11 citations · 23 across the 9 of their papers we have counts for
10 papers
Dimensional (In)dependence of Lorentzian Quantum Cosmology
Masazumi Honda, Hiroki Matsui, Kota Numajiri +2
We study transition amplitudes of the quantum universe in -dimensional spacetime within the de Sitter minisuperspace approximation in Einstein gravity. Using the Lorentzian path…
Exact DeWitt kernels in Lorentzian quantum cosmology
Hiroki Matsui
The DeWitt boundary condition can be implemented in the Lorentzian path integral of minisuperspace quantum cosmology by summing only over non-singular paths. In this paper, we pres…
Gravitational decoherence from soft-graviton -matrix
Hiroki Matsui
We revisit gravitational decoherence of matter superpositions using the leading soft sector of the graviton -matrix. Starting from Weinberg's soft theorem and the overlap of coh…
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…
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…
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…
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…
No smooth spacetime: Exploring primordial perturbations in Lorentzian quantum cosmology
Hiroki Matsui
Recent analysis of quantum cosmology has focused on the Lorentzian path integral formulations of both the no-boundary and tunneling proposals. However, it has been criticized that…
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…
Pauli-Villars regularization of Kaluza-Klein Casimir energy with Lorentz symmetry
Hiroki Matsui, Yutaka Sakamura
The Pauli-Villars regularization is appropriate to discuss the UV sensitivity of low-energy observables because it mimics how the contributions of new particles at high energies ca…