Non-Invertible Interfaces in Symmetry-Enriched Critical Phases
Published:Dec 29, 2025 18:59
•1 min read
•ArXiv
Analysis
This paper explores the interfaces between gapless quantum phases, particularly those with internal symmetries. It argues that these interfaces, rather than boundaries, provide a more robust way to distinguish between different phases. The key finding is that interfaces between conformal field theories (CFTs) that differ in symmetry charge assignments must flow to non-invertible defects. This offers a new perspective on the interplay between topology and gapless phases, providing a physical indicator for symmetry-enriched criticality.
Key Takeaways
- •Interfaces, not boundaries, are key to distinguishing gapless phases.
- •Non-invertible defects arise at interfaces between CFTs with different symmetry charge assignments.
- •The work provides a new handle on the interplay between topology and gapless phases.
- •Results have implications for higher-dimensional examples, including symmetry-enriched variants of the 2+1d Ising CFT.
Reference
“Whenever two 1+1d conformal field theories (CFTs) differ in symmetry charge assignments of local operators or twisted sectors, any symmetry-preserving spatial interface between the theories must flow to a non-invertible defect.”