System and method for controlling superconducting qubits using single flux quantum logic
A system and method for controlling superconducting qubits is provided. In some aspects the method includes assembling, using a controller of a quantum computing system, a pulse subsequence that comprises pairs of voltage pulses timed symmetrically with respect to a period corresponding to a qubit frequency of a superconducting qubit in the quantum computing system. The method also includes generating, using the controller, a pulse sequence using a repetition of a pulse subsequence. The method further includes controlling the superconducting qubit by applying the pulse sequence to the superconducting qubit using a single flux quantum (“SFQ”) driver coupled thereto.
1. A quantum computing system comprising:
a qubit architecture comprising a superconducting qubit described by a qubit frequency; and
a single flux quantum (“SFQ”) driver coupled to the superconducting qubit,
wherein the SFQ driver is configured to provide a pulse sequence to control the superconducting qubit, the pulse sequence being generated using a repetition of a pulse subsequence that comprises pairs of voltage pulses timed symmetrically with respect to a period corresponding to the qubit frequency.
2. The system of claim 1 , wherein the superconducting qubit comprises a transmon qubit.
3. The system of claim 1 , wherein the at least one transmon qubit is capacitively coupled to the SFQ driver.
4. The system of claim 1 , wherein the system further comprises a controller configured to direct the SFQ driver to provide the pulse sequence to the superconducting qubit in the qubit architecture.
5. The system of claim 4 , wherein the controller is further configured to assemble the pulse subsequence using approximately between 30 and 60 classical bits.
6. The system of claim 4 , wherein the controller is further configured to assemble the pulse subsequence to perform a gate on the superconducting qubit.
7. The system of claim 4 , wherein the controller is further configured to optimize the pulse subsequence to minimize leakage from a computational subspace of the superconducting qubit.
8. The system of claim 4 , wherein the controller is further configured to control multiple qubits in the qubit architecture using the SFQ driver by assembling the pulse subsequence to satisfy a frequency matching condition.
9. A method for controlling superconducting qubits, the method comprising:
assembling, using a controller of a quantum computing system, a pulse subsequence that comprises pairs of voltage pulses timed symmetrically with respect to a period corresponding to a qubit frequency of a superconducting qubit in the quantum computing system;
generating, using the controller, a pulse sequence using a repetition of a pulse subsequence; and
controlling the superconducting qubit by applying the pulse sequence to the superconducting qubit using a single flux quantum (“SFQ”) driver coupled thereto.
10. The method of claim 9 , wherein the method further comprises controlling at least one transmon qubit that is capacitively coupled to the SFQ driver.
11. The method of claim 9 , wherein the method further comprises assembling the pulse subsequence using approximately between 30 and 60 classical bits.
12. The method of claim 9 , wherein the method further comprises assembling the pulse subsequence to perform a gate on the superconducting qubit.
13. The method of claim 9 , wherein the method further comprises optimizing the pulse subsequence to minimize leakage from a computational subspace of the superconducting qubit.
14. The method of claim 9 , wherein the method further comprises controlling multiple qubits in the qubit architecture of the quantum computing system using an SFQ driver coupled thereto.
15. The method of claim 14 , wherein the method further comprises tuning the qubit frequency for selected qubits such that a gate time associated with the pulse sequence corresponds to both an integer number of SFQ clock cycles and an integer number of qubit cycles.