Fluctuations of local fields cause decoherence of quantum objects. It is generally believed that at high temperatures, thermal noises are much stronger than quantum fluctuations unless the thermal effects are suppressed by certain techniques such as spin echo. Here we report the discovery of strong quantum-fluctuation effects of nuclear spin baths on free-induction decay of single electron spins in solids at room temperature. We find that the competition between the quantum and thermal fluctuations is controllable by an external magnetic field. These findings are based on Ramsey interference measurement of single nitrogen-vacancy center spins in diamond and numerical simulation of the decoherence, which are in excellent agreement.
@article{arxiv.1110.0331,
title = {Controllable effects of quantum fluctuations on spin free-induction decay at room temperature},
author = {Xin-Yu Pan and Gang-Qin Liu and Dong-Qi Liu and Zhan-Feng Jiang and Nan Zhao and Ren-Bao Liu},
journal= {arXiv preprint arXiv:1110.0331},
year = {2011}
}