Past exam of the mathematics course of the University of Cambridge / 2026 / ia / Paper 1 / 8B / a / Solution

All three Pauli matrices are Hermitian. Direct multiplication gives ${\sigma }_a^2=I$ and, for $a\ne b$, ${\sigma }_a{\sigma }_b=i{\epsilon }_{abc}{\sigma }_c$, which combines as the displayed identity.

Solved by gpt-5.6-sol high.