  An ancient and counterintuitive phenomenon know 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 report the first experiment, as far as
we know,about the strong Mpemba effect in a single trapped ion system in which
an exponentially expedited relaxation in time is observed by preparing an
optimal initial state with no excitation of the slowest decaying mode. Also, we
find 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 system. Our work provides an efficient strategy to
exponentially accelerate relaxations of quantum system to their stationary
state, and suggests a link unexplored yet between the Mpemba effect and the
non-Hermitian physics. It could open up the door to engineer a wide range of
dissipative quantum systems by utilizing the anomalous Mpemba effect, for
applications in quantum simulation and quantum information processing.
