Yoritaka Iwata

Fractional Powers of Operators: Characterization via $δ$-Regularized Logarithmic Representation

Yoritaka Iwata

For the fractional powers of operators, the classical formulation by V. Balakrishnan inherently requires positivity or specific sectorial conditions of the generator (i.e., the generation of analytic semigroups). To overcome these limitations, this paper presents a novel approach to constructing fractional powers …

Unbounded Generalization of the Baker–Campbell–Hausdorff Formulae

Yoritaka Iwata

ABSTRACT Based on the operator representation on the module over a Banach algebra, the Baker–Campbell–Hausdorff formula is generalized to be applicable to unbounded infinitesimal generators in Banach spaces. For this purpose, it is necessary to extract a bounded component from a given …

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Time-dependent finite-dimensional dynamical system representation of breather solutions

Yoritaka Iwata, Yasuhiro Takei

A concept of finite-dimensional dynamical system representation is introduced. Since the solution trajectory of partial differential equations are usually represented within infinite-dimensional dynamical systems, the proposed finite-dimensional representation provides decomposed snapshots of time evolution. Here we focus on analyzing the breather solutions …

Dynamical symmetry breaking described by cubic nonlinear Klein-Gordon equations

Yasuhiro Takei, Yoritaka Iwata

The dynamical symmetry breaking associated with the existence and non-existence of breather solutions is studied. Here, nonlinear hyperbolic evolution equations are calculated using a high-precision numerical scheme. %%% First, for clarifying the dynamical symmetry breaking, it is necessary to use a sufficiently …

Low-energy neutrino responses for 71Ga by electron capture rates, charge exchange reactions and shell model calculations

Yoritaka Iwata, H. Ejiri, Shahariar Sarkar

Weak Gamow-Teller (GT) responses for low-lying states in ${}^{71}\mathrm{Ga}$ are crucial for studying low-energy solar neutrinos and the Ga anomaly, i.e., the possible transition to the sterile state. The responses for the ground state, the first excited state, and the second excited …

0 ν β β decay of Xe 136 using the nonclosure approach in the nuclear shell model

Shahariar Sarkar, Yoritaka Iwata, Kanhaiya Jha, R. Chatterjee

In this investigation, we compute the nuclear matrix elements (NMEs) relevant to the light neutrino-exchange mechanism governing neutrinoless double beta ($0\ensuremath{\nu}\ensuremath{\beta}\ensuremath{\beta}$) decay in $^{136}\mathrm{Xe}$. Our method is based on the nonclosure approach within the interacting nuclear shell model framework. This approach considers …

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Recurrence formula for some higher order evolution equations

Yoritaka Iwata

Riccati’s differential equation is formulated as abstract equation in finite or infinite dimensional Banach spaces. Since the Riccati’s differential equation with the Cole–Hopf transform shows a relation between the first order evolution equations and the second order evolution equations, its generalization suggests …

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The study of $0νββ$ decay of $^{136}$Xe using nonclosure approach in nuclear shell model

Shahariar Sarkar, Yoritaka Iwata, Kanhaiya Jha, R. Chatterjee

In this investigation, we compute the nuclear matrix elements (NMEs) relevant to the light neutrino-exchange mechanism governing neutrinoless double beta ($0νββ$) decay in $^{136}$Xe. Our method is based on the nonclosure approach within the interacting nuclear shell model framework. This approach considers …

Besov空間における双曲型発展方程式 (関数空間を中心とした実解析・複素解析・函数解析の総合的研究)

Yoritaka Iwata

Besov空間上で双曲型抽象発展方程式を考える。Banach空間の非有界作用素に対する対数表現理論を用いることで、双曲型発展作用素の生成に関する定理を証明する。本稿で示される結果は、既存のBesov空間上で放物型抽象発展方程式論を、双曲型抽象発展方程式にまで適用できる形に拡張するものである。

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Proton and neutron density distributions at supranormal density in low- and medium-energy heavy-ion collisions. II. Central Pb + Pb collisions

J. R. Stone, Paweł Danielewicz, Yoritaka Iwata

This paper represents a continuation of our investigation into the limitations on total, proton, and neutron particle number densities, as well as the asymmetry of proton and neutron density distributions achievable in central heavy-ion collisions. We explore these aspects at low and …

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Calculation of nuclear matrix elements for 0 ν β β decay of Sn 124 using the nonclosure approach in the nuclear shell model

Shahariar Sarkar, P. K. Rath, V. Nanal, R. G. Pillay et autres

In this study, we calculate the nuclear matrix elements (NMEs) for the light neutrino-exchange mechanism of neutrinoless double beta decay ($0\ensuremath{\nu}\ensuremath{\beta}\ensuremath{\beta}$) of $^{124}\mathrm{Sn}$ within the framework of the interacting nuclear shell model, using the effective shell model Hamiltonian GCN5082. The NMEs are …

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Recurrence Formula for Any Order Evolution Equations

Yoritaka Iwata

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