Slow-fast systems with stochastic resetting

In this paper we explore the effects of instantaneous stochastic resetting on a planar slow-fast dynamical system of the form $\dot{x}=f(x)-y$ and $\dot{y}=\epsilon (x-y)$ with $0<\epsilon \ll 1$. We assume that only the fast variable $x(t)$ resets to its initial state $x_0$ at a random sequence of times generated from a Poisson process of rate $r$. Fixing the slow variable, we determine the parameterized probability density $p(x,t|y)$, which is the solution to a modified Liouville equation. We then show how for $r\gg \epsilon$ the slow dynamics can be approximated by the averaged equation $dy/d\tau=\E[x|y]-y$ where $\tau=\epsilon t$, $\E[x|y]=\int x p^*(x|y)dx$ and $p^*(x|y)=\lim_{t\rightarrow \infty}p(x,t|y)$. We illustrate the theory for $f(x)$ given by the cubic function of the FitzHugh-Nagumo equation. We find that the slow variable typically converges to an $r$-dependent fixed point $y^*$ that is a solution of the equation $y^*=\E[x|y^*]$. Finally, we numerically explore deviations from averaging theory when $r=O(\epsilon)$.