9466118
Quantum formation of black holes and wormholes in the gravitational collapse of a dust shell.
Quantum-mechanical model of self-gravitating dust shell is considered. To clarify the relation between classical and quantum spacetime which the shell collapse form, we consider various time slicing on which quantum mechanics is developed. By considering the static time slicing which corresponds to an observer at a constant circumference radius, we obtain the wave functions of the shell motion and the discrete mass spectra which specify the global structures of spherically symmetric spacetime formed by the shell collapse. It is found that wormhole states are forbidden when the rest mass is comparable with Plank mass scale due to the zero-point quantum fluctuations.
119135270
Construction of gauge-invariant variables of linear metric perturbations on an arbitrary background spacetime
An outline of a proof of the decomposition of linear metric perturbations into gauge-invariant and gauge-variant parts on the an arbitrary background spacetime which admits ADM decomposition is discussed. We explicitly construct the gauge-invariant and gauge-variant parts of the linear metric perturbations through the assumption of the existence of some Green functions. We also confirm the result through another approach. This implies that we can develop the higher-order gauge-invariant perturbation theory on an arbitrary background spacetime. Remaining issues to complete the general-framework of the general-relativistic higher-order gauge-invariant perturbation theories are also discussed.
14230146
Consistency of Equations in the Second-Order Gauge- Invariant Cosmological Perturbation Theory
Along the general framework of the gauge-invariant perturbation theory developed in the papers [K. Nakamura, Prog. Theor. Phys. 110 (2003), 723; Prog. Theor. Phys. 113 (2005), 481], we rederive the second-order Einstein equation on four-dimensional homogeneous isotropic background universe in a gauge-invariant manner without ignoring any mode of perturbations. We consider the perturbations both in the universe dominated by the single perfect fluid and in that dominated by the single scalar field. We also confirmed the consistency of all the equations of the second-order Einstein equation and the equations of motion for matter fields, which are derived in the paper [K. Nakamura, arXiv:0804.3840]. This confirmation implies that all the derived equations of the second order are self-consistent and these equations are correct in this sense. Subject Index: 450, 451
56300409
Second-order Gauge-Invariant Cosmological Perturbation Theory: Current Status
The current status of the recent developments of the second-order gauge-invariant cosmological perturbation theory is reviewed. To show the essence of this perturbation theory, we concentrate only on the universe filled with a single scalar field. Through this paper, we point out the problems which should be clarified for the further theoretical sophistication of this perturbation theory. We also expect that this theoretical sophistication will be also useful to discuss the theoretical predictions 
of non-Gaussianity in CMB and comparison with observations.
17008663
Inclusion of the first-order vector- and tensor-modes in the second-order gauge-invariant cosmological perturbation theory
Gauge-invariant treatments of the second-order cosmological perturbation in a four dimensional homogeneous isotropic universe are formulated without any gauge fixing. We have derived the Einstein equations in the case of the single perfect fluid without ignoring any modes. These equations imply that any types of mode-coupling arise due to the second-order effects of the Einstein equations.
121942149
Supernova nucleosynthesis and neutrino oscillation
Neutrinos play the critical roles in nucleosynthesis of light-to-heavy mass nuclei like 7Li, 11B, 138La and 180Ta in core-collapse supernovae. We find average neutrino temperatures of three flavor neutrinos so that the supernova nucleosynthesis models of the neutrino-process and the r-process can explain the observed solar-system abundance and Galactic chemical evolution of these isotopes. We propose a method to determine the unknown neutrino oscillation parameters θ13 and mass hierarchy by the use of the MSW effects on the supernova nucleosynthesis.
19435400
Almost analytic solutions to equilibrium sequences of irrotational binary polytropic stars for n = 1
A solution to an equilibrium of irrotational binary polytropic stars in Newtonian gravity is expanded in a power of epsilon = a(0)/R, where R and a(0) are the separation of the binary system and the radius of each star for R = infinity. For the polytropic index n = 1, the solutions are given almost analytically up to order epsilon(6). We have found that in general an equilibrium solution should have the velocity component along the orbital axis and that the central density should decrease when R decreases. Our almost analytic solutions can be used to check the validity of numerical solutions.