Experimental study of Mpemba effect in an energy Langevin system

We experimentally investigate the Mpemba effect, where a hot system cools faster than a colder one when quenched to the same low temperature, within a programmable energy Langevin system using optically levitated nanoparticles in vacuum. By constructing an asymmetric double-well energy effective potential, we systematically compare the relaxation dynamics of systems initialized at different temperatures and quenched to a cold equilibrium state. Energy trajectory analysis reveals fundamentally distinct cooling pathways: The hot state achieves rapid equilibration through barrier-free relaxation, while the warm state exhibits prolonged dynamics due to metastable trapping in local potential minima. Quantitative measurements of population redistribution show nonmonotonic cooling timescales governed by initial state-dependent barrier crossing probabilities. Further modulation of the potential confirms the exponential scaling of equilibration time with the well barrier height, in agreement with Kramers’s theory. This work establishes optical levitation as a powerful platform for investigating energy dynamics in nonequilibrium thermodynamics, providing a pathway for energy thermodynamic engineering applications, including microscopic heat engine and biomolecular structural transition simulations.