A Martinez   S Nakamura   Sordoni, V   
JOURNAL OF FUNCTIONAL ANALYSIS 191(2) 297-317 2002年6月 [査読有り]
We prove exponentially small estimates on the off-diagonal terms of the scattering matrix associated to two-state semiclassical Schrodinger Hamiltonians. Our method is based on phase space tunneling estimates and a splitting of the operator by mea...
JM Combes   PD Hislop   F Klopp   S Nakamura   
PROCEEDINGS OF THE INDIAN ACADEMY OF SCIENCES-MATHEMATICAL SCIENCES 112(1) 31-53 2002年2月 [査読有り][招待有り]
The integrated density of states (IDS) for random operators is an important function describing many physical characteristics of a random system. Properties of the IDS are derived from the Wegner estimate that describes the influence of finite-vol...
JM Combes   PD Hislop   S Nakamura   
COMMUNICATIONS IN MATHEMATICAL PHYSICS 218(1) 113-130 2001年4月 [査読有り]
We develop the L-p-theory of the spectral shift function, for p greater than or equal to 1, applicable to pairs of self-adjoint operators whose difference is in the trace ideal I-p, for 0 < p less than or equal to 1. This result is a key ingred...
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...