Quantum System Resists Heating Despite Continuous External Driving

A quantum system subjected to relentless external force has defied classical physics by remaining cold and orderly—a phenomenon rooted in quantum coherence rather than random thermalization.

Scientists at the University of Innsbruck observed a system of strongly interacting atoms that ceased absorbing energy after repeated laser "kicks", contrary to classical expectations of heating.

This behavior emerged in a state termed many-body dynamical localization (MBDL), where quantum coherence "freezes" motion in momentum space.

"In this state, quantum coherence and many-body entanglement prevent the system from thermalizing and from showing diffusive behavior, even under sustained external driving," explains Hanns Christoph Nägerl.

The team found that introducing randomness to the laser sequence disrupted MBDL, causing the system to resume energy absorption and thermalize. Lead author Yanliang Guo notes, "We had initially expected that the atoms would start flying all around. Instead, they behaved in an amazingly orderly manner."

The study, published in Science on January 8, 2026, challenges assumptions about driven quantum systems.

While the results demonstrate how coherence can stabilize quantum states against external perturbations, the researchers caution that the long-term stability of MBDL remains unproven.

Funding came from the Austrian Science Fund FWF, the European Union, and other institutions.