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.
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.
