Real-time feedback protocols for optimizing fault-tolerant two-qubit gate fidelities in a silicon spin system

Understand

Recently, several groups have demonstrated two-qubit gate fidelities in semiconductor spin qubit systems above 99%.

• Achieving this regime of fault-tolerant compatible high fidelities is nontrivial and requires exquisite stability and precise control over the different qubit parameters over an extended period of time.
• This can be done by efficiently calibrating qubit control parameters against different sources of micro- and macroscopic noise.
• Here, we present several single- and two-qubit parameter feedback protocols, optimised for and implemented in state-of-the-art fast FPGA hardware.