Amplitude, frequency, and phase modulated simultaneous entangling gates for trapped-ion quantum computers

1. A method of performing a computation using a quantum computer, comprising:

generating a plurality of laser pulses used to be individually applied to each of a plurality of trapped ions that are aligned in a first direction, each of the trapped ions having two frequency-separated states defining a qubit, wherein generating the plurality of laser pulses comprises:

adjusting an amplitude value and a detuning frequency value of each of the plurality of laser pulses based on values of pair-wise entanglement interaction in the plurality of trapped ions that is to be caused by the plurality of laser pulses; and

applying the generated plurality of laser pulses to the plurality of trapped ions to perform simultaneous pair-wise entangling gate operations on the plurality of trapped ions.

2. The method according to claim 1 , wherein the amplitude value and the detuning frequency value of each of the plurality of laser pulses are adjusted such that the plurality of laser pulses cause pair-wise entanglement interaction in a first plurality of pairs of trapped ions among the plurality of trapped ions and do not cause pair-wise entanglement interaction in a second plurality of pairs of trapped ions among the plurality of trapped ions.

3. The method according to claim 2 , wherein the pair-wise entanglement interaction in the first plurality of pairs of trapped ions among the plurality of trapped ions has a value between zero and π/2.

4. The method according to claim 2 , wherein generating the plurality of laser pulses further comprises:

adjusting the amplitude value and the detuning frequency value of each of the plurality of laser pulses based on values of phase space trajectories of the plurality of trapped ions in a second direction that is perpendicular to the first direction that are to be caused by the plurality of laser pulses.

5. The method according to claim 4 , wherein

the amplitude value and the detuning frequency value of each of the plurality of laser pulses are adjusted further based on power provided to the plurality of trapped ions by the plurality of laser pulses.

6. The method according to claim 1 , wherein adjusting the amplitude value and the detuning frequency value of each of the plurality of laser pulses comprises dividing a gate duration value of the plurality of laser pulses into a plurality of time segments.

7. The method according to claim 1 , further comprising:

executing, by a processor in a digital computer, a software program that is stored in non-volatile memory of the digital computer, wherein the executed software program requires at least one computation to be performed, and performing the at least one computation comprises:

selecting, by the processor in the digital computer, a quantum algorithm to be implemented on the plurality of trapped ions;

compiling the selected quantum algorithm into a series of universal logic gates;

translating the series of universal logic gates into a series of simultaneous pair-wise entangling gate operations to apply on the plurality of trapped ions;

measuring population of qubit states of the plurality of trapped ions; and

processing quantum information corresponding to the qubit states of the plurality of trapped ions by the processor of the digital computer based on the measured population of the qubit states; and

generating a solution to the selected quantum algorithm based on the processed results of the quantum computations.

8. A non-transitory computer-readable medium including computer program instructions, which when executed by a processor, cause the processor to:

generate a plurality of laser pulses used to be individually applied to each of a plurality of trapped ions that are aligned in a first direction, each of the trapped ions having two frequency-separated states defining a qubit, wherein generating the plurality of laser pulses comprises:

adjusting an amplitude value and a detuning frequency value of each of the plurality of laser pulses based on values of pair-wise entanglement interaction in the plurality of trapped ions that is to be caused by the plurality of laser pulses; and

apply the generated plurality of laser pulses to the plurality of trapped ions to perform simultaneous pair-wise entangling gate operations on the plurality of trapped ions.

9. The non-transitory computer-readable medium according to claim 8 , wherein the amplitude value and the detuning frequency value of each of the plurality of laser pulses are adjusted such that the plurality of laser pulses cause pair-wise entanglement interaction in a first plurality of pairs of trapped ions among the plurality of trapped ions and do not cause pair-wise entanglement interaction in a second plurality of pairs of trapped ions among the plurality of trapped ions.

10. The non-transitory computer-readable medium according to claim 9 , wherein the pair-wise entanglement interaction in the first plurality of pairs of trapped ions among the plurality of trapped ions has a value between zero and π/2.

11. The non-transitory computer-readable medium according to claim 9 , wherein generating the plurality of laser pulses further comprises:

adjusting the amplitude value and the detuning frequency value of each of the plurality of laser pulses based on values of phase space trajectories of the plurality of trapped ions in a second direction that is perpendicular to the first direction that are to be caused by the plurality of laser pulses.

12. The non-transitory computer-readable medium according to claim 11 , wherein

the amplitude value and the detuning frequency value of each of the plurality of laser pulses are adjusted further based on power provided to the plurality of trapped ions by the plurality of laser pulses.

13. The non-transitory computer-readable medium according to claim 9 , wherein adjusting the amplitude value and the detuning frequency value of each of the plurality of laser pulses comprises dividing a gate duration value of the plurality of laser pulses into a plurality of time segments.

14. A quantum computing system, comprising:

a plurality of trapped ions that are aligned in a first direction, each of the trapped ions having two hyperfine states defining a qubit; and

a controller comprising non-volatile memory having a number of instructions stored therein which, when executed by a processor, causes the quantum computing system to perform operations comprising:

generating a plurality of laser pulses used to be individually applied to each of the plurality of trapped ions, wherein generating the plurality of laser pulses comprises:

adjusting an amplitude value and a detuning frequency value of each of the plurality of laser pulses based on values of pair-wise entanglement interaction in the plurality of trapped ions that is to be caused by the plurality of laser pulses; and

applying the generated plurality of laser pulses to the plurality of trapped ions to perform simultaneous pair-wise entangling gate operations on the plurality of trapped ions.

15. The quantum computing system according to claim 14 , wherein

each of the trapped ions is 171 Yb + having 2 S 1/2 hyperfine states.

16. The quantum computing system according to claim 14 , wherein the amplitude value and the detuning frequency value of each of the plurality of laser pulses are adjusted such that the plurality of laser pulses cause pair-wise entanglement interaction in a first plurality of pairs of trapped ions among the plurality of trapped ions and do not cause pair-wise entanglement interaction in a second plurality of pairs of trapped ions among the plurality of trapped ions.

17. The quantum computing system according to claim 16 , wherein the pair-wise entanglement interaction in the first plurality of pairs of trapped ions among the plurality of trapped ions has a value between zero and π/2.

18. The quantum computing system according to claim 16 , wherein generating the plurality of laser pulses further comprises:

adjusting the amplitude value and the detuning frequency value of each of the plurality of laser pulses based on values of phase space trajectories of the plurality of trapped ions in a second direction that is perpendicular to the first direction that are to be caused by the plurality of laser pulses.

19. The quantum computing system according to claim 18 , wherein

the amplitude value and the detuning frequency value of each of the plurality of laser pulses are adjusted further based on power provided to the plurality of trapped ions by the plurality of laser pulses.

20. The quantum computing system according to claim 14 , wherein adjusting the amplitude value and the detuning frequency value of each of the plurality of laser pulses comprises dividing a gate duration value of the plurality of laser pulses into a plurality of time segments.