The Gamma Expansion of the Level Two Large Deviation Rate Functional for Reversible Diffusion Processes

Fix a smooth Morse function $U\colon \mathbb{R}^{d}\to\mathbb{R}$ with finitely many critical points, and consider the solution of the stochastic differential equation \begin{equation*} d\boldsymbol{x}_ε(t)=-\nabla U(\boldsymbol{x}_ε(t))\,dt \,+\,\sqrt{2ε}\, d\boldsymbol{w}_{t}\,, \end{equation*}