Two Anderson impurities coupled through a superconducting island: charge stability diagrams and double impurity qubit

• DOI: 10.48550/arxiv.2303.14410
• Publication Date: 2023-01-01
• Authors: Filip K. Malinowski
• Keywords: Dephasing; Anderson impurity model; Charge qubit

We present a model of two Anderson impurities coupled to and through superconducting island. The parametrizes the strength coupling between impurity sites, allowing it represent variable distance impurities. systematically explore effect parameters in subspaces with total even odd occupancy, identifying unique features charge stability diagrams that distinguish parities. For electron parity, we identify device tuning, which splitting lowest energy states is highly insensitive changes chemical potentials. investigate degree qubit based on such tunable discuss an optimal choice maximize inhomogeneous dephasing time. Finally, point out proposed lacks transition dipole moment, outline some consequences viable driving readout mechanisms. prototype qubits could be realized existing capabilities quantum dots hard-gapped superconductors.