A method for performing a single-qubit gate on an arbitrary quantum state.
An ancillary qubit is set to an initial state |I>. The data qubit is
coupled to an ancillary qubit. The state of the ancillary qubit is
measured, and the data qubit and the ancillary qubit are coupled for a
first period of time. A method for applying a single-qubit gate to an
arbitrary quantum state. A state of a first and second ancillary qubit
are set to an entangled initial state |I>. A state of a data qubit and
the first ancillary qubit are measured thereby potentially performing a
single qubit operation on the arbitrary quantum state. A first result is
determined. The first result indicates whether the single qubit operation
applied the single qubit gate to the arbitrary quantum state.