Design improvements for superconducting qubits

Rapid understanding of decoherence processes, both energy and phase relaxation, for superconducting qubits led to novel design modifications with which various qubit performance metrics were improved dramatically. One example of a successfully redesigned qubit is the Transmon qubit. Here we show that there are other modifications that can made bestowing qubits with properties which we believe are advantageous for multi-qubit applications. Specifically we highlight two modifications for two types of qubits and compare these with experimental results. The first is a modified flux qubit which is less sensitive to some of the known decoherence sources. The second is a microwave-based read-out for phase qubits which completely avoids some of the decoherence mechanisms that were recently shown to limit qubit performance.