cirq.pow_pauli_combination

cirq.pow_pauli_combination(ai: Union[complex, float], ax: Union[complex, float], ay: Union[complex, float], az: Union[complex, float], exponent: int) → Tuple[Union[complex, float], Union[complex, float], Union[complex, float], Union[complex, float]][source]

Computes non-negative integer power of single-qubit Pauli combination.

Returns scalar coefficients bi, bx, by, bz such that

bi I + bx X + by Y + bz Z = (ai I + ax X + ay Y + az Z)^exponent
Correctness of the formulas below follows from the binomial expansion
and the fact that for any real or complex vector (ax, ay, az) and any
non-negative integer k:
[ax X + ay Y + az Z]^(2k) = (ax^2 + ay^2 + az^2)^k I