5 papers
Quantum decoherence in the Caldeira-Leggett model by the real-time path integral on a computer
Jun Nishimura, Hiromasa Watanabe
We propose first-principle calculations of an open system based on the real-time path integral formalism treating the environment as well as the system of our interest together on…
Monte Carlo studies of the emergent spacetime in the polarized IKKT model
Chien-Yu Chou, Jun Nishimura, Cheng-Tsung Wang
The IKKT matrix model has been investigated as a promising nonperturbative formulation of superstring theory. One of the recent developments concerning this model is the discovery…
Quantum decoherence from complex saddle points
Jun Nishimura, Hiromasa Watanabe
Quantum decoherence is the effect that bridges quantum physics to well-understood classical physics. As such, it plays a crucial role in understanding the mysterious nature of quan…
Inequivalence between the Euclidean and Lorentzian versions of the type IIB matrix model from Lefschetz thimble calculations
Chien-Yu Chou, Jun Nishimura, Ashutosh Tripathi
The type IIB matrix model is conjectured to describe superstring theory nonperturbatively in terms of ten bosonic traceless Hermitian matrices ($μ=0, \ldots ,…
Monte Carlo studies of quantum cosmology by the generalized Lefschetz thimble method
Chien-Yu Chou, Jun Nishimura
Quantum cosmology aims at elucidating the beginning of our Universe. Back in early 80's, Vilenkin and Hartle-Hawking put forward the "tunneling from nothing" and "no boundary" prop…