A5079949988- Black Holes and Theoretical Physics
- Cosmology and Gravitation Theories
- Pulsars and Gravitational Waves Research
- Advanced Differential Geometry Research
- Nuclear physics research studies
- Astrophysical Phenomena and Observations
- Nuclear Physics and Applications
- Noncommutative and Quantum Gravity Theories
- Quantum, superfluid, helium dynamics
- Nuclear reactor physics and engineering
- Relativity and Gravitational Theory
- Molecular Spectroscopy and Structure
Nagoya University
2021-2025
Abstract This study investigates the formation of primordial black holes (PBHs) resulting from extremely large amplitudes initial fluctuations in a radiation-dominated universe. We find that, for sufficiently amplitude, configuration trapping horizons shows characteristic structure due to existence bifurcating horizons. call this type B PBH, while without horizon A PBH. As shown ref. [1], matter-dominated universe, PBH can be realized by II fluctuation, which is characterized non-monotonic...
Abstract This study investigates the formation of primordial black holes (PBHs) resulting from collapse adiabatic fluctuations with large amplitudes and non-Gaussianity. Ref. [1] showed that lead to type B PBHs, characterized by existence bifurcating trapping horizons, distinct more common A PBHs without a horizon. We focus on local non-Gaussianity curvature perturbation ζ given function Gaussian random variable G as β ζ=-ln(1- ) parameter . Then we examine how influences dynamics PBH...
A bstract The Hawking-Moss (HM) bounce solution implies that the tunneling amplitude between vacua is uniquely determined by vacuum energy at initial and top of a potential barrier, regardless field distance them ∆ ϕ . This implausible conclusion was carefully discussed in [E. J. Weinberg, Phys. Rev. Lett. 98, 251303, (2007)], it concluded conventional HM not reliable for transition to distant local maxima (hereinafter referred as remote transition). We revisit this issue study impact...
Abstract We estimate the probability distribution for spins of primordial black holes (PBHs) that formed during an early matter-dominated era in Universe. employ Zel'dovich approximation and focus on linear-order effect cosmological perturbations which causes tidal torque. Assuming fluctuations obey Gaussian statistics, we apply peak theory random variables to compute root mean square (RMS) non-dimensional Kerr parameter a * at their formation. The value is evaluated through angular momentum...
We study false vacuum decay in a black hole (BH) spacetime with an angular momentum. Considering the region described by Kerr--de Sitter geometry, under thin wall approximation, we can obtain stationary configuration of bubble seen from outside without specifying geometry inside domain wall. Then, assuming true is Kerr fix mass and spin parameter for imposing first junction conditions conservation Although assumption cannot be fully consistent second conditions, roughly evaluate error...
We analyse vacuum decay in rotating BTZ black hole spacetimes with the thin wall approximation. Possible parameter regions for are clarified. find that nucleation rate is dominated by bounce solution static shell configuration. The of decreases mass initial hole. For a larger/smaller value hole, can be smaller/larger than Coleman De Luccia pure AdS spacetime. Through decay, gains its and loses horizon area. also increases increasing angular momentum