Coherent Control of Quantum Chaotic Diffusion: Models and Molecules

J. F. Kanem

Jiangbin Gong, Paul W. Brumer

Extensive phase control of quantum chaotic diffusion is demonstrated for diatomic molecules periodically kicked with microwave pulses. In particular, both complete suppression of chaotic diffusion as well as its enhancement can be achieved by varying the phase of the initial superposition state. The origin of this control in deviations from random matrix theory is also discussed. The results should motivate experiments that are relevant to both coherent control and to quantum chaos.

Jian‐Min Yuan, D.H. Feng, George M. Zaslavsky

Jiangbin Gong, Paul W. Brumer

Extensive coherent control over quantum chaotic diffusion using the kicked rotor model is demonstrated and its origin in deviations from random matrix theory is identified. Further, the extent of control in the presence of external decoherence is established. The results are relevant to both areas of quantum chaos and coherent control.

Evgeny A. Shapiro, Michael Spanner, Misha Ivanov

We consider the quantum dynamics of the kicked rotor model in the regime where the last stable resonance islands in the classical phase space disappear. It is found that phase space regions with lower local diffusion rates are able to preserve quantum population. The low-diffusion regions can be moved through phase space in a quasi-adiabatic way by smoothly varying the parameters of the kicking field. With appropriately chosen time-scales for the variation of the field parameters, wave packets initially localized around the low-diffusion areas remain localized around these regions as the regions are moved. The wave packets can then be carried to desired regions of space despite the predominantly chaotic character of the classical phase space. We also comment on the Gong–Brumer scenario of coherent control of quantum chaotic diffusion [Phys. Rev. Lett. 86 1741 (2001)]. While our phase-space inspired control has a clear semiclassical interpretation, it appears that the Gong–Brumer control has a predominantly quantum origin. Furthermore, it is found that our control over wave packet localization disappears in the deeply chaotic regime, while the Gong–Brumer control over the chaotic diffusion persists in this regime but becomes increasingly unstable with increasing chaoticity.

Warren S. Warren