At a Glance
- Researchers propose a framework utilizing advanced mathematics to enhance topological quantum computers, which protect information by encoding it in exotic particles known as anyons.
- Conventional Ising anyons are promising but not powerful enough on their own for universal quantum computation because their braiding operations are limited to a specific set of tasks.
- The team shows that adding just one new stationary particle, which they call a “neglecton,” elevates the Ising anyon system to full universal computational power.
- This “neglecton” emerges from a mathematical framework that retains objects previously discarded as useless, turning what was considered mathematical garbage into a vital computational resource.
- The discovery creates a clear target for experimentalists to unlock the full power of existing quantum systems if this new stationary anyon can be physically realized.
Scientists have discovered a path to upgrade one of the most promising platforms for fault-tolerant quantum computing, a breakthrough that hinges on a particle previously dismissed as mathematical noise. Quantum computers promise to solve problems impossible for current supercomputers, but the quantum bits, or “qubits,” they use are incredibly fragile. A leading solution is topological quantum computing, which encodes information in the braiding of exotic particles called anyons, making the data highly resistant to environmental errors. However, a top candidate, the Ising anyon, has a significant drawback: on its own, its braiding operations are not powerful enough for universal quantum computation.
In a study published in Nature Communications, a team of researchers led by the University of Southern California has shown how to overcome this limitation. By expanding the standard mathematical theories used to describe anyons, they revealed a new type of particle that provides the exact missing ingredient. The team demonstrated that adding just one of these new particles—which they have dubbed “neglectons”—to a system of Ising anyons is enough to unlock the full power of universal quantum computation through braiding alone. The neglecton itself remains stationary while the other anyons are woven around it to perform calculations.
The breakthrough came from exploring non-semisimple topological quantum field theories, a more complex mathematical framework than what is typically used. Standard models simplify the math by eliminating particular objects, effectively treating them as irrelevant. “But those discarded objects turn out to be the missing piece,” said Aaron Lauda, the study’s senior author and a professor at the USC Dornsife College of Letters, Arts and Sciences, in a university press release. “It’s like finding treasure in what everyone else thought was mathematical garbage.” This new framework retains these overlooked components, which naturally give rise to the neglecton.
While the advanced mathematics introduced some theoretical instabilities, the researchers devised a clever way to quarantine them. “Think of it like designing a quantum computer in a house with some unstable rooms,” Lauda explained. “You ensure all of your computing happens in the structurally sound areas while keeping the problematic spaces off-limits.” This work provides a clear target for experimental physicists. If they can find a way to create and host this stationary neglecton in a real material, it could transform existing platforms into fully functional, universal quantum computers.
References
- Iulianelli, F., Kim, S., Sussan, J., & Lauda, A. D. (2025). Universal quantum computation using Ising anyons from a non-semisimple topological quantum field theory. Nature Communications, 16(1), 6408. https://doi.org/10.1038/s41467-025-61342-8
- University of Southern California. (2025, August 5). Discarded particles dubbed ‘neglectons’ may unlock universal quantum computing. Phys.Org; University of Southern California. https://phys.org/news/2025-08-discarded-particles-dubbed-neglectons-universal.html
