Exploring Nonlinear Parametric Processes for Superconducting Quantum Applications

Superconducting circuit technologies are at the forefront of quantum research, offering promising pathways for advancements in quantum computing, sensing, and communication. These devices typically operate at extremely low power levels, often at the scale of just a few photons. Such low-power operation introduces several challenges, particularly concerning signal amplification and protection from noise. Currently, commercially available solutions—including low-noise High Electron Mobility Transistor (HEMT) amplifiers, traveling-wave parametric amplifiers (TWPA) and microwave circulators/isolators operating in the GHz frequency range— together have enabled single-shot readout of hundreds of qubits in state-of-the-art implementations. However, as the field advances toward quantum-error correction, the number of physical qubits required is expected to grow into the thousands or even millions. The increase in qubit count presents significant bottlenecks for existing readout strategies, especially within the constraints of a typical dilution refrigerator setup, which provides a limited amount of experimental space and cooling power.

Building on recent developments in the field, solutions capable of overcoming some of these limitations are being developed in our group. This master’s thesis project will build on our current understanding and expand the focus by developing on-chip superconducting circuit solutions for readout components. The approach utilizes nonlinear parametric processes to engineer interactions between electromagnetic modes to achieve amplification and/or isolation. The student will use analytical modeling and circuit/layout simulations to evaluate, assess and propose an innovative architecture designed to overcome the scaling limitations inherent in current readout strategies.