Patent ID: 7447719

Claim:
A quantum computer comprising: an (N+1) number of physical systems each of which has five energy levels |0>, |1>, |2>, |3>, and |4>, a qubit being expressed by two levels, |0> and |1>, of the three lower levels, transitions between each of the three lower levels |0>, |1>, and |2> and each of the two upper levels |3> and |4> being optically allowed, and a transition frequency between two levels |2> and |3> in each of the physical systems being equal to one another; an optical cavity which has the physical systems arranged therein and is resonant with the transition frequency between the two levels |2> and |3>; frequency and amplitude modulators which generate light pulses resonant with the transitions between each of the three lower levels |0>, |1>, and |2> and each of the two upper levels |3> and |4> in each of the physical systems; phase modulators which control the phases of the light pulses; and a control unit which operates the frequency and amplitude modulators and the phase modulators in synchronization with one another.