The entropy of Garfinkle-Horne dilaton black hole due to arbitrary spin fields

Using the membrane model which is based on brick wall model, we calculated the free energy and entropy of Garfinkle-Horne dilatonic black hole due to arbitrary spin fields. The result shows that the entropy of scalar field and the entropy of Fermionic field have similar formulas. There is only a coefficient between them.     

Are Axidilaton Stars Massive Compact Halo Objects?

Boson stars built from a very light Kalb–Ramond axion, the dilaton or other moduli fields of effective string models could provide a considerable fraction of the non-baryonic part of dark matter. Gravitational microlensing of 0.5 M MACHOs within the halo of galaxies may indirectly "weighing" the mass of the constituent scalar particle, resulting in 10^–10 eV/c².     

Thermodynamic quantities around a charged dilaton black hole

We use the brick-wall method to investigate the thermodynamic quantities around a charged dilaton black hole. We show that all the thermodynamic quantities contain two terms: the first term has exactly the same form as in a flat space-time, but the second term depends explicitly on the spin of the fields and therefore cannot be neglected. __________ Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 157, No. 1, pp. 154–160, October, 2008.     

在具有伸缩子的QCD势模型中的重介子

从伸缩子–胶子有效耦合理论得到的重夸克–反夸克势模型出发,计算了重介子的自旋平均能谱及轻子衰变和辐射跃迁宽度,并与Cornell势模型所得到的相应结果作了比较.结果表明,新的重夸克势的计算结果与重介子的实验数据更好地符合,而且估计的伸缩子质量5?7MeV很好地位于有关伸缩子质量的其他理论途径所估计的范围之内.     

Dilatonic Dark Energy Model with Late Time de Sitter Attractor

Based on Weyl-scaled induced gravitational theory, we regard dilaton field in this theory as a candidate of dark energy. We construct a dilatonic dark energy model and its phantom model, that admit late time de Sitter attractor solution. When we take the potential of dilaton field as the form which has been studied in supergravity model and the famous Mexican hat potential , we show mathematically that these attractor solutions correspond to an equation of state ω = −1 and a cosmic density parameter Ω_σ = 1, which are important features for a dark energy model that can meet the current observations.     

Dilaton Black Hole Tunneling Radiation in de Sitter Universe

The Hawking radiation via tunneling from the dilaton black hole in de Sitter universe is investigated using Parikh Wilczek＇s method. We show that if the self-gravitational interaction and energy conservation are taken into account, the modified radiation spectrum deviates from exact thermal spectrum and satisfies the unitary theory.     

Gravitational scattering of massless scalars in QFT and superstring theory

In this paper we perform the calculation of the gravitational scattering amplitude for 4 massless scalars in quantum field theory and Type II superstring theory. We show that the results agree, providing an example of how gravity is incorporated in the superstring theory. During the calculation we quantize gravitational action to derive graviton propagator and interaction vertex with massless scalar. We also calculate general 3‐point and 4‐point scattering amplitudes in SST for open and closed massless strings in NS sector.     

Spectroscopy of rotating linear dilaton black holes from boxed quasinormal modes

Numerical studies of the coupled Einstein‐Klein‐Gordon system have recently revealed that confined scalar fields generically collapse to form caged black holes. In the light of this finding, we analytically study the characteristic resonance spectra of the confined scalar fields in rotating linear dilaton black hole geometry. Confining mirrors (cage) are assumed to be placed in the near‐horizon region of a caged rotating linear dilaton black hole ( is the radius of the cage and r₂ represents the event horizon). The radial part of the Klein‐Gordon equation is written as a Schrödinger‐like wave equation, which reduces to a Bessel differential equation around the event horizon. Using analytical tools and proper boundary conditions, we obtain the boxed‐quasinormal mode frequencies of the caged rotating linear dilaton black hole. Finally, we employ Maggiore's method, which evaluates the transition frequency in the adiabatic invariant quantity from the highly damped quasinormal modes, in order to investigate the entropy/area spectra of the rotating linear dilaton black hole.     

Quasinormal Modes of Charged Dilaton Black Holes in 2 + 1 Dimensions

We have studied the scalar perturbation of static charged dilaton black holes in 2 + 1 dimensions. The black hole considered here is a solution to the low-energy string theory in 2 + 1 dimensions. It is asymptotic to the anti-de Sitter space. The exact values of quasinormal modes for the scalar perturbations are calculated. For both the charged and uncharged cases, the quasinormal frequencies are pure-imaginary leading to purely damped modes for the perturbations.