Past exam of the mathematics course of the University of Cambridge 2022 iii Paper 356 2 d Solution 2026-09-28
In the low-temperature regime, the particle rapidly equilibrates near a minimum and only rarely crosses a neighboring maximum. Applying Laplace's method to the exact current formula gives the Kramers escape ratesEach right or left escape changes position by , henceThe reduced continuous-time random walk on minima has off-diagonal transition ratesand diagonal generator entry . Its residence time in each well is exponentially distributed with rate , and the next jump is right with probability .