33 citations · 39 across the 6 of their papers we have counts for
6 papers
Geometric deformations of symmetric spacetimes with a string cloud
Hiroshi Kozaki, Satsuki Matsuno, Tatsuhiko Koike +2
We establish a deformation framework for highly symmetric solutions to the Einstein equations. In this framework, four-dimensional metrics are constructed from three-dimensional η-…
Timescale for macroscopic equilibration in isolated quantum systems: a rigorous derivation for free fermions
Takashi Hara, Tatsuhiko Koike
For a class of translation-invariant free-fermion systems (including those with uniform nearest neighbor hopping) on a -dimensional hypercubic lattice…
Spacetime constructed from a contact manifold with a degenerate metric
Hiroshi Kozaki, Hideki Ishihara, Tatsuhiko Koike +1
We construct a four-dimensional spacetime using a three-dimensional contact manifold equipped with a degenerate metric. The degenerate metric is set to be compatible with the conta…
Distinguishability of countable quantum states and von Neumann lattice
Ryuitiro Kawakubo, Tatsuhiko Koike
Condition for distinguishability of countably infinite number of pure states by a single measurement is given. Distinguishability is to be understood as possibility of an unambiguo…
Spin Amplification with Inhomogeneous Broadening
Suguru Endo, Yuichiro Matsuzaki, William J. Munro +1
A long-lived qubit is usually well-isolated from all other systems and the environments, and so is not easy to couple with measurement apparatus. It is sometimes difficult to imple…
Time-Optimal Transfer of Coherence
A. Carlini, T. Koike
We provide exact analytical solutions for the problem of time-optimal transfer of coherence from one spin polarization to a three-fold coherence in a trilinear Ising chain with a f…