A groundbreaking quantum discovery from researchers at the University of Innsbruck reveals that even when continuously agitated, a quantum system can resist heating, defying classical physics. This unexpected finding, detailed in a recent study, challenges the fundamental understanding of energy absorption in many-body systems and suggests a new realm of quantum stability.
In our everyday world, repeated force inevitably leads to heat. Rubbing hands together or striking metal generates warmth. This intuitive principle, that continuous energy input causes a rise in temperature, has long been a cornerstone of physics, expected to hold true even at the quantum scale.
However, recent experiments led by Hanns Christoph Nägerl’s group at the Department of Experimental Physics at the University of Innsbruck presented a startling contradiction. Their work demonstrates that strongly driven quantum systems do not always succumb to the expected thermalization, opening new avenues for understanding quantum mechanics.
A quantum gas that stops absorbing energy
The team engineered a one-dimensional quantum fluid, composed of strongly interacting atoms chilled to mere nanokelvin above absolute zero. They subjected these atoms to a rapidly pulsing laser lattice, effectively “kicking” them repeatedly. Classically, this constant driving should have led to continuous energy absorption, akin to a trampoline jumper gaining momentum.
Yet, the researchers observed a remarkable phenomenon: after an initial phase, the spread of the atoms’ momentum ceased. The system’s kinetic energy plateaued, refusing to increase further despite the ongoing external force. The atoms, though still interacting and driven, simply stopped absorbing energy, entering a state termed many-body dynamical localization (MBDL).
Hanns Christoph Nägerl explained this state: “In this state, quantum coherence and many-body entanglement prevent the system from thermalizing and from showing diffusive behavior, even under sustained external driving.” The momentum distribution effectively freezes, retaining its structure, as reported by ScienceDaily on January 8, 2026.
The critical role of quantum coherence
The scientists were initially surprised by the orderly outcome. Lead author Yanliang Guo admitted that this behavior ran counter to their predictions, stating, “Instead, they behaved in an amazingly orderly manner.” Lei Ying from Zhejiang University, a theory collaborator, highlighted the counter-intuitive nature: “What’s striking is the fact that in a strongly driven and strongly interacting system, many-body coherence can evidently halt energy absorption.”
To test the robustness of this unusual state, the researchers introduced randomness into the driving sequence. Even minimal disorder proved sufficient to destroy the localization. Once quantum coherence was disrupted, the atoms reverted to conventional behavior, their momentum spreading, and kinetic energy rapidly increasing without limit.
This experiment underscored the pivotal role of quantum coherence in preventing thermalization within such driven many-body systems, as Nägerl emphasized. The findings, which defy classical intuition, reveal a profound stability rooted in the unique principles of quantum mechanics.
This discovery of many-body dynamical localization extends far beyond theoretical physics, offering critical insights for future quantum technologies. Preventing unwanted heating is a significant hurdle in developing stable quantum computers and other sensitive quantum devices. Understanding how quantum systems can inherently resist disorder could pave the way for more robust and efficient quantum designs.
The University of Innsbruck’s research, supported by collaborations like that with Zhejiang University, provides a compelling testament to the bizarre yet powerful nature of quantum mechanics. It suggests that by harnessing quantum coherence, we might engineer systems that inherently maintain order and cool states, even under intense external forces.
