Kyoto researchers quantify the Mpemba effect using thermomajorization

Scientists have made progress in understanding the Mpemba effect, where hot substances can cool faster than colder ones. This phenomenon, most famously observed in water, has puzzled researchers for years. A team from Kyoto University has developed a new method to better quantify this effect. Their approach, based on thermomajorization theory, allows for a clearer comparison of thermodynamic states. This theory focuses on measuring disorder, or entropy, in different systems. Traditional ways of measuring relaxation speed led to inconsistencies in previous studies. The researchers' new method does not depend on any single measurement, which solves these ambiguities. They presented their findings in a recently published paper in Physical Review Letters. Co-author Tan Van Vu explained that their method evaluates all relevant measurement distances, offering a more unified approach. This means researchers can now assess the Mpemba effect consistently across various classical processes. The team's research also showed that the Mpemba effect could occur at any temperature, not just specific ones. Their findings could impact many areas, including the optimization of thermal processes in technologies like heat engines and refrigeration. Looking ahead, Vu and his colleague plan to apply their approach to more complex systems, including quantum systems. They hope to uncover deeper insights into the physics of thermal relaxation and tackle open questions, such as the minimum timescale for the Mpemba effect.