Asymmetric Double-well Potential Research Articles

Isotope effects in Rochelle salt

Isotope effects on deuteration both in the static and dynamical behaviour of Rochelle salt are theoretically investigated on the basis of a two-sublattice Ising model with asymmetric double-well potential. Spontaneous polarization and static dielectric constant are numerically calculated for several values of the tunnelling integral. The dynamical susceptibility is derived from a Bloch-type equation, and the shifts of the relaxation times are calculated from this equation. The notable difference in the dynamical behaviour between Rochelle salt and KDP-type ferroelectrics is also discussed.

Tunneling in asymmetric double-well potentials

Methods previously developed for the case of a symmetric double-well potential are here extended to study tunneling in an asymmetric, piecewise harmonic, double-well potential. The approach involves the decomposition of the real stationary states into complex right- and left-moving states and the determination of exact transmission coefficients for the latter. Numerical solutions for a selection of representative parameter values are obtained for the time evolution of states which correspond initially to a Gaussian wave packet localized in the upper well. Both resonant and nonresonant cases are studied and the significance of the transmission coefficient is established for each.

Periodic orbit description of tunneling in symmetric and asymmetric double-well potentials

Semiclassical periodic orbit theory is applied to the double-well eigenvalue problem to show how this unified approach describes the quite different character of the level splitting (in the case of symmetric wells) and level shifts (in the asymmetric case) caused by tunneling. 4 figures.