Simulations of Mpemba effect in water and Lennard-Jones models

Understanding why hotter water can freeze faster than colder water — a phenomenon known as the Mpemba effect — is important for gaining deeper insights into systems far from equilibrium. Despite growing interest, this effect has not been demonstrated in computer simulations of ice formation. Using the TIP4P/Ice model, we show that the Mpemba effect appears in our simulated systems and observe its manifestation also during fluid-to-solid transitions in the case of simpler Lennard-Jones systems. We extend this investigation to magnetic transitions, revealing that the effect can arise from different mechanisms: for the TIP4P/Ice model, the effect arises from how long the system remains in a metastable state, while for other systems, it results from differences in critical fluctuations in the initial states. These findings suggest a universal behavior and are contrary to the common belief that metastability is a necessary requirement. The Mpemba effect — the counterintuitive phenomenon where a hotter system can freeze more rapidly than a cooler one — challenges conventional thermodynamic principles and stimulates ongoing inquiry. Using molecular dynamics simulations, this study demonstrates the Mpemba effect during ice formation in the TIP4P/Ice model, as well as for a similar transition in a Lennard-Jones model, and investigates the roles of metastability and critical fluctuations