2025/03/31 by Huang, Chen-How, Ortuzar, Jon, Cazalilla, M. A. · 1 citation
#FOS: Physical sciences #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Superconductivity (cond-mat.supr-con)
paper · doi:10.48550/arxiv.2503.23928
Chains of triangular nanographene (triangulene), recently identified as realizing the valence-bond solid phase of a spin-1 chain, offer a promising platform for quantum information processing. We propose a superconducting spin-singlet qubit based on these chains grown on a superconducting substrate. Using the numerical renormalization group (NRG), we find a manifold of two lowest-lying, isolated spin-singlet states that undergo an avoided crossing. A qubit utilizing these states is thus protected from random-field noise and quasi-particle poisoning. We also introduce a mesoscopic device architecture, based on a triple quantum dot coupled to a superconducting junction, that quantum simulates the spin chain and enables control and readout of the qubit. An effective two-level description of the device is validated using time-dependent NRG.