In a groundbreaking experimental achievement, a collaborative team from the Technical University of Munich (TUM), Princeton University, and Google Quantum AI has for the first time successfully realized and directly observed a novel category of non-equilibrium quantum matter known as a Floquet topologically ordered state. Leveraging the extraordinary capabilities of a 58-qubit superconducting quantum processor, the researchers ventured beyond conventional equilibrium physics to unveil behavior rooted in periodic quantum driving—phenomena that have eluded observation in traditional condensed matter systems for decades.
Unlike classical phases of matter such as solids, liquids, or magnets, which can be described by equilibrium thermodynamics and time-independent properties, non-equilibrium quantum phases are defined by their intrinsic dynamical behavior evolving over time. These phases exist in a regime where the system is continuously driven and does not settle into a thermodynamic equilibrium. To explore these complex regimes, the researchers utilized the framework of Floquet systems, named after Gaston Floquet, wherein quantum systems are subjected to rhythmic, periodic perturbations in time. This periodic driving can engender entirely new orders and emergent phenomena not accessible in static systems, leading to a profound rethinking of quantum matter classifications.
The realization of the Floquet topological order in this experiment involved intricate control over the qubit array to simulate a periodically driven quantum lattice system. The research team meticulously orchestrated the quantum gates and temporal sequences to engineer synthetic gauge fields, resulting in robust chiral edge modes that propagated directionally around the perimeter of the qubit network. Direct imaging of these directed edge currents provided compelling evidence of the underlying topological nature of the phase. Such manifestations stand in contrast to classical intuition, where edge-localized excitations move without backscattering, protected by the system’s topology.
To further probe the deeply nontrivial quantum topology encoded in the system, the team developed an innovative interferometric protocol designed to quantify the topological invariants and reveal the particle-like excitations’ transformative behaviors. This technique allowed the scientists to witness the dynamical transmutation of anyons—exotic quasiparticles characterized by fractional statistics that interpolate between fermions and bosons—a hallmark signature predicted for Floquet topological phases but never before experimentally seen. The interferometric measurements captured subtle quantum phase shifts linked to the braiding and fusion properties of these quasi-particles, providing unprecedented experimental access to non-equilibrium topological physics.
Quantum computers, often heralded as computational powerhouses for solving classically intractable problems, have now demonstrated their unique role as versatile quantum simulators and experimental laboratories. Melissa Will, PhD candidate at TUM, emphasized that realizing and exploring highly entangled non-equilibrium phases of matter is notoriously difficult for classical computational methods due to the exponential growth of the quantum state space. Quantum processors, however, by natively harnessing the principles of superposition and entanglement, offer an unparalleled platform to emulate complex quantum dynamics and probe frontier physics challenges, blurring the line between computation and experiment.
This breakthrough not only expands our fundamental understanding of quantum matter far from equilibrium but also paves the way for a new class of quantum technologies that exploit temporal periodicity and topology for robust information processing. The resilience of topological states to local perturbations offers tantalizing prospects for fault-tolerant quantum computation, where information is stored in global, non-local degrees of freedom immune to many types of noise. The ability to engineer and manipulate Floquet topological orders dynamically could revolutionize quantum device architectures and inspire novel materials with engineered quantum properties.
The experimental platform harnessed superconducting qubits arranged in a configuration enabling precise, high-fidelity control of both unitary evolution and measurement sequences. This combination of hardware sophistication and algorithmic innovation allowed the unprecedented direct observation of subtle quantum phenomena and their time-evolving nature. Notably, the capacity to perform time-resolved imaging and interferometric interrogation provided a richer classification toolbox beyond traditional equilibrium diagnostics such as order parameters, enabling researchers to capture purely dynamical topological fingerprints.
Contemporary condensed matter physics has long been captivated by topological phases, which provide a unifying framework for phases of matter distinguished not by symmetry breaking but by global topological invariants. The extension of these concepts into the non-equilibrium domain, particularly through periodic driving—Floquet engineering—has generated intense theoretical excitement. Yet, experimental realization and verification have been stymied by the complexity of crafting suitable platforms capable of sustaining coherence while implementing rapid, precise time-dependent control. This work decisively bridges that gap, providing experimental validation for theories that until now were purely phenomenological models.
The implications of these insights are broad and profound. By opening a window into out-of-equilibrium quantum matter, quantum simulation laboratories can address unanswered questions about thermalization processes, localization phenomena, and exotic quasiparticle dynamics in a controlled environment. Furthermore, the experimental methodologies developed here could inspire analogous studies in other physical systems, including cold atoms, photonic lattices, and solid-state spin ensembles, leading to a deeper universal understanding of non-equilibrium quantum phases.
On a conceptual level, the experiment challenges and enriches traditional paradigms that rely on equilibrium assumptions, highlighting the richness of quantum dynamical phases and their classification. The ability to dynamically tune system parameters and access exotic states offering new types of quantum correlations and entanglement structures underscores a paradigm shift, heralding a more versatile quantum science era. These advances foreshadow a future where quantum processors are not merely computational engines but essential experimental tools for probing uncharted quantum matter regimes.
The collaborative achievement exemplifies the synergy between experimental innovation, theoretical modeling, and scalable quantum hardware development. The partnership between leading academic institutions and cutting-edge industry research teams demonstrates how integrated, cross-disciplinary efforts accelerate discovery in frontiers of physics. As hardware improves toward larger qubit counts and improved coherence, the scope of feasible quantum simulations will broaden, enabling exploration of increasingly complex non-equilibrium phenomena with direct technological relevance.
Ultimately, this pioneering research marks a crucial milestone in quantum science, establishing quantum processors as authentic laboratories for studying intricate and exotic phases of matter far from equilibrium. Its success inspires confidence that many other yet unknown quantum states and transitions await discovery, promising not only profound scientific insights but also practical innovations for next-generation quantum technologies harnessing the power of time-dependent quantum engineering.
Subject of Research: Not applicable
Article Title: Probing Non-Equilibrium Topological Order on a Quantum Processor
News Publication Date: 10-Sep-2025
Web References: 10.1038/s41586-025-09456-3
References: Nature (journal publication)
Keywords: non-equilibrium quantum phases, Floquet topological order, quantum simulation, superconducting qubits, anyons, topological quantum matter, periodic driving, quantum processor, interferometric measurement, quantum dynamics
