Quantum quenches for enhancing qubit-based quantum noise spectroscopy

Qubit-based noise spectroscopy (QNS) techniques, where the dephasing of a probe qubit is exploited to study a system of interest, underlie some of the most common quantum sensing and noise characterization protocols. They have a variety of applications, ranging from designing effective quantum control protocols to investigating properties (phase transitions, thermodynamics, etc.) of quantum many-body systems. In this talk, I will discuss a simple and powerful strategy for enhancing standard QNS methods, making use of a quantum quench that is inadvertently induced on the probed system in a standard sensing protocol. Those quenches lead to observable changes in the sensor qubit evolution, which allow one to extract environmental response properties. While our ideas are readily applicable to a range of sensing platforms, as a concrete example, I will describe specific applications using nitrogen-vacancy (NV) centers in diamond.

Pizza and drinks will be served after the seminar in ATL 2117.