Quantum sensing with superconducting microwave circuits

Quantum mechanics offers intriguing opportunities for sensing applications with accuracies beyond the classically obtainable limits. An especially interesting approach is based on using entangled microwave photons for radar applications [Las Heras et al., Sci. Rep., 7, 9333 (2017)]. Here, we discuss a novel frequency-degenerate scheme for quantum sensing with superconducting microwave circuits. Our method is based on continuous variables that provide a convenient platform for quantum communication [Pogorzalek et al., Nat. Commun., 10, 2604 (2019)]. The same microwave regime is utilized in conventional radars owing to the transparency window of the atmosphere. Hence, our scheme suffers no conversion losses and, therefore, is promising for future real-world applications.