Parametric Amplification in a CMOS Quantum Dot coupled to a Microwave Cavity

Parametric amplification through pumping a non-linear or variable reactive element of a resonator can approach quantum-limited noise performance. Josephson junction parametric amplifiers (JPAs) based on a non-linear inductance have been instrumental in enabling rapid, high fidelity readout of superconducting qubits and, recently, semiconductor quantum dots (QDs).

We analyse through a semi-classical model and demonstrate experimentally parametric amplification using the tuneable tunnelling capacitance of a QD-reservoir electron transition in a CMOS nanowire split-gate transistor embedded in a 1.8 GHz superconducting spiral inductor microwave cavity. Pumping through one gate the QD-reservoir detuning at twice the cavity resonant frequency, while probing the hybrid QD-cavity in reflectometry, we achieve phase-sensitive (de)amplification of the reflection coefficient by (-)+3dB (cf. zero pump amplitude). The performance here was limited by the Sisyphus dissipation in the QD; however, we identify a clear path towards achieving gains comparable to JPAs using only the same devices already present for dispersive gate-based readout.