Design and simulation of complex superconducting circuits for advanced quantum annealing hardware

The hardware characteristics likely to maximize the computational potential of quantum annealing machines almost certainly include: (i) high spin coherence; (ii) complex and high-connectivity Ising interactions between spins; and (iii) multi-spin, non-stoquastic quantum fluctuations. In this talk, I will describe our work at MIT-LL on the design and simulation of superconducting circuits with the potential to achieve some or all of these characteristics. Specifically, I will present a new type of superconducting flux qubit, uniquely suited to emulating a quantum spin, called the Josephson phase-slip qubit, and the architecture in which we plan to embed it, based on paramagnetic coupler trees. In addition, I will discuss possible circuits for implementing quantum error suppression using these qubits, and for engineering the multi-qubit interactions needed to exploit them. Finally, I will describe the simulation methodology which allows us to capture the low-energy physics of these complex circuits.