Fast Charge Readout with an Ultra-Low-Noise SQUID Amplifier: Published in Journal of Applied Physics!


Spin quantum computers will require fast and accurate qubit read out. Here, we use reflectometry with a SQUID preamplifier at 200 MHz to obtain record capacitance sensitivity of 0.07 aF/sqrt(Hz). Integrating for 1 μs, a signal-to-noise ratio of about 38 is obtained, allowing us to acquire a 100 x 100 pixel double-dot charge stability diagram in only 20 ms (see Figure). Schupp, Vigneau et al., Journal of Applied Physics 127, 244503 (Jun 29, 2020).