Quantum Leap to Calm express
In the quantum world, the path to calm sometimes resembles a paradoxical race: starting further from the finish, the system reaches equilibrium faster. This effect, a quantum analog of the Mpemba phenomenon, is due to the rapid growth of entropy — a measure of disorder. A strong push at the start seems to trigger an avalanche of changes that accelerates settling.
Scientists built a model based on the principle of maximum entropy growth, tracing back to Ludwig Boltzmann. By compressing the description from four to three dimensions, they achieved agreement with a laboratory three-level system. Machine learning revealed the key parameter governing the decay rate. Thus, a precise formula for the quantum 'shake' emerged.
This is not just theory: qubits will be able to reach the desired state faster after a short excitation. This engineering trick will shorten waiting times in future devices.
Original abstract
as written by the authors arXiv:2603.24522
The quantum Mpemba effect is a phenomenon characterized by an exponential relaxation from a non-equililbrium state to a steady state. This effect was predicted with an analysis of the Liouvillian superoperator and experimentally demonstrated in a three-level system. In this work, the system dynamics of the Mpemba effect is predicted within the steepest-entropy-ascent quantum thermodynamics framework considering a single constituent three-level isolated system. The system is projected from a four-dimensional Hilbert space onto a three-dimensional one using the Feshbach projection in order to compare the theoretical results with experimental data. Since the quantum Mpemba effect is characterized by a dissipative acceleration, the relaxation parameter, $$\tau_D$$, plays a fundamental rol in the dissipative dynamics predicted by the model and is determined using machine learning methods, resulting in a model that thermodynamically describes this phenomenon at the quantum level.
Aristotle described the rapid freezing of heated water, but the effect was named after Tanzanian schoolboy Erasto Mpemba: in 1963, he noticed that hot ice cream freezes faster.