H. W. Lee

Role of the Brans–Dicke scalar in the holographic description of dark energy

Abstract We study cosmological application of the holographic energy density in the Brans–Dicke theory. Considering the holographic energy density as a dynamical cosmological constant, it is more natural to study it in the Brans–Dicke theory than in general relativity. Solving the Friedmann and Brans–Dicke field equations numerically, we clarify the role of Brans–Dicke field during evolution of the universe. When the Hubble horizon is taken as the IR cutoff, the equation of state ( w Λ ) for the holographic energy density is determined to be 5 3 when the Brans–Dicke parameter ω goes infinity. This means that the Brans–Dicke field plays a crucial role in determining the equation of state. For the particle horizon IR cutoff, the Brans–Dicke scalar mediates a transition from w Λ = − 1 / 3 (past) to w Λ = 1 / 3 (future). If a dust matter is present, it determines future equation of state. In the case of future event horizon cutoff, the role of the Brans–Dicke scalar and dust matter are turned out to be trivial, whereas the holographic energy density plays an important role as a dark energy candidate with w Λ = − 1 .

Role of the brane curvature scalar in the brane world cosmology

Abstract We include the brane curvature scalar to study its cosmological implication in the brane world cosmology. This term is usually introduced to obtain the well-defined stress-energy tensor on the boundary of anti-de-Sitter–Schwarzschild space. Here we treat this as the perturbed term for cosmological purpose. We find corrections to the well-known equation of the brane cosmology. It contains new interesting terms which may play the important role in the brane cosmology.

Holographic principle in the Binetruy-Deffayet-Langlois brane cosmology

We study the holographic principle in the brane cosmology. Especially we describe how to accommodate the 5D anti de Sitter Schwarzschild (AdSS5) black hole in the Binetruy-Deffayet-Langlois (BDL) approach of brane cosmology. It is easy to make a connection between a mass M of the AdSS5 black hole and a conformal field theory (CFT)-radiation dominated universe on the brane in the moving domain wall approach. But this is not established in the BDL approach. In this case we use two parameters C1, C2 in the Friedmann equation. These arise from integration and are really related to the choice of initial bulk matter. If one chooses a bulk energy density ρB to account for a mass M of the AdSS5 black hole and the static fifth dimension, a CFTradiation term with ρCFT ∼ M/a 4 comes out from the bulk matter without introducing a localized matter distribution on the brane. This means that the holographic principle can be established in the BDL brane cosmology. E-mail address: dtpnjk@ijnc.inje.ac.kr E-mail address: hwlee@physics.inje.ac.kr E-mail address: ysmyung@physics.inje.ac.kr gwkang@post.kek.jp

Randall–Sundrum choice in the brane world

Abstract We discuss the Randall–Sundrum (RS) choice for hMN in the brane world. We begin with the de Donder gauge (transverse-tracefree) including scalar(h55), vector(h5μ) and tensor(hμν) in five dimensions for comparison. One finds that h55=0 and h5μ=0. This leads to the RS choice. It appears that the RS choice is so restrictive for the five massless states, whereas it is unique for describing the massive states. Furthermore, one can establish the stability of the RS solution with the RS choice only.

Schwarzschild black hole in the dilatonic domain wall

In the dilatonic domain wall model, we study the Schwarzschild black hole as a solution to the Kaluza-Klein zero mode effective action which is equivalent to the Brans-Dicke (BD) model with a potential. This can describe the large Randall-Sundrum (RS) black hole whose horizon is to be the intersection of the black cigar with the brane. The black cigar located far from the five-dimensional antichar21{}de Sitter

Greybody factor for D3-branes in aBfield

({mathrm{AdS}}_{5})

S -wave absorption of scalars by noncommutative D3-branes

horizon is known to be stable, but any explicit calculation for stability of the RS black hole at

ANALYSIS OF GRAVITATIONAL WAVE EXPERIMENTAL DATA WITH DISTRIBUTED COMPUTING

z=0

Dynamical behavior of dilaton in de Sitter space

has not yet been performed. Here its stability is investigated against the z-independent perturbations composed of odd-even parities of graviton

Holographic energy density in the Brans-Dicke theory

{(h}_{ensuremath{mu}ensuremath{nu}})