Carbon Nanotube Monolayer Josephson Junction Superconducting Qubit

Summary

The superconducting quantum computing architecture has seen rapid improvements over the last two decades. However, the coherence time of superconducting qubits is limited by unknown noise sources presumably existent at the interface between the insulator and the superconducting film. Carbon nanotubes (CNTs) are a promising material for use in Josephson-Junctions (JJs) given their unique properties, such as high electrical conductivity, pristine surface, inherent nanoscale dimension, and silicon-compatible processing. In this project, we are building gate-controlled JJs composed of CNT thin films (down-to-monolayer) positioned between two superconducting electrodes to act as a promising superconducting qubit for quantum computers. Aside from gate-controllability, this approach offers superb interface engineering capability, small integration footprint, and high-temperature operation. We expect the CNT film – JJ superconducting qubit will achieve superior performance relative to current state-of-the-art JJs and enable the development of scalable superconducting computation with extensions to arrays of CNT-JJs coupled to microwave and optical photon-waveguides.

Figure 1. Cooper pairs interacting with gate-controlled Jospehson-Junctions composed of CNT thin films