Observation of quantum strong Mpemba effect.

Zhang, Jie; Xia, Gang; Wu, Chun-Wang; Chen, Ting; Zhang, Qian; Xie, Yi; Su, Wen-Bo; Wu, Wei; Qiu, Cheng-Wei; Chen, Ping-Xing; Li, Weibin; Jing, Hui; Zhou, Yan-Li

An ancient and counterintuitive phenomenon known as the Mpemba effect (water can cool faster when initially heated up) showcases the critical role of initial conditions in relaxation processes. How to realize and utilize this effect for speeding up relaxation is an important but challenging task in purely quantum system till now. Here, we experimentally study the strong Mpemba effect in a single trapped ion system in which an exponentially accelerated relaxation in time is observed by preparing an optimal quantum initial state with no excitation of the slowest decaying mode. Also, we demonstrate that the condition of realizing such effect coincides with the Liouvillian exceptional point, featuring the coalescence of both the eigenvalues and the eigenmodes of the systems. Our work provides an efficient strategy to engineer the dynamics of open quantum system, and suggests a link unexplored yet between the Mpemba effect and the non-Hermitian physics. The Mpemba effect is an archetype for various anomalous relaxation phenomena. Here, the authors experimentally study a quantum version of the Mpemba effect in a single trapped ion system, where relaxation is exponentially accelerated by removing the excitation of the slowest decaying mode. This phenomenon, seen in Markovian open quantum systems containing Liouvillian exceptional points, indicates a link between the Mpemba effect and non-Hermitian physics.

ION traps; QUANTUM theory; RELAXATION phenomena; QUANTUM states; PHYSICS

Nature Communications, 2025, Vol 16, Issue 1, p1

2041-1723

Academic Journal

10.1038/s41467-024-54303-0