Prof. ZHENG, Hang(郑杭教授)

Department of Physics, Shanghai Jiao Tong University

  Abstract: We investigate the dynamics of a driven two-level system (classical Rabi Hamiltonian dynamics) by a very simple method based on a unitary transformation. We focus on the properties of off-resonance cases in which the traditional rotating wave approximation (Rabi-RWA) breaks down. The reformulated rotating wave method not only possesses the same simple mathematical structure of Rabi-RWA but also includes the effects of counter-rotating components. Our approach is both simply tractable and physically clear. In comparison with the results of different RWA schemes and the numerical method, we give the driven dynamics in good agreements with exact results in a wide range of parameter regime. Our main results are: (i) the dynamics of coherent destruction of tunneling and its condition; (ii) the anti-rotating modulated Rabi frequency and the calculation of the Bloch-Siegert shift; (iii) the parameter regions of validity of different methods and the comparison of dynamics of different methods. The approach provides a direct tool for studying the properties of driven systems within a rather wide parameter range.                                    

 Date&Time: January 15, 2012（Sunday） 9:30 – 10:30 a.m.
Location: 606 Conference Room