Sharp higher-order $L^2$-asymptotic expansion of solutions to σ-evolution equations with different damping types
Dinh Van Duong, Tuan Anh Dao
TL;DR
The paper analyzes high-order $L^2$-asymptotic expansions for linear $\sigma$-evolution equations with double damping, identifying how the coexisting parabolic-like damping $(-\Delta)^{\sigma_1}u_t$ and $\sigma$-evolution-like damping $(-\Delta)^{\sigma_2}u_t$ shape long-time behavior. It constructs $k$-th order asymptotic profiles via explicit Fourier multipliers $\mathcal{A}_0^k,\mathcal{A}_1^k$ (and $\mathcal{B}_0^k,\mathcal{B}_1^k$ for $\sigma_1=0$) and proves sharp $L^2$-decay rates for the remainder with detailed low-/high-frequency analyses. The results reveal the roles of $\sigma$, $\sigma_1$, and $\sigma_2$ in determining the decay and diffusion-like features, including precise lower bounds when the data have nonzero mean $P_1$. The approach advances understanding of the interplay between parabolic and hyperbolic damping mechanisms in fractional-diffusion-type models and provides tools for sharp long-time approximations in the $L^2$ setting.
Abstract
In this paper, our main goal is to achieve the high-order asymptotic expansion of solutions to $σ$-evolution equations with different damping types in the $L^2$ framework. Throughout this, we observe the influence of parabolic like models corresponding to $σ_1 \in [0, σ/2)$ and $σ$-evolution like models corresponding to $σ_2 \in (σ/2, σ]$ on the asymptotic behavior of solutions.
