We are all familiar with the conventional phases of matter—solids and liquids. But in the quantum world, matter can organize itself in far stranger ways. They can host exotic particles and remarkable behaviors that defy everyday experience. One of the most famous examples is superconductivity, in which electric current flows without any resistance. Another is the fractional quantum Hall effect, where electrons split into particles carrying only a fraction of the electron’s charge. In a new study in Newton, researchers show how these two phenomena can arise at the same time.
Until recently, superconductivity and the fractional quantum Hall effect seemed to belong to completely different worlds. Superconductivity usually appears in metals cooled close to absolute zero, while the fractional quantum Hall effect arises in strong magnetic fields. Yet, to scientists’ surprise, both have now been observed side by side in the same material.
A new theoretical study by scientists from Harvard and the Technical University of Munich offers a striking explanation: superconductivity can emerge directly from the exotic particles of the fractional quantum Hall effect, known as anyons. Anyons do not behave like the familiar building blocks of matter—fermions (such as electrons) or bosons (such as photons). Instead, they follow their own set of quantum rules and can carry fractional electric charge.
The research shows that, under the right conditions, pairs of these anyons can bind together and allow electrical current to flow without resistance, creating a new route to superconductivity. The key, the authors find, is that this happens when the system is near a transition between two unusual quantum phases: a fractional quantum Hall phase and a newly proposed state where anyons arrange themselves in a regular pattern.
“This work uncovers a new mechanism for superconductivity rooted in fractionalized quantum matter,” Fabian Pichler, a graduate student at the Technical University of Munich and co-lead author, explains. “It links two of the most fascinating discoveries in physics and suggests new ways to engineer superconductivity in two-dimensional materials.”
By revealing how superconductivity can arise from the very particles responsible for fractionalization, the study opens a window into designing entirely new quantum phases—beyond those found in nature so far.
Further information
The research was supported, in part, by the Simons Investigator award, the Simons Collaboration on Ultra-Quantum Matter, which is a grant from the Simons Foundation (651440, A.V.), the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy–EXC–2111–390814868, TRR 360 – 492547816 and DFG grants No. KN1254/1-2, KN1254/2-1, the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 851161), the European Union (grant agreement No 101169765), as well as the Munich Quantum Valley, which is supported by the Bavarian state government with funds from the Hightech Agenda Bayern Plus.
Publication
F. Pichler, C. Kuhlenkamp, M. Knap, A. Vishwanath. Microscopic Mechanism of Anyon Superconductivity Emerging from Fractional Chern Insulators.
Newton. https://doi.org/10.1016/j.newton.2025.100340
Scientific contact
Michael Knap
Professor for Collective Quantum Dynamics
Technical University of Munich
TUM School of Natural Sciences
James-Franck-Str. 1, 85748 Garching, Germany
Tel. +49 89 289 53777
michael.knap(at)ph.tum.de
Ashvin Vishwanath
George Vasmer Leverett Professor of Physics
Harvard University
https://www.physics.harvard.edu/people/facpages/vishwanath
ashvin_vishwanath(at)fas.harvard.edu
Press contact