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Long-time and unitary properties of semiclassical initial value representations
C Harabati1, J M Rost, F Grossmann
1Max-Planck Institute for the Physics of Complex Systems, Nothnitzer Strasse 38, D-01187 Dresden, Germany. harabati@mpipks-dresden.mpg.de
The Journal of Chemical Physics
|July 23, 2004
Summary
We compared two semiclassical quantum dynamics methods. A revised thawed Gaussian propagator shows similar accuracy to the Herman-Kluk method, offering a viable alternative.
Area of Science:
- Quantum dynamics
- Computational chemistry
- Theoretical physics
Background:
- Semiclassical methods approximate quantum mechanical behavior.
- The Herman-Kluk (HK) propagator is a widely used semiclassical tool.
- The thawed Gaussian (TG) propagator offers a potentially more efficient alternative.
Purpose of the Study:
- To numerically compare the accuracy and stability of the HK and TG propagators.
- To identify the limitations of the original TG propagator.
- To develop an improved TG propagator.
Main Methods:
- Numerical simulations of quantum dynamics in nonlinear 1D potentials.
- Comparison of the HK and Baranger et al. TG propagators.
- Modification of the TG propagator with a global harmonic approximation.
Main Results:
- The original TG propagator exhibits poor long-time accuracy and norm conservation.
- The reasons for the TG propagator's limitations were identified.
- The amended TG propagator demonstrated comparable accuracy to the HK propagator.
Conclusions:
- The revised TG propagator is a robust alternative to the HK method.
- The global harmonic approximation enhances TG propagator stability.
- This work provides insights into semiclassical propagator performance.
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