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arXiv 2305.04068math.PR
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带Hölder噪声系数的随机波动方程:适定性与小质量极限

Stochastic wave equation with Hölder noise coefficient: well-posedness and small mass limit

Yi Han

AI总结:

本文构造了带Hölder连续噪声系数的阻尼随机波动方程的唯一鞅解,并证明当质量参数趋于零时其依分布收敛到随机热方程的解,验证了Smoluchowski-Kramers近似。

摘要:

我们构造了阻尼随机波动方程$$ μ\frac{\partial^2u}{\partial t^2}(t,x)=Δu(t,x)-\frac{\partial u}{\partial t}(t,x)+b(t,x,u(t,x))+σ(t,x,u(t,x))\frac{dW_t}{dt}$$的唯一鞅解,其中$Δ$是$[0,1]$上带Dirichlet边界条件的Laplacian算子,$W$是时空白噪声,$σ$关于$u$是$\frac{3}{4}+ε$-Hölder连续的且一致非退化,$b$具有线性增长。同样的构造也适用于无阻尼项的随机波动方程。更一般地,该构造适用于定义在可分Hilbert空间上、具有稠密定义算子$A$的SPDE,且对噪声系数假定的Hölder正则性以定量方式依赖于$A$的特征值。我们进一步证明了Smoluchowski-Kramers近似的有效性:假设$b$关于$u$是Hölder连续的,则当$μ$趋于$0$时,阻尼随机波动方程的解在连续路径空间上依分布收敛到相应随机热方程的解。后一结果即使在加性噪声情形下也是新的。

英文摘要:

We construct unique martingale solutions to the damped stochastic wave equation $$ μ\frac{\partial^2u}{\partial t^2}(t,x)=Δu(t,x)-\frac{\partial u}{\partial t}(t,x)+b(t,x,u(t,x))+σ(t,x,u(t,x))\frac{dW_t}{dt},$$ where $Δ$ is the Laplacian on $[0,1]$ with Dirichlet boundary condition, $W$ is space-time white noise, $σ$ is $\frac{3}{4}+ε$ -Hölder continuous in $u$ and uniformly non-degenerate, and $b$ has linear growth. The same construction holds for the stochastic wave equation without damping term. More generally, the construction holds for SPDEs defined on separable Hilbert spaces with a densely defined operator $A$, and the assumed Hölder regularity on the noise coefficient depends on the eigenvalues of $A$ in a quantitative way. We further show the validity of the Smoluchowski-Kramers approximation: assume $b$ is Hölder continuous in $u$, then as $μ$ tends to $0$ the solution to the damped stochastic wave equation converges in distribution, on the space of continuous paths, to the solution of the corresponding stochastic heat equation. The latter result is new even in the case of additive noise.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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