@article{71b0f8fc1c434103b2fbe0f8a1db33ba,
title = "Probing Spin Dynamics on Diamond Surfaces Using a Single Quantum Sensor",
abstract = "Understanding the dynamics of a quantum bit's environment is essential for the realization of practical systems for quantum information processing and metrology. We use single nitrogen-vacancy (NV) centers in diamond to study the dynamics of a disordered spin ensemble at the diamond surface. Specifically, we reduce the density of {"}dark{"}surface spins to interrogate their contribution to the decoherence of shallow NV center spin qubits. When the average surface spin spacing exceeds the NV center depth, we find that the surface spin contribution to the NV center free induction decay can be described by a stretched exponential with variable power n. We show that these observations are consistent with a model in which the spatial positions of the surface spins are fixed for each measurement, but some of them reconfigure between measurements. In particular, we observe a depth-dependent critical time associated with a dynamical transition from Gaussian (n=2) decay to n=2/3, and show that this transition arises from the competition between the small decay contributions of many distant spins and strong coupling to a few proximal spins at the surface. These observations demonstrate the potential of a local sensor for understanding complex systems and elucidate pathways for improving and controlling spin qubits at the surface.",
author = "Dwyer, {Bo L.} and Rodgers, {Lila V.H.} and Urbach, {Elana K.} and Dolev Bluvstein and Sorawis Sangtawesin and Hengyun Zhou and Yahia Nassab and Mattias Fitzpatrick and Zhiyang Yuan and {De Greve}, Kristiaan and Peterson, {Eric L.} and Helena Knowles and Tamara Sumarac and Chou, {Jyh Pin} and Adam Gali and Dobrovitski, {V. V.} and Lukin, {Mikhail D.} and {De Leon}, {Nathalie P.}",
note = "Funding Information: We thank Ania Jayich, Norman Yao, Soonwon Choi, Alastair Stacey, Cherno Jaye, and Andrew Evans for fruitful discussions. Undergraduate researchers Trisha Madhavan and Rohith Karur contributed to surface spin measurements that helped us to calibrate the annealing procedure. This work is supported in part by the DARPA DRINQS program (Grants No. D18AC00015 and No. D18AC00033), the Center for Ultracold Atoms (NSF PHY-1734011), and the Moore Foundation (Grant No. 4342.01). Sample surface preparation and spectroscopy was partially supported by the NSF under the CAREER program (Grant No. DMR-1752047) and through the PCCM (Grant No. DMR-1420541). L.V.H.R. acknowledges support from the DOD through the NDSEG Fellowship Program. E.K.U. acknowledges support from the NSFGRFP (Grant No. DGE1144152). D.B. acknowledges support from the NSFGRFP (Grant No. DGE1745303) and the Hertz Foundation. S.S. acknowledges support from the PMU-B (Grant No. B05F630108). J.C. acknowledges financial support from the MST, Taiwan (MOST-109-2112-M-018-008-MY3). M.F. is supported by an appointment to the IC Postdoc Research Program by ORISE through an interagency agreement between the U.S. DOE and the ODNI. A.G. acknowledges support from the NKFIH in Hungary for the Quantum Technology Program (Grant No. 2017-1.2.1-NKP-2017-00001), the National Excellence Program (Grant No. KKP129866), the Quantum Information National Laboratory, and the EU QuantERA II MAESTRO project and from the European Commission for the ASTERIQS and QuMicro projects (Grant No. 820394 and No. 101046911). V.V.D. is partially supported by QuTech Physics Funding (QTECH, program 172, No. 16QTECH02), which is partly financed by the NWO. This work was performed in part at the Imaging and Analysis Center at Princeton, the Center for Nanoscale Systems at Harvard (NSF Grant No. 1541959), and the research beam line U7A of the National Synchrotron Light Source operated for the DOE by Brookhaven National Laboratory (Contract DE-AC02-98CH10886). Publisher Copyright: {\textcopyright} 2022 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the {"}https://creativecommons.org/licenses/by/4.0/{"}Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.",
year = "2022",
month = oct,
doi = "10.1103/PRXQuantum.3.040328",
language = "English (US)",
volume = "3",
journal = "PRX Quantum",
issn = "2691-3399",
publisher = "American Physical Society",
number = "4",
}