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Tunneling between multiple histories as a solution to the information loss paradox
Pisin Chen, Misao Sasaki, Dong-han Yeom +1
The information loss paradox associated with black hole Hawking evaporation is an unresolved problem in modern theoretical physics. In a recent brief essay, we revisited the the ev…
Resolving information loss paradox with Euclidean path integral
Pisin Chen, Misao Sasaki, Dong-han Yeom +1
The information loss paradox remains unresolved ever since Hawking's seminal discovery of black hole evaporation. In this essay, we revisit the entanglement entropy via Euclidean p…
Primordial black hole formation from massless scalar isocurvature
Chul-Moon Yoo, Tomohiro Harada, Shin'ichi Hirano +2
We numerically study the primordial black hole (PBH) formation by an isocurvature perturbation of a massless scalar field on super Hubble scales in the radiation-dominated universe…
Approximate gauge independence of the induced gravitational wave spectrum
Guillem Domènech, Misao Sasaki
Gravitational waves (GWs) induced by scalar curvature fluctuations are an important source of the cosmological GW background and a crucial counterpart of the primordial black hole…
Gravitational wave constraints on the primordial black hole dominated early universe
Guillem Domènech, Chunshan Lin, Misao Sasaki
We calculate the gravitational waves (GWs) induced by the density fluctuations due to inhomogeneous distribution of primordial black holes (PBHs) in the case where PBHs eventually…
Induced gravitational waves as a probe of thermal history of the universe
Guillem Domènech, Shi Pi, Misao Sasaki
The scalar perturbation induced gravitational waves are a probe of the primordial density perturbation spectrum on small scales. In this paper, we show that they can also probe the…
A path(-integral) toward non-perturbative effects in Hawking radiation
Pisin Chen, Misao Sasaki, Dong-han Yeom
Hawking's seminal discovery of black hole evaporation was based on the semi-classical, perturbative method. Whether black hole evaporation may result in the loss of information rem…
Could the black hole singularity be a field singularity?
Guillem Domènech, Atsushi Naruko, Misao Sasaki +1
In the wake of interest to find black hole solutions with scalar hair, we investigate the effects of disformal transformations on static spherically symmetric space-times with a no…
Primordial Tensor Perturbation in Double Inflationary Scenario with a Break
Shi Pi, Misao Sasaki, Ying-li Zhang
We study the primordial tensor perturbation produced from the double inflationary scenario with an intermediate break stage. Because of the transitions, the power spectrum deviates…
Possible resolution of a spacetime singularity with field transformations
Atsushi Naruko, Chul-Moon Yoo, Misao Sasaki
It is widely believed that classical gravity breaks down and quantum gravity is needed to deal with a singularity. We show that there is a class of spacetime curvature singularitie…
The effects of anisotropy and non-adiabaticity on the evolution of comoving curvature perturbation
Atsushi Naruko, Antonio Enea Romano, Misao Sasaki +1
We derive the equation for the evolution of the curvature perturbation on the comoving time slice, , in the presence of anisotropic and non-adiabatic terms in the en…
The status of KAGRA underground cryogenic gravitational wave telescope
KAGRA Collaboration, T. Akutsu, M. Ando +146
KAGRA is a 3-km interferometric gravitational wave telescope located in the Kamioka mine in Japan. It is the first km-class gravitational wave telescope constructed underground to…
Observational signatures of the parametric amplification of gravitational waves during reheating after inflation
Sachiko Kuroyanagi, Chunshan Lin, Misao Sasaki +1
We study the evolution of Gravitational Waves (GWs) during and after inflation as well as the resulting observational consequences in a Lorentz-violating massive gravity theory wit…
Hamiltonian approach to 2nd order gauge invariant cosmological perturbations
Guillem Domènech, Misao Sasaki
In view of growing interest in tensor modes and their possible detection, we clarify the definition of tensor modes up to 2nd order in perturbation theory within the Hamiltonian fo…
Thermal activation of thin-shells in anti-de Sitter black hole spacetime
Pisin Chen, Guillem Domènech, Misao Sasaki +1
We investigate thermal activation of thin-shells around anti-de Sitter black holes. Under the thin-shell approximation, we extensively study the parameter region that allows a bubb…
Action growth of charged black holes with a single horizon
Rong-Gen Cai, Misao Sasaki, Shao-Jiang Wang
According to the conjecture "complexity equals action," the complexity of a holographic state is equal to the action of a Wheeler-DeWitt (WDW) patch of black holes in anti-de Sitte…
Global adiabaticity and non-Gaussianity consistency condition
Antonio Enea Romano, Sander Mooij, Misao Sasaki
In the context of single-field inflation, the conservation of the curvature perturbation on comoving slices, , on super-horizon scales is one of the assumptions necessary to…
Stationary bubbles: information loss paradox?
Guillem Domènech, Misao Sasaki
The main purpose of this work is to build classically stationary bubbles, within the thin-shell formalism, which are unstable under quantum effects; they either collapse into a bla…
Conformal frames in cosmology
Guillem Domènech, Misao Sasaki
From higher dimensional theories, e.g. string theory, one expects the presence of non-minimally coupled scalar fields. We review the notion of conformal frames in cosmology and emp…
Adiabaticity and gravity theory independent conservation laws for cosmological perturbations
Antonio Enea Romano, Sander Mooij, Misao Sasaki
We carefully study the implications of adiabaticity for the behavior of cosmological perturbations. There are essentially three similar but different definitions of non-adiabaticit…
Perturbed Newtonian description of the Lemaître model with non-negligible pressure
Kazuhiro Yamamoto, Valerio Marra, Viatcheslav Mukhanov +1
We study the validity of the Newtonian description of cosmological perturbations using the Lemaitre model, an exact spherically symmetric solution of Einstein's equation. This prob…
Cosmological disformal invariance
Guillem Domènech, Atsushi Naruko, Misao Sasaki
The invariance of physical observables under disformal transformations is considered. It is known that conformal transformations leave physical observables invariant. However, whet…
Multi-disformal invariance of nonlinear primordial perturbations
Yuki Watanabe, Atsushi Naruko, Misao Sasaki
We study disformal transformations of the metric in the cosmological context. We first consider the disformal transformation generated by a scalar field and show that the curva…
Conformal Frame Dependence of Inflation
Guillem Domènech, Misao Sasaki
Physical equivalence between different conformal frames in scalar-tensor theory of gravity is a known fact. However, assuming that matter minimally couples to the metric of a parti…