Hybrid Quantum Systems by combining Superconducting Electromagnetic Circuits with Quantum Materials

A thin supeconducting resonator used as an inductive probe of the superfluid density.

The field of superconducting quantum circuits (SQC) [1] is rapidly evolving and is a leading candidate for the implementation of quantum hardware. The main building blocks of SQC are fabricated electromagnetic circuit elements as opposed to natural atoms, and thus the properties of these ’artificial atoms’ can be tuned by changing the geometry and position of circuit elements. While typical circuits are made from conventional superconductors (e.g. aluminium),there has been recent exiciting progress from a growing new class of unconventional superconductors, including high-temperature superconductors and the more exotic topological superconductors[2]. These materials exhibit unique collective quantum phenomena, but their internal structure is still largely unknown. By combining such materials as part of SQC, we can utilize the SQC as a quantum sensor which is highly sensitive to the superfluid density in the material, allowing us to study its pairing mechanism and gain insight into its internal structure. Additionally, such a circuit can be seen as a novel artificial atom in its own right, with the unconventional superconductor contributing its inherent nonlinarity [3] or internal excitations to create quantum systems which are inaccesible using conventional circuits.
In this PhD project, you will fabricate, measure and analyze hybrid microwave superconducting circuits which include unconventional superconductors in their design. This project combines expertise in quantum information and condensed-matter physics, pushing the boundaries of our understanding of unconventional superconductivity and creating new exotic quantum circuits.

References

[1] U. Vool and M. Devoret
Introduction to quantum electromagnetic circuits
International Journal of Circuit Theory and Applications 45, 897 (2017).
[2] A.P. Mackenzie and Y. Maeno
The superconductivity of Sr2RuO4 and the physics of spin-triplet pairing
Rev. Mod. Phys. 75, 657 (2003)
[3]  P. Winkel, K. Borisov, L. Grünhaupt, D. Rieger, M. Spiecker, F. Valenti, A. V. Ustinov, W. Wernsdorfer, and I. M. Pop
Implementation of a Transmon Qubit Using Superconducting Granular Aluminum
Phys. Rev. X 10, 031032 (2020)

Other Interesting Articles

Go to Editor View