Capture rate and efficiency of an oscillating non-ideal trap interacting with a sea of random diffusing particles. A non-equilibrium Fokker–Planck picture

• We analyzed the particles dynamics subject to an oscillating “trap”.
• Numerical solution to FPE with various trap's oscillating frequencies and amplitudes.
• Out-of-equilibrium calculations describe the evolution toward a “pseudo” equilibrium state.
• At pseudo-equilibrium state trapped particles density depends on frequency and amplitude.

We investigated the time evolution of a distribution of random diffusing particles around an oscillating non-ideal trap. The problem has been addressed by numerically solving a mono-dimensional Fokker–Planck equation (FPE) for a confined distribution of particles in the presence of an oscillating potential well (trap) of finite depth. Accurate numerical solutions of the FPE have been obtained and expressed as a function of the trap oscillation amplitudes and frequencies. Results show a marked influence of the oscillations both on the capture kinetics and trap efficiency in equilibrium conditions. All the calculated properties exhibit a saturation behavior both at high and low frequencies.