Mitigating Defect Modes in Josephson-Junction-Based Superconducting Qubits

Abstract

Superconducting qubits are a leading platform for quantum computing, yet their coherence is often limited by interactions with two-level systems (TLS), particularly within Josephson-junction-based architectures. This work investigates strategies to mitigate the impact of TLS-induced decoherence by introducing on-chip electric field control. By leveraging precisely positioned electrodes, localized fields can be applied to systematically tune TLS dynamics, leading to measurable improvements in qubit relaxation times. However, the introduction of such control mechanisms also presents new challenges, as additional decoherence channels may arise. To counteract these effects, this study incorporates 3D low-pass filtering techniques to suppress high-frequency noise while preserving TLS tunability. The combined approach offers a pathway toward enhancing superconducting qubit performance and provides valuable insights into the interplay between quantum coherence and material-induced defect states.

Project Details

• Title: Mitigating Defect Modes in Josephson-Junction-Based Superconducting Qubits
• Supervisor: Jean-Claude Besse
• Category: Quantum Computing, Superconducting Qubits
• Location: ETH Zurich, Quantum Device Lab
• Project Date: February 2025

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