Noise spectroscopy of a quantum-classical environment with a diamond qubit
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2018-12-17 |
| Journal | Physical review. B./Physical review. B |
| Authors | Santiago HernĂĄndez-GĂłmez, Francesco Poggiali, Paola Cappellaro, Nicole Fabbri |
| Institutions | University of Florence, National Institute of Optics |
| Citations | 40 |
Abstract
Section titled âAbstractâKnowing a quantum systemâs environment is critical for its practical use as a\nquantum device. Qubit sensors can reconstruct the noise spectral density of a\nclassical bath, provided long enough coherence time. Here we present a protocol\nthat can unravel the characteristics of a more complex environment, comprising\nboth unknown coherently coupled quantum systems, and a larger quantum bath that\ncan be modeled as a classical stochastic field. We exploit the rich environment\nof a Nitrogen-Vacancy center in diamond, tuning the environment behavior with a\nbias magnetic field, to experimentally demonstrate our method. We show how to\nreconstruct the noise spectral density even when limited by relatively short\ncoherence times, and identify the local spin environment. Importantly, we\ndemonstrate that the reconstructed model can have predictive power, describing\nthe spin qubit dynamics under control sequences not used for noise\nspectroscopy, a feature critical for building robust quantum devices. At lower\nbias fields, where the effects of the quantum nature of the bath are more\npronounced, we find that more than a single classical noise model are needed to\nproperly describe the spin coherence under different controls, due to the back\naction of the qubit onto the bath.\n