Abstract: This paper briefly reviews the authors interactions with and guidance received from Professor Chen Shigang. Professor Chen has a profound theoretical foundation, and his academic guidance to the author is highly inspiring. For instance, in research on the critical behavior of Bose-Einstein condensates in double wells and large spin tunneling, he put forward key ideas and guided the author to improve the research. Chen Shigang is skilled in applying methods such as linearization and perturbation to study complex physical processes, which has a profound impact on the author. The paper also presents Professor Chens life attitude of being quiet, focused and passionate about science, and expresses wishes for his 90th birthday.

Key words:  Strong-Field Physics, Hamiltonian, Bose-Einstein Condensate, Large-Spin Tunneling