Myungseok Eune

Hawking-Page phase transition in BTZ black hole revisited

A bstractWe consider the Hawking-Page phase transition between the BTZ black hole of M ≥ 0 and the thermal soliton of M = −1. In this system, there exists a mass gap so that there does not seem to exist a continuous thermodynamic phase transition. We consistently construct the off-shell free energies of the black hole and the soliton by properly taking into account the conical space. And then, the continuous off-shell free energy to describe tunneling effect can be realized through non-equilibrium solitons.We derive the BPS type of first order differential equations for the rotating black hole solutions in the three-dimensional Einstein gravity coupled minimally with a self-interacting scalar field, using fake supersymmetry formalism. It turns out that the formalism is not complete and should be augmented by an additional equation to imply the full equations of motion. We identify this additional equation as a constraint by using an effective action method. By computing the renormalized boundary stress tensor, we obtain the mass and angular momentum of the black hole solutions of these first order equations and confirm that they saturate the BPS bound.

SURFACE GRAVITY AND HAWKING TEMPERATURE FROM ENTROPIC FORCE VIEWPOINT

We consider a freely falling holographic screen for the Schwarzschild and Reissner–Nordstrom black holes and evaluate the entropic force a la Verlinde. When the screen crosses the event horizon, the temperature of the screen agrees to the Hawking temperature and the entropic force gives rise to the surface gravity for both of the black holes.

Emergent Friedmann equation from the evolution of cosmic space revisited

Following the recent study on the emergent Friedmann equation from the expansion of cosmic space for a flat universe, we apply this method to a nonflat universe, and modify the evolution equation to lead to the Friedmann equation. In order to maintain the same form with the original evolution equation, we have to define the time-dependent Planck length, which shows that the spatial curvature of k = 0 and k = 1 is preferable to k = 1 since the Planck length of the nonflat open universe is divergent. Finally, we discuss its physical consequences.

Something special at the event horizon

We revisit the free-fall energy density of scalar fields semiclassically by employing the trace anomaly on a two-dimensional Schwarzschild black hole with respect to various black hole states in order to clarify whether something special at the horizon happens or not. For the Boulware state, the energy density at the horizon is always negative divergent, which is independent of initial free-fall positions. However, in the Unruh state the initial free-fall position is responsible for the energy density at the horizon and there is a critical point to determine the sign of the energy density at the horizon. In particular, a huge negative energy density appears when the freely falling observer is dropped just near the horizon. For the Hartle–Hawking state, it may also be positive or negative depending on the initial free-fall position, but it is always finite. Finally, we discuss physical consequences of these calculations.

Effective potentials in the Lifshitz scalar field theory

Abstract We study the one-loop effective potentials of the four-dimensional Lifshitz scalar field theory with the particular anisotropic scaling z = 2 , and the mass and the coupling constants renormalization are performed whereas the finite counterterm is just needed for the highest order of the coupling because of the mild UV divergence. Finally, we investigate whether the critical temperature for the symmetry breaking can exist or not in this approximation.

Note on an action for a particle in the Ho\v{r}ava-Lifshitz Gravity

We classify a recently proposed action for a free particle which is compatible with Hořava–Lifshitz gravity, and then obtain the subluminal and the superluminal limits without gauge ambiguity in terms of Hamiltonian formulation.

Lifshitz scalar, brick wall method, and GUP in Horava-Lifshitz Gravity

Abstract Using the brick wall method, we study statistical entropy for spherically symmetric black holes in Hořava-Lifshitz gravity. In particular, a Lifshitz scalar field is considered in order to incorporate foliation preserving diffeomorphism which eventually gives a modified dispersion relation. Finally, we obtain the area law without UV cutoff for z > 3, and discuss some of consequences in connection with the generalized uncertainty principle.

Entropy and temperatures of Nariai black hole

Abstract The statistical entropy of the Nariai black hole in a thermal equilibrium is calculated by using the brick-wall method. Even if the temperature depends on the choice of the timelike Killing vector, the entropy can be written by the ordinary area law which agrees with the Wald entropy. We discuss some physical consequences of this result and the properties of the temperatures.

Local thermodynamics of KS black hole

We study the thermodynamics of the KS black hole which is an asymptotically flat solution of the HL gravity. In particular, we introduce a cavity to describe the thermodynamics at a finite isothermal surface on general ground and to get a well-defined thermodynamics. We show that there exists a locally stable small black hole which tunnels to the hot flat space below the critical temperature and to the large black hole above the critical temperature. Moreover, it turns out that the remnant decays into the vacuum through a quantum tunneling.

Nonextremal Kerr/CFT on a stretched horizon

A bstractWe study the conformal symmetry described by SL(2, R)L × SL(2, R)R in the nonextremal Kerr black hole case. We calculate the central charges cL,R separately on a stretched horizon by the Hamiltonian gravity. In order to get two sets of conformal symmetry, we consider two Killing vectors each of which depends on either one of the two independent coordinates separated in the spirit of point-splitting from the angular coordinate of the corotating frame at the horizon. Then, we obtain the Bekenstein-Hawking entropy by the Cardy formula.