Leveraging Exact Many-spin Dynamics to Build Noise Spectroscopy Dictionaries for Quantum Sensing

A quantum sensor is a device that can map its local environment by extracting specific signals from its noisy surroundings. In recent years, obtaining the noise spectrum of a quantum sensor under the application of dynamical decoupling pulse sequences has become a popular route to identify the sources of noise in a frequency-resolved manner. However, to effectively interpret noise spectra, we require a microscopic understanding of how unique magnetic environments imprint specific signatures in the measured coherence decay of a quantum sensor. In this presentation, I will introduce our numerically exact tensor network method, which can predict the coherence dynamics of interacting many-spin systems. I will illustrate how this method can be combined with our variational noise spectroscopy protocol to generate an interpretable dictionary for the magnetic environment of a quantum sensor. I will demonstrate the broad applicability of our approach by using it to understand the unique spin physics of Nitrogen Vacancy (NV) centers and molecular qubit quantum sensors.