Publication in Quantum Science and Technology: “Cross-talk in superconducting qubit lattices with tunable couplers—comparing transmon and fluxonium architectures”
On December 8th, Quantum Science and Technology published our work on Cross-talk analysis in superconducting qubit architectures: “Cross-talk in superconducting qubit lattices with tunable couplers—comparing transmon and fluxonium architectures”.
This work is a collaboration between Florian Lange, Lukas Heunisch, Holger Fehske, David DiVincenzo and Michael Hartmann.
We investigate cross-talk effects in an 8-qubit system arranged in a 4×2 grid, on which the qubits are coupled via tunable couplers. Using DMRG methods, we numerically analyse the system from the perspective of many-body localisation, providing insights into how cross-talk effects can emerge in realistic quantum processors. We calculate both Walsh coefficients and the inverse participation ratio, two key measures that quantify the system’s potential to dephase and the risk of delocalised states. Our work compares several state-of-the-art superconducting qubit platforms, including Transmon architectures coupled via direct capacitance, Transmon tunable couplers or C-shunt flux couplers, as well as fluxonium architectures coupled via Transmon tunable couplers, which have recently gained prominence. For a detailed analysis and an answer to the question of which larger-scale architecture is favourable from a cross-talk perspective, feel free to check out the full paper.