Characterizing Diagonal Unitary Covariant Superchannels
Published:Dec 30, 2025 18:08
•1 min read
•ArXiv
Analysis
This paper provides a complete characterization of diagonal unitary covariant (DU-covariant) superchannels, which are higher-order transformations that map quantum channels to themselves. This is significant because it offers a framework for analyzing symmetry-restricted higher-order quantum processes and potentially sheds light on open problems like the PPT$^2$ conjecture. The work unifies and extends existing families of covariant quantum channels, providing a practical tool for researchers.
Key Takeaways
- •Provides a complete characterization of DU-covariant superchannels.
- •Derives necessary and sufficient conditions for complete positivity and trace preservation.
- •Offers a canonical decomposition for DU-covariant superchannels.
- •Unifies and extends known families of covariant quantum channels.
- •Provides a practical toolbox for symmetry-restricted higher-order quantum processes.
- •Offers a setting for exploring open problems like the PPT$^2$ conjecture.
Reference
“Necessary and sufficient conditions for complete positivity and trace preservation are derived and the canonical decomposition describing DU-covariant superchannels is provided.”