Calculating Unknown Eigenvalues with a Quantum Algorithm

Understand

Quantum algorithms are able to solve particular problems exponentially faster than conventional algorithms, when implemented on a quantum computer.

• However, all demonstrations to date have required already knowing the answer to construct the algorithm.
• We have implemented the complete quantum phase estimation algorithm for a single qubit unitary in which the answer is calculated by the algorithm.
• We use a new approach to implementing the controlled-unitary operations that lie at the heart of the majority of quantum algorithms that is more efficient and does not require the eigenvalues of the unitary to be known.