title: Observation of an anomalous decoherence effect in a quantum bath at room temperature.
abstract: The decoherence of quantum objects is a critical issue in quantum science and technology. It is generally believed that stronger noise causes faster decoherence. Strikingly, recent theoretical work suggests that under certain conditions, the opposite is true for spins in quantum baths. Here we report an experimental observation of an anomalous decoherence effect for the electron spin-1 of a nitrogen-vacancy centre in high-purity diamond at room temperature. We demonstrate that, under dynamical decoupling, the double-transition can have longer coherence time than the single-transition even though the former couples to the nuclear spin bath as twice strongly as the latter does. The excellent agreement between the experimental and theoretical results confirms the controllability of the weakly coupled nuclear spins in the bath, which is useful in quantum information processing and quantum metrology.
authors.affiliation: Hefei National Laboratory for Physical Sciences at the Microscale, Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Pu
authors.initials: P
authors.lastname: Huang
authors.forename: Xi
authors.initials: X
authors.lastname: Kong
authors.forename: Nan
authors.initials: N
authors.lastname: Zhao
authors.forename: Fazhan
authors.initials: F
authors.lastname: Shi
authors.forename: Pengfei
authors.initials: P
authors.lastname: Wang
authors.forename: Xing
authors.initials: X
authors.lastname: Rong
authors.forename: Ren-Bao
authors.initials: RB
authors.lastname: Liu
authors.forename: Jiangfeng
authors.initials: J
authors.lastname: Du
mesh_terms: D002247:Carbon Isotopes / Q000737:chemistry; D003460:Crystallization; D018130:Diamond / Q000032:analysis*; D004578:Electron Spin Resonance Spectroscopy; D004583:Electrons; D007257:Information Theory; D007834:Lasers; D008872:Microwaves; D008962:Models, Theoretical; D036103:Nanotechnology / Q000379:methods* / Q000706:statistics & numerical data; D009584:Nitrogen / Q000737:chemistry; D011789:Quantum Theory; D019097:Spin Trapping; D013696:Temperature
chemical_list: D002247:Carbon Isotopes; D018130:Diamond; D009584:Nitrogen