Brownian motion under intermittent harmonic potentials.

We study the effects of an intermittent harmonic potential of strength $\mu_0$ -- that switches on and off at a constant rate $\gamma$, on a Brownian particle. This can be thought of as a realistic model for realisation of stochastic resetting. We show that this dynamics admits a stationary solution in all parameter regimes and compute the full time dependent variance for the position distribution and find the characteristic relaxation time. We find the exact non-equilibrium stationary state distributions in the limits -- (i) $\gamma\ll\mu_0 $ which shows a non-trivial distribution, in addition as $\mu_0\to\infty$, we get back the result for resetting with refractory period; (ii) $\gamma\gg\mu_0$ where the particle relaxes to a Boltzmann distribution of an Ornstein-Uhlenbeck process with strength ($\mu_0/2$) and (iii) intermediate $\gamma=2n\mu$ for $n=2,4$. The mean first passage time (MFPT) to find a target located close to the minima of the potential exhibits an optimisation with the switching rate, however unlike instantaneous resetting the MFPT does not diverge but reaches a stationary value at large rates. MFPT also shows similar behavior with respect to the potential strength. Our results can be verified in experiments on colloids using optical tweezers.