Geometric spin echo under zero field

• Published in: Nature communications Vol. 7; no. 1; p. 11668
• Main Authors: Sekiguchi, Yuhei, Komura, Yusuke, Mishima, Shota, Tanaka, Touta, Niikura, Naeko, Kosaka, Hideo
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 19.05.2016; Nature Publishing Group; Nature Portfolio
• Subjects: 639/766/119/1001; 639/766/483/2802; Biosensors; Correspondence; Electrons; Humanities and Social Sciences; Magnetic fields; multidisciplinary; Random access memory; Science; Science (multidisciplinary); Symmetry
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms11668

Spin echo is a fundamental tool for quantum registers and biomedical imaging. It is believed that a strong magnetic field is needed for the spin echo to provide long memory and high resolution, since a degenerate spin cannot be controlled or addressed under a zero magnetic field. While a degenerate spin is never subject to dynamic control, it is still subject to geometric control. Here we show the spin echo of a degenerate spin subsystem, which is geometrically controlled via a mediating state split by the crystal field, in a nitrogen vacancy centre in diamond. The demonstration reveals that the degenerate spin is protected by inherent symmetry breaking called zero-field splitting. The geometric spin echo under zero field provides an ideal way to maintain the coherence without any dynamics, thus opening the way to pseudo-static quantum random access memory and non-invasive biosensors. The sensitivity of single spins to their local environment makes them promising components for future quantum information and sensing technology. Here, the authors use geometric spin echo to demonstrate the control of nitrogen-vacancies via the crystal field in diamond under zero applied fields.