https://doi.org/10.1140/epjb/s10051-025-01061-7
Research - Condensed Matter
Quantum consistency from topological symmetry: resolving the single Weyl fermion anomaly
FAST Foundation, Destin, USA
a
andrei.patrascu.11@ucl.ac.uk
Received:
4
August
2025
Accepted:
25
September
2025
Published online:
27
October
2025
Quantum anomalies impose profound constraints on our fundamental descriptions of nature, traditionally forbidding the existence of isolated Weyl fermions due to gauge inconsistencies. Here, we introduce a novel quantisation method based on Becchi–Rouet–Stora–Tyutin (BRST) symmetry and cohomological field theory, explicitly demonstrating that a single Weyl fermion doublet under an SU(2) gauge symmetry can be consistently quantised without anomalies. This approach introduces auxiliary BRST-exact fields that shift the anomalous fermionic measure into a trivial cohomological class, explicitly removing the anomaly while leaving no residual physical degrees of freedom. By bridging topological field theory and quantum consistency, this method not only overturns long-standing theoretical constraints but also opens experimental pathways to detecting standalone Weyl fermions. Our results significantly broaden the landscape of quantum field theories and highlight a deep interplay between topology, anomalies, and quantum gauge invariance.
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© The Author(s), under exclusive licence to EDP Sciences, SIF and Springer-Verlag GmbH Germany, part of Springer Nature 2025
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
