the saturation of the entanglement entropy bound accounts for a universal feature of the entanglement temperature proportional to the inverse of the system size. In addition, we show that the deformed modular Hamiltonian under a global quench also satisfies the generalized entanglement entropy boundary after introducing a new quantity called the entanglement chemical potential.

hep-th↗

arXiv2016

Conductivities in an anisotropic medium

In order to imitate anisotropic medium of a condensed matter system, we take into account an Einstein-Maxwell-dilaton-axion model as a dual gravity theory where the anisotropy is caused by different momentum relaxations. This gravity model allows an anisotropic charged black hole solution. On this background, we investigate how the linear responses of vector modes like electric, thermoelectric, and thermal conductivities rely on the anisotropy. We find that the electric conductivity in low frequency limit shows a Drude peak and that in the intermediate frequency regime it reveals the power law behavior. Especially, when the anisotropy increases the exponent of the power law becomes smaller. In addition, we find that there exist a critical value for the anisotropy at which the DC conductivity reaches to its maximum value.

hep-th↗

arXiv2015

Logarithmic Corrections to the Entanglement Entropy

In a $d$-dimensional conformal field theory, it has been known that a relevant deformation operator with the conformal dimension, $Δ=\frac{d+2}{2}$, generates a logarithmic correction to the entanglement entropy. In the large 't Hooft coupling limit, we can investigate such a logarithmic correction holographically by deforming an AdS space with a massive scalar field dual to the operator with $Δ=\frac{d+2}{2}$. There are two sources generating the logarithmic correction. One is the metric deformation and the other is the minimal surface deformation. In this work, we investigate the change of the entanglement entropy caused by the minimal surface deformation and find that the second order minimal surface deformation leads to an additional logarithmic correction.

hep-th↗

arXiv2015

Holographic Entanglement Entropy of Mass-deformed ABJM Theory

We investigate the effect of supersymmetry preserving mass deformation near the UV fixed point represented by the ${\cal N}=6$ ABJM theory. In the context of the gauge/gravity duality, we analytically calculate the leading small mass effect on the renormalized entanglement entropy (REE) for the most general Lin-Lunin-Maldacena (LLM) geometries in the cases of the strip and disk shaped entangling surfaces. Our result shows that the properties of the REE in (2+1)-dimensions are consistent with those of the $c$-function in (1+1)-dimensions. We also discuss the validity of our computations in terms of the curvature behavior of the LLM geometry in the large $N$ limit and the relation between the correlation length and the mass parameter for a special LLM solution.

hep-th↗

arXiv2015

Holographic Nucleons in the Nuclear Medium

We investigate the nucleon's rest mass and dispersion relation in the nuclear medium which is holographically described by the thermal charged AdS geometry. On this background, the chiral condensate plays an important role to determine the nucleon's mass in both the vacuum and the nuclear medium. It also significantly modifies the nucleon's dispersion relation. The nucleon's mass in the high density regime increases with density as expected, while in the low density regime it slightly decreases. We further study the splitting of the nucleon's masses caused by the isospin interaction with the nuclear medium.

hep-th↗

arXiv2015

Holographic entanglement entropy in the nonconformal medium

We investigate holographically the entanglement entropy of a nonconformal medium whose dual geometry is described by an Einstein-Maxwell-dilaton theory. Due to an additional conserved charge corresponding to the number operator, its thermodynamics can be represented in a grandcanonical or canonical ensemble. We study thermodynamics in both ensembles by using the holographic renormalization and the entanglement entropy of a nonconformal medium. After defining the entanglement chemical potential which unlike the entanglement temperature has a nontrivial size dependence, we find that the entanglement entropy of a small subsystem satisfies the relation resembling the first law of thermodynamics in a medium. Furthermore, we study the entanglement entropy change in the nonconformal medium caused by the excitation of the ground state and by the global quench corresponding to the insertion of particles.

hep-th↗

arXiv2014

Properties of Holographic Mesons on Dense Medium

We study the energy dispersions of holographic light mesons and their decay constants on dense nuclear medium. As the spatial momenta of mesons along the boundary direction increase, both observables of the mesons not only increase but also split according to the isospin charges. The decay constant of the negative meson is more large than that of the positive meson of the same type due to the chemical potentials of the background nucleons.

hep-ph↗

arXiv2014

Soft Wall Model in the Hadronic Medium

We study the holographic QCD in the hadronic medium by using the soft wall model. We discuss the Hawking-Page transition between Reissner-Nordström AdS black hole and thermal charged AdS of which the geometries correspond to deconfinement and confinement phases respectively. We also present the numerical result of the vector and axial vector meson spectra depending on the quark density.

hep-th↗

arXiv2014

Nucleon mass splitting in the isospin medium

Using the AdS/CFT correspondence, we investigate a nucleon mass splitting and nucleon-pion coupling in the isospin medium. We find that there exists a nucleon mass splitting which is exactly given by the half of the meson mass splitting because nucleon has the half isospin charge of the charged mesons. In addition, we also investigate the nucleon-pion coupling, which requires the modification of the known Abelian-type unitary gauge fixing term because non-Abelian fluctuations should be taken into account in the isospin medium. In this paper, after constructing an appropriate unitary gauge fixing term, we find that in spite of the nucleon's and meson's mass splittings, there is no nucleon-pion coupling splitting in the isospin medium.

hep-th↗

arXiv2014

Holographic renormalization in dense medium

We investigate the holographic renormalization of a charged black brane with or without a dilaton field, whose dual field theory describes a dense medium at finite temperature. In a dense medium, two different thermodynamic descriptions are possible due to an additional conserved charge. These two different thermodynamic ensembles are classified by the asymptotic boundary condition of the bulk gauge field. We show that in the holographic renormalization regularity of all bulk fields can reproduce consistent thermodynamic quantities and that the Bekenstein-Hawking entropy is nothing but the renormalized thermal entropy of the dual field theory. Furthermore, we find that the Reissner-Nordstrom AdS black brane is dual to a theory with conformal matter as expected, whereas a charged black brane with a nontrivial dilaton profile is mapped to a theory with non-conformal matter although its leading asymptotic geometry still remains as AdS space.

hep-th↗

arXiv2014

Renormalized Entanglement Entropy Flow in Mass-deformed ABJM Theory

We investigate a mass deformation effect on the renormalized entanglement entropy (REE) near the UV fixed point in (2+1)-dimensional field theory. In the context of the gauge/gravity duality, we use the Lin-Lunin-Maldacena (LLM) geometries corresponding to the vacua of the mass-deformed ABJM theory. We analytically compute the small mass effect for various droplet configurations and show in holographic point of view that the REE is monotonically decreasing, positive, and stationary at the UV fixed point. These properties of the REE in (2+1)-dimensions are consistent with the Zamolodchikov $c$-function proposed in (1+1)-dimensional conformal field theory.

hep-th↗

arXiv2013

A Massive Quasi-normal Mode in the Holographic Lifshitz Theory

We investigate the holographic renormalization of the Einstein-Maxwell-dilaton theory which provides an asymptotic Lifshitz geometry dual to a Lifshitz field theory. In this case, the existence of a field combination with zero scaling dimension causes an ambiguity in fixing local counter terms. Nevertheless, we show that all possible local counter terms give rise to consistent thermodynamic quantities with the Lifshitz black brane results. In addition, we also study the retarded Green functions of the current and momentum operator of a non-relativistic Lifshitz field theory. In the non-zero momentum regime, the results show intriguingly that there exists a massive quasi-normal mode whose effective mass is linearly proportional to temperature and that even at zero temperature there exists a quasi-normal mode in the non-relativistic Lifshitz medium.

hep-th↗

arXiv2013

Notes on the holographic Lifshitz theory

On the Lifshitz black brane geometry of an Einstein-Maxwell-dilaton gravity, we holographically investigate electric DC conductivities and the role of impurity in a non-relativistic Lifshitz medium with two different charge carriers, impurity and Lifshitz matter. The conductivity carried by Lifshitz matter is proportional to the square of temperature, while that carried by impurity crucially depends on the bulk coupling parameter \g. For \g < -2, impurity at high temperature can change the electric property of the Lifshitz medium significantly so that the Lifshitz matter with impurity can show a totally different electric property from the pure Lifshitz matter.

hep-th↗