On May 30th, Prof. Liu Renbao from the Chinese University of Hong Kong (CUHK) visited Wuhan Institute of Physics and Mathematics (WIPM, CAS) and delivered a lecture entitled “Control of spin decoherence and applications”.

In modern nanotechnology and quantum science, the relevant environment of a quantum object can be of nanometre or even sub-nanometre size, i.e. the environment itself is quantum in nature. The coupling between a quantum object and its environment causes decoherence, which is a key issue in quantum science and technology.

In his lecture, Prof. Liu gave a detailed introduction about the decoherence of quantum objects in quantum science and technology. For example, the nitrogen-vacancy (NV) centre in high-purity diamond, which has an electron spin-1 coupled to a nanometre-sized nuclear spin bath, is an ideal system to study some fundamental aspects of electron spin decoherence. They explained the multi-pulse dynamical decoupling control of decoherence of spins higher than 1/2, to elongate the centre spin coherence time (~millisecond), in the basis of the quantum theory. The anomalous decoherence effect (ADE) is robust against the details of the decoherence mechanisms but is a universal phenomena due to the quantum nature of mesoscopic baths. By dynamical decoupling control, the spin coherence can be preserved for high-sensitivity magnetometry and even single-molecule nuclear magnetic resonance (NMR). Some potential applications, in particular, atomic-scale magnetometry, single-molecule nuclear magnetic resonance, and detection of many-body correlations in baths were also discussed.

The lecture attracted experts and students both in experimental and theoretical research. At the end, Prof. Liu carried out communication and discussion with research staff and students. Later, he visited the laboratories of the division of Atomic, Molecular and Optical Physics (AMOP). Furthermore, Prof. Liu discussed the possibility to cooperate with the teams of WIPM on the work of the precision measurements based on cold atoms, quantum degenerated gases, quantum information, quantum optomechanic, and so on.