Fast Quantum and Classical Phase Estimation

摘要

A quantum phase estimator may include at least one phase gate, at least one controlled unitary gate, and at least one measurement device. The quantum phase estimator receives at least one ancillary qubit and a calculational state comprised of multiple qubits. The phase gate may apply random phases to the ancillary qubit, which is used as a control to the controlled unitary gate. The controlled unitary gate applies a second random phase to the calculational state. The measurement device may measure a state of the ancillary qubit from which a phase of the calculational state may be determined.

主权项

1. A method of performing a quantum calculation, comprising:
applying a first random phase factor (e2πiθ) to an ancillary qubit; applying a second random phase factor (e2πiMφ) to a calculational state comprised of multiple qubits; measuring a state of the ancillary qubit to obtain phase information related to the second random phase factor; and calculating a phase (α) of a phase factor (e2πiα) for the calculational state based at least in part on the measured state of the ancillary qubit.