Chanyong Park

Spiky strings on AdS4 × CP3

We study a giant magnon and a spike solution for the string rotating on AdS(4) X CP**3 geometry. We consider rigid rotating fundamental string in the SU(2) X SU(2) sector inside the CP**3 and find out the general form of all the conserved charges. We find out the dispersion relation corresponding to both the known giant magnon and the new spike solutions. We further study the finite size correction in both cases.

A dual geometry of the hadron in dense matter

We identify the dual geometry of the hadron phase of dense nuclear matter and investigate the confinement/deconfinement phase transition. We suggest that the low temperature phase of the RN black hole with the full backreaction of the bulk gauge field is described by the zero mass limit of the RN black hole with hard wall. We calculated the density dependence of critical temperature and found that the phase diagram closes. We also study the density dependence of the ρ meson mass.

Correlation functions of magnon and spike

After considering a solitonic string moving in the Poincare

On the giant magnon and spike solutions for strings on AdS3 × S3

AdS

Strange metallic behavior in anisotropic background

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.

Deconfinement phase transition in holographic QCD with matter

We study solutions for the rotating strings on the sphere with a background NS-NS field and on the anti-de-Sitter spacetime. We show the existence of magnon and single spike solutions on R × S2 in the presence of constant magnetic field as two limiting cases. We also study the solution for strings on AdS3 × S3 with Melvin deformation. The dispersion relations among various conserved charges are shown to receive finite corrections due to the deformation parameter. We further study the rotating string on AdS3 × S3 geometry with two conserved angular momenta on S3 and one spin along the AdS3. We show that there exists two kinds of solutions: a circular string solution and a helical string. We find out the dispersion relation among various charges and give physical interpretation of these solutions.

Dissociation of a heavy meson in the quark medium

We continue our analysis on conductivity in the anisotropic background by employing the D-brane probe technique, where the D-branes play the role of charge carriers. The DC and AC conductivity for massless charge carriers are obtained analytically, while interesting curves for the AC conductivity are also plotted. For massive charge carriers, we calculate the DC and AC conductivities in the dilute limit and we fix the parameters in the Einstein-Maxwell-dilaton theory so that the background exhibits the same scaling behaviors as those for real-world strange metals. The DC conductivity at finite density is also computed.

Holographic QCD in medium: A Bottom up approach

In the framework of a holographic QCD approach we study the influence of matter on the deconfinement temperature T{sub c}. We first consider the quark flavor number (N{sub f}) dependence of T{sub c}. We observe that T{sub c} decreases with N{sub f}, which is consistent with a lattice QCD result. We also delve into how the quark number density {rho}{sub q} affects the value of T{sub c}. We find that T{sub c} drops with increasing {rho}{sub q}. In both cases, we confirm that the contributions from quarks are suppressed by 1/N{sub c}, as it should be, compared to the ones from a gravitational action (pure Yang-Mills theory)

Correlation function of dyonic strings

We investigate the dissociation of a heavy meson in the medium composed of light quarks and gluons. In the quark-gluon plasma, the dissociation length of the heavy meson becomes short as the temperature or quark chemical potential increases. On the contrary, in the hadronic phase the dissociation length becomes large as the chemical potential increases, due to the different dissociation mechanism with one used in the quark-gluon plasma.

Conductivity in the anisotropic background

A holographic dual of hadrons at finite density is considered. We use the zero black-hole mass limit of Reisner-Nordstrom (RN) AdS background with hard wall to describe a confining background with finite quark density. We calculate density-dependence of meson masses and decay constants. In our model, pion decay constant and its velocity go down but all the meson masses go up as density grows. We also shows that there is a phase transition at 3 times of normal nuclear density, where deconfinement and chiral restoration transition happen simultaneously.