A Cryogenic CMOS Current Integrator and Correlation Double Sampling Circuit for Spin Qubit Readout

In this paper, we propose a CMOS current comparison circuit operating at cryogenic temperature to readout spin quantum bit (qubit) states via a charge sensing scheme. A current integrator and correlation double sampling circuit are implemented in the proposed current comparator since precise current sensing is required to achieve readout the states of qubits. The measurement results indicate the feasibility that the reduced readout time by a factor of 1/100 and 100-times better current resolution with the readout fidelity of 99.9 % compared to the conventional readout systems are achieved. Additionally, the current and noise specifications for a charge sensor required to attain it are discussed. Furthermore, the proposed current comparator attains the best tradeoff among power, current resolution, and readout time, compared with the conventional cryogenic current readout circuits.