Solution

ID: past-exam-of-the-groups-and-representations-course-of-the-university-of-oxford/2018/3/d/solution

The Clifford algebra condition for signature is
Each Pauli matrix squares to , and distinct Pauli matrices anticommute. Therefore the given choice obeys
These check all diagonal and off-diagonal anticommutators, proving
Thus they are viable three-dimensional gamma matrices. Their Hermitian adjoints satisfy and for . Two components are minimal: one-dimensional nonzero scalar matrices cannot anticommute while all having nonzero squares.

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