Quantum computing device for Ising model, quantum parallel computing device for Ising model, and quantum computing method for Ising model

1. An Ising model quantum computation device comprising:

a parametric oscillator that parametrically oscillates a plurality of pseudo spin pulses, the plurality of pseudo spin pulses being in correspondence with a plurality of Ising model spins in a pseudo manner and having mutually an identical oscillation frequency;

a ring resonator in which the plurality of pseudo spin pulses circularly propagate;

a temporary pulse detector that temporarily measures phases of the plurality of pseudo spin pulses every time the plurality of pseudo spin pulses circularly propagate in the ring resonator to temporarily measure pseudo spins of the plurality of pseudo spin pulses;

an interaction computing circuit that temporarily computes sum of interaction between a pseudo spin of a certain pseudo spin pulse and a pseudo spin of all other pseudo spin pulses interacting with the pseudo spin of the certain pseudo spin pulse, based on a coupling coefficient of the Ising model related to the pseudo spin of the certain pseudo spin pulse and the pseudo spins of the other pseudo spin pulses having been temporarily measured by the temporary pulse detector;

a pulse injector that controls amplitudes and phases of light injected to the certain pseudo spin pulse to temporarily implement a magnitude and a sign of the sum of the interaction between the pseudo spin of the certain pseudo spin pulse and the pseudo spin of all the other pseudo spin pulses interacting with the pseudo spin of the certain pseudo spin pulse, the sum of the interaction having been temporarily computed by the interaction computing circuit; and

a pseudo pulse detector that measures the phases of the plurality of pseudo spin pulses after the plurality of pseudo spin pulses have arrived at a steady state in a process of repeating a feedback loop configured of the temporary pulse detector, the interaction computing circuit, and the pulse injector to measure the pseudo spins of the plurality of pseudo spin pulses.

2. The Ising model quantum computation device according to claim 1 , wherein

the interaction computing circuit temporarily computes the sum of interaction of three or more bodies between the pseudo spin of the certain pseudo spin pulse and the pseudo spin of all the other pseudo spin pulses interacting with the pseudo spin of the certain pseudo spin pulse, based on a coupling coefficient of three or more bodies of the Ising model related to the pseudo spin of the certain pseudo spin pulse and the pseudo spin of the other pseudo spin pulses having been temporarily measured by the temporary pulse detector, and

the pulse injector controls the amplitudes and the phases of light injected to the certain pseudo spin pulse to temporarily implement a magnitude and a sign of the sum of the interaction of three or more bodies between the pseudo spin of the certain pseudo spin pulse and the pseudo spin of all the other pseudo spin pulses interacting with the pseudo spin of the certain pseudo spin pulse, the sum of the interaction having been temporarily computed by the interaction computing circuit.

3. The Ising model quantum computation device according to claim 1 , wherein

the parametric oscillator parametrically oscillates a plurality of local oscillation pulses having an oscillation frequencies identical to the oscillation frequencies of the plurality of pseudo spin pulses, the plurality of local oscillation pulses pairing with the plurality of pseudo spin pulses one-on-one,

the ring resonator in which the plurality of local oscillation pulses circularly propagate,

the Ising model quantum computation device further includes a phase modulator that equalizes phases of the plurality of local oscillation pulses from a state including both positive phases and negative phases to a state including one of positive phases and negative phases,

the temporary pulse detector performs homodyne detection for a part of the plurality of pseudo spin pulses by using a part of the plurality of local oscillation pulses that pair with the plurality of pseudo spin pulses one-on-one,

the pulse injector injects local oscillation pulses that pair with a plurality of the certain pseudo spin pulses one-on-one and the part of which have the controlled amplitudes and phases, to the plurality of the certain pseudo spin pulses, and

the pseudo pulse detector performs homodyne detection for a part of the plurality of pseudo spin pulses by using a part of the plurality of local oscillation pulses that pair with the plurality of pseudo spin pulses one-on-one.

4. The Ising model quantum computation device according to claim 1 , further comprising:

a pulse generator that generates a local oscillation pulse having an angular frequency ω; and

a second harmonic generator that generates a pulse having an angular frequency 2ω by using the local oscillation pulse having the angular frequency ω, wherein

the parametric oscillator parametrically oscillates the plurality of pseudo spin pulses by using the pulse having the angular frequency 2ω,

the temporary pulse detector performs homodyne detection for a part of the plurality of pseudo spin pulses by using the local oscillation pulse having the angular frequency ω,

the pulse injector injects the local oscillation pulse having the angular frequency ω with a controlled amplitude and phase, to the certain pseudo spin pulse, and

the pseudo pulse detector performs homodyne detection for a part of the plurality of pseudo spin pulses by using the local oscillation pulse having the angular frequency ω.

5. The Ising model quantum computation device according to claim 1 , wherein

the pulse injector controls the amplitude of light injected to the certain pseudo spin pulse larger at an initial stage of a computation process and smaller at a terminal stage of the computation process.

6. The Ising model quantum computation device according to claim 1 , further comprising

a temporary amplitude detector that temporarily measures amplitudes of the plurality of pseudo spin pulses every time the plurality of pseudo spin pulses circularly propagate in the ring resonator, wherein

the parametric oscillator performs feedback control for amplitude of a pump pulse used for parametric oscillation such that the amplitudes of the plurality of pseudo spin pulses become equal based on the amplitudes of the plurality of pseudo spin pulses having been measured by the temporary amplitude detector.

7. An Ising model quantum parallel computation device comprising:

n-th Ising model quantum computation device according to claim 1 where n-th group (n is an integer equal to or more than one) of pseudo spin pulses in correspondence with n-th group of spins in a pseudo manner among the plurality of Ising model spins circularly propagate in the ring resonator; and

a temporary spin sharing circuit that shares information of pseudo spins of the n-th group of pseudo spin pulses among the Ising model quantum computation devices included in parallel, the n-th group of pseudo spin pulses having been temporarily measured by the temporary pulse detector in the n-th Ising model quantum computation device.

8. An Ising model quantum computation method comprising:

parametrically oscillating a plurality of pseudo spin pulses, the plurality of pseudo spin pulses being in correspondence with a plurality of Ising model spins in a pseudo manner and having mutually an identical oscillation frequency;

temporarily measuring phases of the plurality of pseudo spin pulses every time the plurality of pseudo spin pulses circularly propagate in a ring resonator to temporarily measure pseudo spins of the plurality of pseudo spin pulses;

temporarily computing sum of interaction between a pseudo spin of a certain pseudo spin pulse and a pseudo spin of all other pseudo spin pulses interacting with the pseudo spin of the certain pseudo spin pulse, based on a coupling coefficient of the Ising model related to the pseudo spin of the certain pseudo spin pulse and the pseudo spins of the other pseudo spin pulses having been temporarily measured every time the plurality of pseudo spin pulses circularly propagate in the ring resonator;

controlling an amplitude and a phase of light injected to the certain pseudo spin pulse every time the plurality of pseudo spin pulses circularly propagate in the ring resonator to temporarily implement a magnitude and a sign of the sum of the interaction between the pseudo spin of the certain pseudo spin pulse and the pseudo spins of all the other pseudo spin pulses interacting with the pseudo spin of the certain pseudo spin pulse, the sum of the interaction having been temporarily computed;

parametrically amplifying the plurality of pseudo spin pulses every time the plurality of pseudo spin pulses circularly propagate in the ring resonator; and

measuring the phases of the plurality of pseudo spin pulses after the plurality of pseudo spin pulses have arrived at a steady state in a process of repeating a feedback loop including temporary spin measuring, interaction implementing, and parametric amplifying in this order to measure the pseudo spins of the plurality of pseudo spin pulses.

9. An Ising model quantum computation method comprising:

parametrically oscillating a plurality of pseudo spin pulses, the plurality of pseudo spin pulses being in correspondence with a plurality of Ising model spins in a pseudo manner and having mutually an identical oscillation frequency;

temporarily measuring phases of the plurality of pseudo spin pulses every time the plurality of pseudo spin pulses circularly propagate in a ring resonator to temporarily measure pseudo spins of the plurality of pseudo spin pulses;

temporarily computing sum of interaction between a pseudo spin of a certain pseudo spin pulse and a pseudo spin of all other pseudo spin pulses interacting with the pseudo spin of the certain pseudo spin pulse, based on a coupling coefficient of the Ising model related to the pseudo spin of the certain pseudo spin pulse and the pseudo spins of the other pseudo spin pulses having been temporarily measured every time the plurality of pseudo spin pulses circularly propagate in the ring resonator;

parametrically amplifying the plurality of pseudo spin pulses every time the plurality of pseudo spin pulses circularly propagate in the ring resonator;

controlling an amplitude and a phase of light injected to the certain pseudo spin pulse every time the plurality of pseudo spin pulses circularly propagate in the ring resonator to temporarily implement a magnitude and a sign of the sum of the interaction between the pseudo spin of the certain pseudo spin pulse and the pseudo spins of all the other pseudo spin pulses interacting with the pseudo spin of the certain pseudo spin pulse, the sum of the interaction having been temporarily computed; and

measuring the phases of the plurality of pseudo spin pulses after the plurality of pseudo spin pulses have arrived at a steady state in a process of repeating a feedback loop including temporary spin measuring, parametric amplifying, and interaction implementing in this order to measure the pseudo spins of the plurality of pseudo spin pulses.

10. The Ising model quantum computation device according to claim 2 , wherein

the parametric oscillator parametrically oscillates a plurality of local oscillation pulses having an oscillation frequencies identical to the oscillation frequencies of the plurality of pseudo spin pulses, the plurality of local oscillation pulses pairing with the plurality of pseudo spin pulses one-on-one,

the ring resonator in which the plurality of local oscillation pulses circularly propagate,

the Ising model quantum computation device further includes a phase modulator that equalizes phases of the plurality of local oscillation pulses from a state including both positive phases and negative phases to a state including one of positive phases and negative phases,

the temporary pulse detector performs homodyne detection for a part of the plurality of pseudo spin pulses by using a part of the plurality of local oscillation pulses that pair with the plurality of pseudo spin pulses one-on-one,

the pulse injector injects local oscillation pulses that pair with the certain pseudo spin pulses one-on-one and the part of which have the controlled amplitudes and phases, to the certain pseudo spin pulses, and

the pseudo pulse detector performs homodyne detection for a part of the plurality of pseudo spin pulses by using a part of the plurality of local oscillation pulses that pair with the plurality of pseudo spin pulses one-on-one.

11. The Ising model quantum computation device according to claim 2 , further comprising:

a pulse generator that generates a local oscillation pulse having an angular frequency ω; and

a second harmonic generator that generates a pulse having an angular frequency 2ω by using the local oscillation pulse having the angular frequency ω, wherein

the parametric oscillator parametrically oscillates the plurality of pseudo spin pulses by using the pulse having the angular frequency 2ω,

the temporary pulse detector performs homodyne detection for a part of the plurality of pseudo spin pulses by using the local oscillation pulse having the angular frequency ω,

the pulse injector injects the local oscillation pulse having the angular frequency ω with a controlled amplitude and phase, to the certain pseudo spin pulse, and

the pseudo pulse detector performs homodyne detection for a part of the plurality of pseudo spin pulses by using the local oscillation pulse having the angular frequency ω.

12. The Ising model quantum computation device according to claim 2 , wherein

the pulse injector controls the amplitude of light injected to the certain pseudo spin pulse larger at an initial stage of a computation process and smaller at a terminal stage of the computation process.

13. The Ising model quantum computation device according to claim 2 , further comprising

a temporary amplitude detector that temporarily measures amplitudes of the plurality of pseudo spin pulses every time the plurality of pseudo spin pulses circularly propagate in the ring resonator, wherein

the parametric oscillator performs feedback control for amplitude of a pump pulse used for parametric oscillation such that the amplitudes of the plurality of pseudo spin pulses become equal based on the amplitudes of the plurality of pseudo spin pulses having been measured by the temporary amplitude detector.

14. An Ising model quantum parallel computation device comprising:

n-th Ising model quantum computation device according to claim 2 where n-th group (n is an integer equal to or more than one) of pseudo spin pulses in correspondence with n-th group of spins in a pseudo manner among the plurality of Ising model spins circularly propagate in the ring resonator; and

a temporary spin sharing circuit that shares information of pseudo spins of the n-th group of pseudo spin pulses among the Ising model quantum computation devices included in parallel, the n-th group of pseudo spin pulses having been temporarily measured by the temporary pulse detector in the n-th Ising model quantum computation device.

15. The Ising model quantum computation device according to claim 3 , wherein

the pulse injector controls the amplitude of light injected to the certain pseudo spin pulse larger at an initial stage of a computation process and smaller at a terminal stage of the computation process.

16. The Ising model quantum computation device according to claim 3 , further comprising

a temporary amplitude detector that temporarily measures amplitudes of the plurality of pseudo spin pulses every time the plurality of pseudo spin pulses circularly propagate in the ring resonator, wherein

the parametric oscillator performs feedback control for amplitude of a pump pulse used for parametric oscillation such that the amplitudes of the plurality of pseudo spin pulses become equal based on the amplitudes of the plurality of pseudo spin pulses having been measured by the temporary amplitude detector.

17. An Ising model quantum parallel computation device comprising:

n-th Ising model quantum computation device according to claim 3 where n-th group (n is an integer equal to or more than one) of pseudo spin pulses in correspondence with n-th group of spins in a pseudo manner among the plurality of Ising model spins circularly propagate in the ring resonator; and

a temporary spin sharing circuit that shares information of pseudo spins of the n-th group of pseudo spin pulses among the Ising model quantum computation devices included in parallel, the n-th group of pseudo spin pulses having been temporarily measured by the temporary pulse detector in the n-th Ising model quantum computation device.

18. The Ising model quantum computation device according to claim 4 , wherein

the pulse injector controls the amplitude of light injected to the certain pseudo spin pulse larger at an initial stage of a computation process and smaller at a terminal stage of the computation process.

19. The Ising model quantum computation device according to claim 4 , further comprising

a temporary amplitude detector that temporarily measures amplitudes of the plurality of pseudo spin pulses every time the plurality of pseudo spin pulses circularly propagate in the ring resonator, wherein

the parametric oscillator performs feedback control for amplitude of a pump pulse used for parametric oscillation such that the amplitudes of the plurality of pseudo spin pulses become equal based on the amplitudes of the plurality of pseudo spin pulses having been measured by the temporary amplitude detector.

20. An Ising model quantum parallel computation device comprising:

n-th Ising model quantum computation device according to claim 4 where n-th group (n is an integer equal to or more than one) of pseudo spin pulses in correspondence with n-th group of spins in a pseudo manner among the plurality of Ising model spins circularly propagate in the ring resonator; and

a temporary spin sharing circuit that shares information of pseudo spins of the n-th group of pseudo spin pulses among the Ising model quantum computation devices included in parallel, the n-th group of pseudo spin pulses having been temporarily measured by the temporary pulse detector in the n-th Ising model quantum computation device.