Superconducting qubit based on twisted cuprate van der Waals heterostructures

TL;DR

This paper proposes a new superconducting qubit called flowermon, based on twisted cuprate van der Waals heterostructures, which leverages the unique properties of atomically sharp interfaces and d-wave superconductivity for enhanced coherence.

Contribution

It introduces a novel qubit design utilizing twisted cuprate heterostructures with inherent protection against noise, advancing high-coherence superconducting quantum devices.

Findings

Proposes the flowermon qubit based on twisted cuprate heterostructures.

Highlights the inherent noise protection due to d-wave order parameter.

Lays the groundwork for high-coherence hybrid superconducting devices.

Abstract

Van-der-Waals (vdW) assembly enables the fabrication of novel Josephson junctions utilizing an atomically sharp interface between two exfoliated and relatively twisted $\rm{Bi_2Sr_2CaCu_2O_{8+x}}$ (Bi2212) flakes. In a range of twist angles around $45^\circ$, the junction provides a regime where the interlayer two-Cooper pair tunneling dominates the current-phase relation. Here we propose to employ this novel junction to realize a capacitively shunted qubit that we call flowermon. The $d$-wave nature of the order parameter endows the flowermon with inherent protection against charge-noise-induced relaxation and quasiparticle-induced dissipation. This inherently protected qubit paves the way to a new class of high-coherence hybrid superconducting quantum devices based on unconventional superconductors.