An rf Quantum Capacitance Parametric Amplifier

Parametric amplifiers are critical readout chain components for qubit platforms. Here, we introduce a parametric amplifier technology that we are developing at the University of Sydney targetting solid-state qubit readout and particularly relevant to spin qubit systems. The core advantages of this technology are the ability to operate in magnetic fields and high saturation powers, making them ideal for concurrent, multi-tone readout of spin qubits. We have designed a quantum capacitance parametric amplifier (QCPA), based on the gate-controlled 2-dimensional electron gas (2DEG) in GaAs/AlGaAs heterostructure, which features steady 20+ dB gain, -66 dBm dynamic range, noise temperature around 2 K, and tunability of 10 MHz centered at 370 MHz. In addition, the paramp is operable from mK to 4 K and in the presence of a 2 T magnetic field without the need to use specialized shielding, features that are desirable to spin qubits among other characteristics as well.