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Haruya Mizutani

Publications and source records attributed to Haruya Mizutani.

33 records · Page 2Linked to original sources
arXiv2020

Remarks on asymptotic order for the linear wave equation with the scale-invariant damping and mass with $L^r$-data

In the present paper, we consider the linear wave equation with the scale-invariant damping and mass. It is known that the global behavior of the solution depends on the size of the coefficients in front of the damping and mass at initial time $t=0$. Indeed, the solution satisfies the similar decay estimate to that of the corresponding heat equation if it is large and to that of the modified wave equation if it is small. In our previous paper, we obtain the scattering result and its asymptotic order for the data in the energy space $H^1\times L^2$ when the coefficients are in the wave regime. In fact, the threshold of the coefficients relies on the spatial decay of the initial data. Namely, it varies depending on $r$ when the initial data is in $L^r$ ($1\leq r < 2$). In the present paper, we will show the scattering result and the asymptotic order in the wave regime for $L^r$-data, which is wider than the wave regime for the data in the energy space. Moreover, we give an improvement of the asymptotic order obtained in our previous paper for the data in the energy space.

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arXiv2019

Uniform resolvent estimates for Schrödinger operator with an inverse-square potential

We study the uniform resolvent estimates for Schrödinger operator with a Hardy-type singular potential. Let $\mathcal{L}_V=-Δ+V(x)$ where $Δ$ is the usual Laplacian on $\mathbb{R}^n$ and $V(x)=V_0(θ) r^{-2}$ where $r=|x|, θ=x/|x|$ and $V_0(θ)\in\mathcal{C}^1(\mathbb{S}^{n-1})$ is a real function such that the operator $-Δ_θ+V_0(θ)+(n-2)^2/4$ is a strictly positive operator on $L^2(\mathbb{S}^{n-1})$. We prove some new uniform weighted resolvent estimates and also obtain some uniform Sobolev estimates associated with the operator $\mathcal{L}_V$.

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arXiv2019

Failure of scattering to standing waves for a Schrödinger equation with long-range nonlinearity on star graph

We consider the Schrödinger equation with power type long-range nonlinearity on star graph. Under a general boundary condition at the vertex, including Kirchhoff, Dirichlet, $δ$, or $δ'$ boundary condition, we show that the non-trivial global solution does not scatter to standing waves. Our proof is based on the argument by Murphy and Nakanishi, who treated the long-range nonlinear Schrödinger equation with a general potential in the Euclidean space, in order to consider general boundary conditions.

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arXiv2019

Wave operators on Sobolev spaces

We provide a simple sufficient condition in an abstract framework to deduce the existence and completeness of wave operators (resp. modified wave operators) on Sobolev spaces from the existence and completeness of the usual wave operators (resp. modified wave operators). We then give some examples of Schrödinger operators to which our abstract result applies. An application to scattering theory for the nonlinear Schrödinger equation with a potential is also given.

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arXiv2019

Uniform Sobolev estimates for Schrödinger operators with scaling-critical potentials and applications

We prove uniform Sobolev estimates for the resolvent of Schrödinger operators with large scaling-critical potentials without any repulsive condition. As applications, global-in-time Strichartz estimates including some non-admissible retarded estimates, a Hörmander type spectral multiplier theorem, and Keller type eigenvalue bounds with complex-valued potentials are also obtained.

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arXiv2017

Remarks on endpoint Strichartz estimates for Schrödinger equations with the critical inverse-square potential

The purpose of this paper is to study the validity of global-in-time Strichartz estimates for the Schrödinger equation on $\mathbb{R}^n$, $n\ge3$, with the negative inverse-square potential $-σ|x|^{-2}$ in the critical case $σ=(n-2)^2/4$. It turns out that the situation is different from the subcritical case $σ<(n-2)^2/4$ in which the full range of Strichartz estimates is known to be hold. More precisely, splitting the solution into the radial and non-radial parts, we show that (i) the radial part satisfies a weak-type endpoint estimate, which can be regarded as an extension to higher dimensions of the endpoint Strichartz estimate with radial data for the two-dimensional free Schrödinger equation; (ii) other endpoint estimates in Lorentz spaces for the radial part fail in general; (iii) the non-radial part satisfies the full range of Strichartz estimates.

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arXiv2017

Global-in-time smoothing effects for Schrödinger equations with inverse-square potentials

The purpose of this note is to prove global-in-time smoothing effects for the Schrödinger equation with potentials exhibiting critical singularity. A typical example of admissible potentials is the inverse-square potential $a|x|^{-2}$ with $a>-(n-2)^2/4$. This particularly gives an affirmative answer to a question raised by Bui-D'Ancona-Duong-Li-Ly [4]. The proof employs a uniform resolvent estimate proved by Barceló-Vega-Zubeldia [1] and an abstract perturbation method by Bouclet-Mizutani [3].

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arXiv2016

Eigenvalue bounds for non-self-adjoint Schrödinger operators with the inverse-square potential

The purpose of this paper is to study spectral properties of non-self-adjoint Schrödinger operators $-Δ-\frac{(n-2)^2}{4|x|^{2}}+V$ on $\mathbb{R}^n$ with complex-valued potentials $V\in L^{p,\infty}$, $p>n/2$. We prove Keller type inequalities which measure the radius of a disc containing the discrete spectrum, in terms of the $L^{p,\infty}$ norm of $V$. Similar inequalities also hold if the inverse-square potential is replaced by a large class of subcritical potentials with critical singularities at the origin. The main new ingredient in the proof is the uniform Sobolev inequality of Kenig-Ruiz-Sogge type for Schrödinger operators with strongly singular potentials, which is of independent interest.

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arXiv2016

Uniform resolvent and Strichartz estimates for Schrödinger equations with critical singularities

This paper deals with global dispersive properties of Schrödinger equations with real-valued potentials exhibiting critical singularities, where our class of potentials is more general than inverse-square type potentials and includes several anisotropic potentials. We first prove weighted resolvent estimates, which are uniform with respect to the energy, with a large class of weight functions in Morrey-Campanato spaces. Uniform Sobolev inequalities in Lorentz spaces are also studied. The proof employs the iterated resolvent identity and a classical multiplier technique. As an application, the full set of global-in-time Strichartz estimates including the endpoint case is derived. In the proof of Strichartz estimates, we develop a general criterion on perturbations ensuring that both homogeneous and inhomogeneous endpoint estimates can be recovered form resolvent estimates. Finally, we also investigate uniform resolvent estimates for long range repulsive potentials with critical singularities by using an elementary version of the Mourre theory.

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arXiv2016

Global in time Strichartz inequalities on asymptotically flat manifolds with temperate trapping

We prove global Strichartz inequalities for the Schrödinger equation on a large class of asymptotically conical manifolds. Letting $ P $ be the nonnegative Laplace operator and $ f_0 \in C_0^{\infty}({\mathbb R}) $ be a smooth cutoff equal to $1$ near zero, we show first that the low frequency part of any solution $ e^{-itP} u_0 $, i.e. $ f_0 (P) e^{-itP} u_0 $, enjoys the same global Strichartz estimates as on $ {\mathbb R}^n $ in dimension $ n \geq 3 $. We also show that the high energy part $ (1-f_0)(P) e^{-itP} u_0$ also satisfies global Strichartz estimates without loss of derivatives outside a compact set, even if the manifold has trapped geodesics but in a temperate sense. We then show that the full solution $ e^{-itP}u_0 $ satisfies global space-time Strichartz estimates if the trapped set is empty or sufficiently filamentary, and we derive a scattering theory for the $ L^2 $ critical nonlinear Schrödinger equation in this geometric framework.

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arXiv2015

Strichartz estimates for non elliptic Schrödinger equations on compact manifolds

In this note we consider the Schrödinger equation on compact manifolds equipped with possibly degenerate metrics. We prove Strichartz estimates with a loss of derivatives. The rate of loss of derivatives depends on the degeneracy of metrics. For the non-degenerate case we obtain, as an application of the main result, the same Strichartz estimates as that in the elliptic case. This extends Strichartz estimates for Riemannian metrics proved by Burq-Gérard-Tzvetkov to the non-elliptic case and improves the result by Salort. We also investigate the optimality of the result for the case on $\mathbb{S}^3\times \mathbb{S}^3$.

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arXiv2014

Strichartz estimates for Schrödinger equations with variable coefficients and unbounded potentials II. Superquadratic potentials

In this paper we prove local-in-time Strichartz estimates with loss of derivatives for Schrödinger equations with variable coefficients and potentials, under the conditions that the geodesic flow is nontrapping and potentials grow polynomially at infinity. This is a generalization to the case with variable coefficients and improvement of the result by Yajima-Zhang. The proof is based on microlocal techniques including the semiclassical parametrix for a time scale depending on a spatial localization and the Littlewood-Paley type decomposition with respect to both of space and frequency.

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arXiv2013

Strichartz estimates for Schrödinger equations with variable coefficients and unbounded potentials

The present paper is concerned with Schrödinger equations with variable coefficients and unbounded electromagnetic potentials, where the kinetic energy part is a long-range perturbation of the flat Laplacian and the electric (resp. magnetic) potential can grow subquadratically (resp. sublinearly) at spatial infinity. We prove sharp (local-in-time) Strichartz estimates, outside a large compact ball centered at origin, for any admissible pair including the endpoint. Under the nontrapping condition on the Hamilton flow generated by the kinetic energy, global-in-space estimates are also studied. Finally, under the nontrapping condition, we prove Strichartz estimates with an arbitrarily small derivative loss without asymptotic flatness on the coefficients.

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arXiv2011

Strichartz estimates for Schrödinger equations with variable coefficients and potentials at most linear at spatial infinity

In the present paper we consider Schrödinger equations with variable coefficients and potentials, where the principal part is a long-range perturbation of the flat Laplacian and potentials have at most linear growth at spatial infinity. We then prove local-in-time Strichartz estimates, outside a large compact set centered at origin, expect for the endpoint. Moreover we also prove global-in-space Strichartz estimates under the non-trapping condition on the Hamilton flow generated by the kinetic energy.

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