An exotic phase of matter has been realized on a quantum processor.
Matter can exist in different forms, or phases, such as liquid water or solid ice. These phases are usually understood under equilibrium conditions, where everything remains stable over time. However, nature also permits much stranger possibilities: phases that appear only when a system is pushed out of equilibrium. A new study published in Nature demonstrates that quantum computers provide a powerful new tool for investigating these unusual states of matter.
In contrast to ordinary phases, non-equilibrium quantum phases are defined by how they change and evolve over time, a type of behavior that cannot be explained by standard equilibrium thermodynamics. A particularly intriguing example arises in Floquet systems (quantum systems that are driven in regular, repeating cycles). This periodic driving can produce entirely new types of order that do not exist under equilibrium conditions, uncovering phenomena far beyond what conventional phases of matter allow.
Using a 58 superconducting qubit quantum processor, the team from the Technical University of Munich (TUM), Princeton University, and Google Quantum AI realized a Floquet topologically ordered state, a phase that had been theoretically proposed but never before observed. They directly imaged the characteristic directed motions at the edge and developed a novel interferometric algorithm to probe the system’s underlying topological properties. This allowed them to witness the dynamical “transmutation” of exotic particles – a hallmark that has been theoretically predicted for these exotic quantum states.
Quantum computer as a laboratory
“Highly entangled non-equilibrium phases are notoriously hard to simulate with classical computers,” said the first author Melissa Will, PhD student at the Physics Department of the TUM School of Natural Sciences. “Our results show that quantum processors are not just computational devices – they are powerful experimental platforms for discovering and probing entirely new states of matter.”
This work opens the door to a new era of quantum simulation, where quantum computers become laboratories for studying the vast and largely unexplored landscape of out-of-equilibrium quantum matter. The insights gained from these studies could have far-reaching implications, from understanding fundamental physics to designing next-generation quantum technologies.
Reference: “Probing non-equilibrium topological order on a quantum processor” by M. Will, T. A. Cochran, E. Rosenberg, B. Jobst, N. M. Eassa, P. Roushan, M. Knap, A. Gammon-Smith and F. Pollmann, 10 September 2025, Nature.
DOI: 10.1038/s41586-025-09456-3
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