Asymmetry in Microlensing-Induced Light Curves

We discuss distortion in microlensing-induced light curves which are considered to be curves due to single-point-mass lenses at a first glance. As factors of the distortion, we consider close binary and planetary systems, which are the limiting cases of two-point-mass lenses, and the gravitational potential is regarded as the sum of the single point mass and the corrections. In order to quantitatively estimate the asymmetric features of such distorted light curves, we propose a cutoff dependent skewness, and show how to discriminate the similar light curves with it. We also examine as the distortion the general relativistic effect of frame dragging, but the effect coincides with the close binary case in the light curves.Comment: 18 pages, 17 eps figures, Accepted for publication in Prog. Theor. Phy

Rotating black hole in extended Chern-Simons modified gravity

We investigate a slowly rotating black hole in four-dimensional extended Chern-Simons modified gravity. We obtain an approximate solution that reduces to the Kerr solution when a coupling constant vanishes. The Chern-Simons correction effectively reduces the frame-dragging effect around a black hole in comparison with that of the Kerr solution.Comment: 9 pages, 1 figure, to appear in Progress of Theoretical Physics, typos correcte

Does a black hole rotate in Chern-Simons modified gravity?

Rotating black hole solutions in the (3+1)-dimensional Chern-Simons modified gravity theory are discussed by taking account of perturbation around the Schwarzschild solution. The zenith-angle dependence of a metric function related to the frame-dragging effect is determined from a constraint equation independently of a choice of the embedding coordinate. We find that at least within the framework of the first-order perturbation method, the black hole cannot rotate for finite black hole mass if the embedding coordinate is taken to be a timelike vector. However, the rotation can be permitted in the limit of $M/r \to 0$ (where $M$ is the black hole mass and $r$ is the radius). For a spacelike vector, the rotation can also be permitted for any value of the black hole mass.Comment: 4 pages, Accepted for publication in Phys. Rev.

Flat rotation curves in Chern-Simons modified gravity

We investigate the spacetime of a slowly rotating black hole in the Chern-Simons modified gravity. The long range feature of frame-dragging effect under the Chern-Simon gravity well explains the flat rotation curves of galaxies which is a central evidence of dark matter. Our solution provides a different scenario of rotating space from Goedel's solution.Comment: 4 pages, Accepted for publication in Phys. Rev.

The effect of dissipation on quantum transmission resonance

Quantum transmissions of a free particle passing through a rectangular potential barrier with dissipation are studied using a path decomposition technique. Dissipative processes strongly suppress the transmission probability at resonance just above the barrier resulting in an unexpected reduction of the mean traversal time through the potential barrier.Comment: 8 pages, 5 figures, Accepted for publication in Physics Letters