title: Uncovering many-body correlations in nanoscale nuclear spin baths by central spin decoherence.
abstract: Central spin decoherence caused by nuclear spin baths is often a critical issue in various quantum computing schemes, and it has also been used for sensing single-nuclear spins. Recent theoretical studies suggest that central spin decoherence can act as a probe of many-body physics in spin baths; however, identification and detection of many-body correlations of nuclear spins in nanoscale systems are highly challenging. Here, taking a phosphorus donor electron spin in a (29)Si nuclear spin bath as our model system, we discover both theoretically and experimentally that many-body correlations in nanoscale nuclear spin baths produce identifiable signatures in decoherence of the central spin under multiple-pulse dynamical decoupling control. We demonstrate that under control by an odd or even number of pulses, the central spin decoherence is principally caused by second- or fourth-order nuclear spin correlations, respectively. This study marks an important step toward studying many-body physics using spin qubits.
authors.affiliation: 1] State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China [2] Department of Physics, The Chinese University of Hong Kong, Hong Kong, China [3] Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Wen-Long
authors.initials: WL
authors.lastname: Ma
authors.affiliation: 1] London Centre for Nanotechnology, University College London, London WC1H 0AH, UK [2] Department of Materials, Oxford University, Oxford OX1 3PH, UK.
authors.forename: Gary
authors.initials: G
authors.lastname: Wolfowicz
authors.affiliation: Beijing Computational Science Research Center, Beijing 100084, China.
authors.forename: Nan
authors.initials: N
authors.lastname: Zhao
authors.affiliation: 1] State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China [2] Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Shu-Shen
authors.initials: SS
authors.lastname: Li
authors.affiliation: 1] London Centre for Nanotechnology, University College London, London WC1H 0AH, UK [2] Department of Electronic and Electrical Engineering, University College London, London WC1E 7JE, UK.
authors.forename: John J L
authors.initials: JJ
authors.lastname: Morton
authors.affiliation: 1] Department of Physics, The Chinese University of Hong Kong, Hong Kong, China [2] Center for Quantum Coherence, The Chinese University of Hong Kong, Hong Kong, China [3] Institute of Theoretical Physics, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Ren-Bao
authors.initials: RB
authors.lastname: Liu