A5088682748- Black Holes and Theoretical Physics
- Cosmology and Gravitation Theories
- Pulsars and Gravitational Waves Research
- Quantum Electrodynamics and Casimir Effect
- Astrophysical Phenomena and Observations
- Noncommutative and Quantum Gravity Theories
- Quantum Mechanics and Applications
- Advanced Differential Geometry Research
- Geophysics and Sensor Technology
- Geophysics and Gravity Measurements
- Relativity and Gravitational Theory
- Galaxies: Formation, Evolution, Phenomena
- Advanced Thermodynamics and Statistical Mechanics
- Particle Accelerators and Free-Electron Lasers
- Laser-Plasma Interactions and Diagnostics
- Particle physics theoretical and experimental studies
- Gamma-ray bursts and supernovae
- Nuclear physics research studies
- Advanced Numerical Methods in Computational Mathematics
- Tribology and Lubrication Engineering
- Mechanical and Optical Resonators
- Numerical methods for differential equations
- Nonlinear Waves and Solitons
- Laser Design and Applications
- Experimental and Theoretical Physics Studies
RIKEN
2021-2024
Nippon Soken (Japan)
2021-2024
Kyoto University
2022-2024
Instituto de Física Teórica
2024
Yukawa Institute for Theoretical Physics
2024
Perimeter Institute
2020-2021
The University of Tokyo
2015-2020
Hiroshima University
2014
It is shown that the spectral amplitude of gravitational wave ringdown a Kerr black hole sourced by an extreme mass ratio merger can be modeled greybody factor, which quantifies scattering nature geometry. The estimation and spin remnant demonstrated fitting factor to data without using quasinormal modes. We propose modeling with may strengthen test gravity as one avoid possible overfitting issue start time problem in superposed
One of the most triumphant predictions theory if general relativity was recent LIGO-Virgo detection gravitational wave (GW) signals produced in binary black hole (BH) mergers. However, it is suggested that exotic compact objects, proposed quantum gravity models BHs, may produce similar classical GW waveforms, followed by delayed repeating "echoes". In a companion paper [1], we have presented different arguments for universal Boltzmann reflectivity BH horizons. Here, investigate resulting...
We find a significant destructive interference among Kerr overtones in the early ringdown induced by an extreme mass-ratio merger of massive black hole and compact object, that spectrum apparently follows Fermi-Dirac distribution. numerically compute spectral amplitude gravitational waves particle plunging into study excitation multiple quasi-normal (QN) modes. start time is before strain peak signal corresponds to when passes photon sphere. When has near-extremal rotation, QN frequencies...
Quantum nature of black hole horizons has been a subject recent interest and scrutiny. In particular, near-horizon quantum violation the equivalence principle proposed as resolution information paradox. Such may lead to modified dispersion relation at high energies, which could become relevant due intense gravitational blueshift experienced by ingoing waves. We investigate ringdown for perturbed with such find that infalling waves are partially reflected near horizon. This results in...
We study the reflectivity of quantum black hole (BH) horizons using detailed balance and fluctuation-dissipation theorem, finding a universal flux given by Boltzmann factor = exp (−(ℏ ||)/(k TH)), where ̃ω is frequency in horizon frame TH Hawking temperature. This implies CP-symmetry (or 3 topology) extended BH spacetime. then briefly discuss related physical implications: we predict echoes ringdown Kerr BHs, but they do not exhibit ergoregion instability. The viscosity membrane paradigm...
Black Holes are possibly the most enigmatic objects in our universe. From their detection gravitational waves upon mergers, to snapshot eating at centres of galaxies, black hole astrophysics has undergone an observational renaissance past four years. Nevertheless, they remain active playgrounds for strong gravity and quantum effects, where novel aspects elusive theory may be hard work. In this review article, we provide overview motivations why “Quantum Holes” radically different from...
Abstract We study static tidal Love numbers (TLNs) of a and spherically symmetric black hole for odd-parity metric perturbations. describe perturbations using the effective field theory (EFT), formulated on an arbitrary background with timelike scalar profile in context scalar-tensor theories. In particular, we obtain solution generalized Regge-Wheeler equation order by modified-gravity parameter extract TLNs uniquely analytic continuation multipole index ℓ to non-integer values. For stealth...
The excitation factors of black hole quasinormal modes quantify the ease and are independent source perturbation. We compute Kerr holes up to 20th overtone find that fourth, fifth, sixth overtones have first three highest for intermediate high spin parameters. This provides an confirmation importance has been confirmed by fitting data analysis numerical relativity waveforms beginning around strain peak amplitude.
LISA, the Laser Interferometer Space Antenna, will usher in a new era gravitational-wave astronomy. As first anticipated space-based detector, it expand our view to millihertz sky, where spectacular variety of interesting sources abound: from millions ultra-compact binaries Galaxy, mergers massive black holes at cosmological distances; beginnings inspirals that venture into ground-based detectors' death spiral compact objects holes, and many between. Central realising LISA's discovery...
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...
We discuss vacuum decays catalyzed by spherical and horizonless objects show that an ultra compact object could catalyze a decay around it within the cosmological time. The catalytic effect of be more efficient than black hole since in this case there is no suppression rate due to decrement its Bekestein entropy. If exists another minimum with AdS Higgs potential at high energy scale, abundance such as monopoles, neutron stars, axion oscillons, Q-balls, remnants, gravastars so on, severely...
A bstract We investigate a vacuum decay around spinning seed black hole by using the Israel junction condition and conclude that spin of would suppress rate compared to for non-spinning case, provided surface bubble has its ellipsoidal shape characterized Kerr geometry. also find out in existence near-extremal hole, false state can be more stabilized than case Coleman-de Luccia solution. few necessary assumptions carry calculations are discussed.
A bstract False vacuum decay is a key feature in quantum field theories and exhibits distinct signature the early Universe cosmology. It has recently been suggested that false catalyzed by black hole (BH), which might cause catastrophe of Standard Model Higgs if primordial BHs are formed Universe. We investigate phase transition scalar around radiating BH with taking into account effect Hawking radiation. find rate slightly decreases presence thermal since potential stabilized near horizon....
Static oscillating bounces in Schwarzschild de Sitter spacetime are investigated. The bounce with many oscillations gives a super-thick bubble wall, for which the total vacuum energy increases while mass of black hole decreases due to conservation Arnowitt-Deser-Misner (ADM) mass. We show that transition rate such an "up-tunneling" consuming seed is higher than Hawking-Moss transition. correspondence analyses static and global coordinates Euclidean space also
Recently, it has been proposed that the black hole greybody factors can be important to model ringdown spectral amplitudes. We study stability of against a small-bump correction in perturbation equation. find (I) factor is stable frequency region relevant and (II) destabilized at higher frequencies, especially for sharper bump correction. This behavior similar case overtones, which also very sensitive small clarify this (in)stability with WKB analysis. As main part ringdown, we conclude...
We discuss a two-step mechanism to create new inflationary domain beyond wormhole throat which is created by phase transition around an evaporating black hole. The first step creation of false vacuum bubble with thin-wall boundary the thermal effects Hawking radiation. Then this wall induces quantum tunneling wormhole-like configuration. As space can expand exponentially, being filled energy, may be interpreted as another universe in final stage hole evaporation.
Searches for gravitational wave echoes in the aftermath of mergers and/or formation astrophysical black holes have recently opened a novel and surprising window into quantum nature their horizons. Similar to astro- helioseismology, study spectrum provides promising method understand inner structure, what we call hole seismology. We provide detailed numerical analytic description this terms properties Kerr spacetime horizons, showing that it drastically differs from classical counterparts....
We apply the Lorentzian path integral to decay of a false vacuum and estimate false-vacuum rate. To make convergent, deformation an contour is performed by following Picard-Lefschetz theory. show that nucleation rate critical bubble, for which corresponding bounce action extremized, has same exponent as Euclidean approach. also extend our computation bubble larger or smaller than one formalism not applicable.
The measurability of multiple quasinormal (QN) modes, including overtones and higher harmonics, with the Laser Interferometer Space Antenna is investigated by computing gravitational wave (GW) signal induced an intermediate or extreme mass ratio merger involving a supermassive black hole (SMBH). We confirm that ringdown rapidly spinning holes are long-lived, harmonics significantly excited for mergers small ratios. investigate separability QN modes such demonstrate observation GWs from...
The Standard Model of particle physics predicts the speed light to be a universal propagation massless carriers. However, other possibilities exist---including Lorentz-violating theories---where different fundamental fields travel at speeds. Black holes are interesting probes such physics, as distinct would probe horizons. Here, we build an exact spacetime for two interacting scalar which have One these is able black hole interior other, giving rise energy extraction from and characteristic...
Abstract We compute the Quasi-Normal Mode (QNM) frequencies for scalar perturbations modified Schwarzschild black holes in Loop Quantum Gravity. study singularity-free polymerized metric characterized by two parameters encoding loop quantum effects: minimal area gap a 0 and polymeric deformation parameter P . perform numerical computations using Leaver's continued fraction method compare our results to other semi-analytical methods existing literature. effects on QNM spectrum of variation...
Einstein's vierbein formulation of general relativity based on the notion distant parallelism (teleparallelism) naturally introduces a covariant surface term in addition to Einstein-Hilbert action. We investigate action principle teleparallelism with existence spacetime boundaries and find that exactly eliminates all unwanted terms reside metric relativity, role Gibbons-Hawking-York (GHY) term. The identity such GHY is further confirmed by recovery correct black hole entropy from free energy...
We investigate the evaporation process of a Kerr–de Sitter black hole with Unruh–Hawking-like vacuum state, which is realistic state modelling originating from gravitational collapse. also compute greybody factors for gravitons, photons, and conformal-coupling massless scalar particles by using analytic solutions Teukolsky equation in background. It turns out that cosmological constant quenches amplification factor it approaches to zero towards critical point where Nariai extremal limits...