Shinji Mukohyama

On the regularity of deformed extremal horizons

Francesco Di Filippo, Shinji Mukohyama, José M. M. Senovilla

A bstract It has recently been argued that extremal black holes can act as amplifiers of new physics, due to horizon instabilities that enhance the effects of ultraviolet corrections. In this paper, we revisit some of these claims and investigate the viability …

jp, es (code pays fourni par la source)

On the regularity of deformed extremal horizons

Francesco Di Filippo, Shinji Mukohyama, José M. M. Senovilla

Space vs time dependence in taming the infrared instability of projectable Hořava gravity

Shinji Mukohyama, Jury I. Radkovski, Sergey Sibiryakov

Minkowski spacetime exhibits infrared instability in projectable Hořava gravity in ( 3 + 1 ) dimensions. To be phenomenologically viable, the instability should be either hidden by other time-dependent processes such as the Hubble expansion of the universe and the Jeans instability, …

jp, es, ca (code pays fourni par la source)

Macroscopic backreaction of the trace anomaly on classical vacuum backgrounds

Raúl Carballo-Rubio, Francesco Di Filippo, Shinji Mukohyama, Kazumasa Okabayashi

We study the backreaction of quantum fields in the Boulware vacuum state on the Schwarzschild geometry, using the Riegert--Mottola--Vaulin renormalized stress-energy tensor derived from the conformal anomaly. An order-reduction procedure is applied to the first order, paying special attention to the conservation …

es, jp (code pays fourni par la source)

Quantum mechanics with a ghost: Counterexamples to spectral denseness

Cédric Deffayet, Atabak Fathe Jalali, Aaron Held, Shinji Mukohyama et autres

We quantise integrable point-particle systems with opposite-sign kinetic terms and nontrivial interactions. Using methods from separability theory, we show that previously determined classical stability conditions also imply discrete separated eigenvalue spectra. The resulting energy spectrum is unbounded above and below but not …

Unitary Time Evolution and Vacuum for a Quantum Stable Ghost

Cédric Deffayet, Atabak Fathe Jalali, Aaron Held, Shinji Mukohyama et autres

We quantize a classically stable system of a harmonic oscillator polynomially coupled to a ghost with negative kinetic energy. We prove that due to an integral of motion with a positive discrete spectrum: i) the Hamiltonian has a pure point spectrum unbounded …

Unitary Time Evolution and Vacuum for a Quantum Stable Ghost

Cédric Deffayet, Atabak Fathe Jalali, Aaron Held, Shinji Mukohyama et autres

We quantize a classically stable system of a harmonic oscillator polynomially coupled to a ghost with negative kinetic energy. We prove that due to an integral of motion with a positive discrete spectrum: i) the Hamiltonian has a pure point spectrum unbounded …

Burundi, fr, at, jp (code pays fourni par la source)

Quantum mechanics with a ghost: Counterexamples to spectral denseness

Cédric Deffayet, Atabak Fathe Jalali, Aaron Held, Shinji Mukohyama et autres

We quantise integrable point-particle systems with opposite-sign kinetic terms and nontrivial interactions. Using methods from separability theory, we show that previously determined classical stability conditions also imply discrete separated eigenvalue spectra. The resulting energy spectrum is unbounded above and below but not …

Burundi, fr, at, jp (code pays fourni par la source)

Emergent big bang scenario

C. Justin Feng, Shinji Mukohyama, Jean–Philippe Uzan

This paper proposes a new avenue for understanding the cosmological singularity. The standard cosmological model contains a generic initial singularity usually referred to as the big bang. Herein, we present a novel idea to extend the description of our Universe beyond this …

cz, jp, fr (code pays fourni par la source)

Linear higher-order Maxwell-Einstein-Scalar theories

Mohammad Ali Gorji, Shinji Mukohyama, Pavel Petrov, Masahide Yamaguchi

A bstract In the context of the Higher-Order Maxwell-Einstein-Scalar (HOMES) theories, which are invariant under spacetime diffeomorphisms and U(1) gauge symmetry, we study two broad subclasses: the first is up to linear in R μναβ , ∇ μ ∇ ν ϕ , …

kr, jp (code pays fourni par la source)

Space- vs Time-dependence in taming the infrared instability of projectable Hořava Gravity

Shinji Mukohyama, Jury I. Radkovski, Sergey SIBIRYAKOV

Minkowski spacetime exhibits infrared instability in projectable Ho\v rava gravity in (3+1) dimensions. To be phenomenologically viable, the instability should be either hidden by other time-dependent processes such as the Hubble expansion of the universe and the Jeans instability, or evolve into …

Space- vs Time-dependence in taming the infrared instability of projectable Hořava Gravity

Shinji Mukohyama, Jury Radkovski, Sergey SIBIRYAKOV

Minkowski spacetime exhibits infrared instability in projectable Ho\v rava gravity in (3+1) dimensions. To be phenomenologically viable, the instability should be either hidden by other time-dependent processes such as the Hubble expansion of the universe and the Jeans instability, or evolve into …