Two-axis-twisting spin squeezing by multipass quantum erasure

Mingfeng Wang,1,2,* Weizhi Qu,1 Pengxiong Li,1 Han Bao,1 Vladan Vuletić,3 and Yanhong Xiao1,4,† 1Department of Physics, State Key Laboratory of Surface Physics and Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education), Fudan University, Shanghai 200433, China 2Department of Physics, Wenzhou University, Zhejiang 325035, China 3Department of Physics, MIT–Harvard Center for Ultracold Atoms, and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA 4Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China (Received 9 May 2017; published 13 July 2017)