Patent ID: 8049943

Claim:
A quantum bit computation method comprising: preparing an optical resonator with a resonance frequency; preparing a plurality of first physical systems contained in the optical resonator and including at least three energy states and two energy states, the three energy states being represented by | 0 >, | 1 > and | 3 >, the two energy states being represented by | 2 > and | 4 >, energies of | 2 > and | 4 > being higher than energies of | 0 >, | 1 > and | 3 >, a transition frequency between | 3 > and | 2 > being equal to the resonance frequency, | 0 > and | 1 > representing quantum bits; operating a two-quantum-bit gate on quantum bits of a first physical system and a second physical system contained in the first physical systems, using the optical resonator and first energy states of the first physical system and the second physical system which are other than | 0 > and | 1 >, second energy states of second physical systems except for the first physical system and the second physical system do not change; flipping quantum bits of the first physical systems after operating the two-quantum-bit gate; executing no operations by a time equal to a time for operating the two-quantum-bit gate, after flipping the quantum bits; and again flipping the quantum bits of the first physical systems after executing no operations.