Quantum Control Stack for Spin Qubits
Control electronics plays a crucial role in harnessing the quantum computing potential within Germanium chips. Electric signals are used to manipulate physical on-chip properties, such as charge carrier density and adding energy to the system. In this way, control electronics enable the creation of quantum dot structures, the trapping of single spin-full charge carriers in them, the manipulation of the spin-state that stores the quantum information, and enable the readout scheme to measure the outcome of a computation.
The fidelity of such qubit control hinges on the excellence of the analog signals. Consequently, comprehending the diverse forms of noise that come with electric signals is of great importance. We approach the control electronic requirements from an experimental perspective, considering the range of experiments that the electronics must be capable of executing.
Finally, we touch upon the trends in control electronic development towards upscale quantum computing control stacks.
Prerequiste Knowledge
- Quantum dots
- Zeeman splitting
- Bloch sphere
- Decoherence
- Phase noise
Main takeaways
- Ultra low-noise and stable DC voltages/currents are required to keep system parameters constant during an experiment.
- Pulsed RF signals are used to manipulate system parameters during an experiment.
- Dedicated and integrated electronic control enables the advance of scalable quantum computing.
- The development from AWGs to sequencers made fast on-the-fly pulse generation possible, opening up new electronic capabilities and reducing overhead times.
- On-board data processing allows for fast feedback control on the timescale of your experiment, by bypassing the slow communication channel with the PC.
Further thinking
Cross talk can be mitigated by:
a. Establishing virtual gates in software based on the measured capacitance matrix
b. Increasing the physical gap between neighbouring gates
c. Ensuring no overlap of physical gate structures
d. Fast gate pulsing