A method for calculating nonadiabatic polarization response on time-dependent external fields is presented. Physical content is represented by model Hamiltonians for macroscopic variables as well as the noise terms emerged from microscopic degrees of freedom. The mathematical technique is based on the formal analogy between polarization response in ferroelectrics and the symplectic integration technique for quantum electron dynamics. Test solutions for zero-dimensional and spatially extended problems imply that this method has potential for large scale of problems associated with long-range terms in the model Hamiltonians and boundary problems originated from electrodes, substrates and relevant technological restrictions.
Acknowledgments
This work has been partially supported by the Contract No. ICA1-CT-2000-70007 of European Excellence Center of Advanced Material Research and Latvian Science Project Nr.01.0805.1.1.
Paper originally presented at IMF-11, Iguassu Falls, Brazil, September 5–9, 2005;