Quantum Sensing with Interferometer Based on Superconducting Circuits

In traditional interferometers, such as Mach-Zehnder interferometer, the interference arises from splitting and recombining light beams via beam splitters. Coherent light is split into two different paths. Each light wave accumulates different phases. After recombination, fringes appear as a function of the phase difference between the two light waves. Sensing is achieved by phase changes due to the small change of sensing quantity. Superconducting circuits provide a clear platform to study the fundamentals of interferometry, as well as technological advancements. The ability to engineer and tailor the light-matter interaction is the key advantage of superconducting circuits. In this proposal, we will experimentally study nonlinear interferometers at microwave frequencies using superconducting artificial atoms. We will develop the key components of a Mach-Zehnder interferometer based on light-matter interaction in the form of microwave photons and superconducting artificial atoms. This includes the construction of a tunable beam splitter, a tunable beam combiner, and a tunable phase shifter dependent on magnetic fields. Finally, we will combine all these components to construct a Mach-Zehnder interferometer and use it to sense magnetic fields.