activity
20242026
collaborators

5 papers

gr-qc2026

Graviton-induced which-path decoherence in matter-wave interferometry

Hiroki Matsui

We derive which-path decoherence for matter-wave interferometry that arises from tracing out the gravitons of linearized quantum gravity. Because the gravitons are driven linearly…

hep-th2026

Squeezed Gravitons and One-Loop Self-Energy under Light-Cone Smearing

Hiroki Matsui

We investigate light-cone smearing induced by quantum fluctuations of gravitons and its implications for the ultraviolet structure of quantum field theory. By treating the first-or…

gr-qc2026

Casimir-Induced Quintessence in Dark Dimension

Tomoki Katayama, Hiroki Matsui, Yuri Michinobu +3

We investigate a concrete realization of the Dark Dimension scenario, where a single large extra dimension is set at sub-millimeter scales. In this framework, the Casimir energy of…

gr-qc2025

Resurgence in Lorentzian quantum cosmology: No-boundary saddles and resummation of quantum gravity corrections around tunneling saddle points

Masazumi Honda, Hiroki Matsui, Kazumasa Okabayashi +1

We revisit the path-integral approach to the wave function of the Universe by utilizing Lefschetz thimble analyses and resurgence theory. The traditional Euclidean path-integral of…

gr-qc2024

Jackiw-Teitelboim Gravity and Lorentzian Quantum Cosmology

Masazumi Honda, Hiroki Matsui, Kota Numajiri +1

We directly evaluate the probability amplitudes in Jackiw-Teitelboim (JT) gravity using the Lorentzian path integral formulation. By imposing boundary conditions on the scale facto…