Finding optimized anneal paths in capacitively shunted flux qubits

Quantum annealers require accurate control and optimization of system parameters to reduce noise levels and ultimately demonstrate a computational advantage over classical algorithms.
This requires a careful characterization of the system and its behavior in response to control biases.
In this work we study a capacitively shunted flux qubit (CSFQ), and use spectroscopy and dispersive readout to extract system parameters and model the qubit.
We confirm the multi-level structure of the circuit model of the CSFQ by annealing the qubit through small gaps and observing quantum signatures of level crossing between different eigenenergies.
We then use our model to mitigate the effect of noise by finding optimized anneal paths that minimize the transition width between the flux qubit's left and right wells.