Flux-Tunable Regimes and Supersymmetry in Twisted Cuprate Heterostructures

Van der Waals (vdW)assembly allows for the creation of Josephson junctions in an atomically sharpinterface between two exfoliated Bi2Sr2CaCu2O8+δ(Bi-2212) flakes thatare twisted relative to each other. In a narrow range of angles close to 45◦, the junction exhibitsa regime where time-reversal symmetry can be spontaneously broken and it can beused to encode an inherently protected qubit called flowermon. In this work weinvestigate the physics emerging when two such junctions are integrated in aSQuID circuit threaded by a magnetic flux. We show that the flowermon qubitregime is maintained up to a finite critical value of the magnetic field and,under appropriate conditions, it is protected against both charge and fluxnoise. For larger external fluxes, the interplay between the inherent twistedd-wave nature of the order parameter and the external magnetic flux enables theimplementation of different artificial atoms, including a flux-biased protectedqubit and a supersymmetric quantum circuit.

Article：arXiv:2405.03454v1