Quantum entangled and squeezed spin states are useful for quantum computing, quantum information processing, and quantum precision measurement. However, these delicate quantum states are very fragile to the uncontrolled environmental or laboratory noises. Thus, the generation and the storage of these quantum states in a noisy environment become a main obstacle to prevent them from pactical applications.
Dynamical decoupling (DD) is an active and effective method for suppressing decoherence of a quantum system from its environment. In this talk, we will discuss the generation of several entangled quantum states, such as optimal spin squeezed states, the many-body singlet states and the twin-Fock states, in a spin-1 BEC with the presence of practical laboratory noises. In order to suppress the noise effect during the production of these entangled states, we employ the well-known biaxial dynamical decoupling protocol developed long ago by NMR scientists, as well as new Uniaxial DD (Uni-DD) protocol proposed recently by us. The storage of the squeezed spin states will also be considered.

References:
[1] Peng Xu, Su Yi, and Wenxian Zhang*, "Efficient generation of many-body entangled states by multilevel oscillations", Phys. Rev. Lett. 123, 073001 (2019).
[2] Qi Yao, Jun Zhang, Xiao-Feng Yi, Li You, and Wenxian Zhang*, “Uniaxial dynamical decoupling for an open quantum system”, Phys. Rev. Lett. 122, 010408 (2019).
[3] Peng Xu, Huanying Sun, Su Yi, and Wenxian Zhang*, "Rebuilding of destroyed spin squeezing in noisy environments", Sci. Rep. 7, 14102 (2017).
[4] Huanying Sun, Peng Xu, Han Pu, and Wenxian Zhang*, “Efficient generation of many-body singlet states of spin-1 bosons in optical superlattices”, Phys. Rev. A 95, 063624 (2017).
[5] Jun Zhang, Yingying Han, Peng Xu, and Wenxian Zhang*, “Preserving coherent spin and squeezed spin states of a spin-1 Bose-Einstein condensate with rotary echoes”, Phys. Rev. A 94, 053608 (2016).

张文献，男，博士，1997年和2000年在复旦大学物理系分别获学士学位和硕士学位，2005年在美国佐治亚理工学院物理系获博士学位（Ph.D.）。2005－2007年在美国Ames国家实验室和衣阿华州立大学作博士后,2007－2008年在达特茅斯学院物理与天文系从事研究。2008年－2011年在复旦大学信息学院光科学与工程系工作，任副研究员。2012年调入武汉大学物理科学与技术学院，任教授。主要从理论方面研究超冷原子气体、光与物质的相互作用、量子计算及量子信息处理等。已在国内外学术刊物上发表SCI论文60余篇，其中包括1篇Nature Physics，4篇Physical Review Letters，多篇Physical Review A/B/E等，被引用超过1600次，h因子达到20。主持和参加了多项国家科技部、基金委、教育部科研项目。2010年获教育部新世纪优秀人才，2012年获湖北省“楚天学者”特聘教授。