Capacitively Shunted Flux Qubits and Asymmetric Transmons for Multi-Qubit Operations

Capacitively shunted flux qubits (CSFQs) and asymmetric transmons (ATs) are both flux-tunable qubits with their own merits. CSFQs with high coherence hold promise for improved single- and two-qubit gate operations due to their relatively large and positive anharmonicity. Meanwhile, ATs with optimized asymmetry provide flexibility on frequency tuning without excessive penalties on qubit coherence. Pairing a CSFQ and AT on the same chip may provide a novel regime for two-qubit operations. We present measurements of the coherence of CSFQs and ATs, and also discuss the possibility of two-qubit cross-resonance (CR) gates between them.