Pseudoscalar Meson and Decuplet Baryon Scattering Lengths

We have systematically calculated the S-wave pseudoscalar meson and decuplet baryon scattering lengths to the third order in the small scale expansion scheme of the heavy baryon chiral perturbation theory. We hope the future study may test the framework and the present predictions.Comment: 14 pages, 1 figures, 9 table

Electric field modulation of topological order in thin film semiconductors

We propose a method that can consecutively modulate the topological orders or the number of helical edge states in ultrathin film semiconductors without a magnetic field. By applying a staggered periodic potential, the system undergoes a transition from a topological trivial insulating state into a non-trivial one with helical edge states emerging in the band gap. Further study demonstrates that the number of helical edge state can be modulated by the amplitude and the geometry of the electric potential in a step-wise fashion, which is analogous to tuning the integer quantum Hall conductance by a megntic field. We address the feasibility of experimental measurement of this topological transition.Comment: 4 pages, 4 figure