Linear fluctuating interface
= Linear fluctuating interface
{title2=$\partial_t h=\alpha\nabla^2h+\eta$}
A linear fluctuating interface smooths height gradients by diffusion and receives additive <Gaussian white noise>. With periodic or <Neumann boundary conditions>, its nonzero <Fourier modes> are independent <Ornstein-Uhlenbeck processes> if the noise is diagonal in that basis. The unconstrained uniform height is a <Brownian zero mode of a fluctuating interface>.