Computer-assisted quantum dot tuning for quantum computation and simulation

Much progress was made using electrostatically defined semiconductor quantum dots as the basis for quantum computation and simulation. In these experiments, a desired potential landscape is formed in a two-dimensional electron gas by individually adjusting the voltages applied to multiple gate electrodes. As a result, the filling of each dot, its electrochemical potential and its tunnel coupling to neighbouring dots or to reservoirs are precisely controlled. Next, control signals for initialization, manipulation and read-out of individual charges and spins are calibrated. Despite this encouraging progress, the field could move faster if tuning and calibration tasks were more extensively assisted or taken over by computer automation. We started work several years ago on automating the initial tuning of coupled quantum dots to the few-electron regime [1] and the subsequent setting of the interdot tunnel coupling [2]. In parallel, we also invested in efficient (fast) measurement methods and the use of virtual gates [3] that allow real-time manual tuning and speed up computer-assisted tuning as well. Currently, our focus is on automating repetitive tasks such as calibration or compensation for background charge switches. I will present our past and present tuning efforts and summarize recent physics experiments on 2x2 and 8x1 quantum dot arrays that are enabled by these tuning methods.
[1] Baart et al, APL 108, 213104 (2016)
[2] C.J. van Diepen et al, APL 113, 033101 (2018)
[3] T. Hensgens et al, Nature 548, 70 (2017)