Journal of Spectral Theory 11(1) 355-367 2021年3月 [査読有り]
The norm resolvent convergence of discrete Schrödinger operators to a
continuum Schrödinger operator in the continuum limit is proved under
relatively weak assumptions. This result implies, in particular, the
convergence of the spectrum with r...
Pure and Applied Analysis 2(4) 861-873 2020年12月 [査読有り]
The resonances for the Wigner-von Neumann type Hamiltonian are defined by the
periodic complex distortion in the Fourier space. Also, following Zworski, we
characterize resonances as the limit points of discrete eigenvalues of the
Hamiltonian with...
The spectral shift function of a pair of self-adjoint operators is expressed via an abstract operator-valued Titchmarsh–Weyl m-function. This general result is applied to different self-adjoint realizations of second-order elliptic partial differe...
Let be the spacetime, where is a closed manifold
equipped with a Riemannian metric , and we consider a symmetric Klein-Gordon
type operator on , which is asymptotically converges to
a...
Here we discuss a new simplified proof of the essential self-adjointness for
formally self-adjoint differential operators of real principal type, previously
proved by Vasy (2020) and Nakamura-Taira (2021). For simplicity, here we
discuss the secon...
Pavel Exner   Shu Nakamura   Yukihide Tadano   
2022年2月
We consider the quantum graph Hamiltonian on the square lattice in Euclidean
space, and we show that the spectrum of the Hamiltonian converges to the
corresponding Schrödinger operator on the Euclidean space in the continuum
limit, and that the ...
We propose a method of data quantization of finite discrete-time signals
which optimizes the error estimate of low frequency Haar coefficients. We also
discuss the error/noise bounds of this quantization in the Fourier space. Our
result shows one ...
We consider scattering matrix for Schr\"odinger-type operators on with<br />
perturbation as . We show that<br />
the scattering matrix (with time-independent modifiers) is a pseudodifferent...