Extended Data Fig. 2: Experimental set-up for the two-qubit gate in a millikelvin dilution refrigerator.
From: A two-qubit gate between phosphorus donor electrons in silicon
The schematic shows the electrical connections from the device to the control computer at the different temperature stages of the dilution refrigerator from the top to bottom. An STM image of the device attached to the cold finger of the refrigerator at 50 mK is shown in the lower orange pane. The RF-reflectormetry circuit attached to the device employs a variable attenuator (‘Var. Atten.’) to control the power coupled through a directional coupler (‘Dir. Cplr.’) and sent to the source contact of the SET (red lines). The blue line is for d.c. current/voltage measurements of the SET. The slow signals (black components) and fast signals (green components) are combined using bias tees at 50 mK before being sent to the left and right gate electrodes.
