Optimal Control and Glassiness in Quantum Sensing

The extreme responsiveness of qubits to their external environment has proven to be very useful for the purpose of quantum sensing. While this is valuable for sensing small target fields, this also makes the qubits very susceptible to disruption by external noise. We simulate the use of quantum optimal control to control the qubits for sensing protocols. Our work extends the pioneering results of Poggiali et al [PRX 8, 021059 (2018)] by allowing the use of non-pi pulses. We show that this added complexity translates into both improved sensitivity and qualitative modifications of the control landscape. In particular, we explore the connection of the rough control landscape to that of a (classical) spin glass and comment on possible applications of this connection to improving quantum sensing more broadly.