Semiclassical density matrix near the top of a potential barrier
โ Scribed by Franz Josef Weiper; Joachim Ankerhold; Hermann Grabert
- Book ID
- 103896080
- Publisher
- Elsevier Science
- Year
- 1996
- Tongue
- English
- Weight
- 920 KB
- Volume
- 223
- Category
- Article
- ISSN
- 0378-4371
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โฆ Synopsis
Employing the path integral approach, we calculate the semiclassicai equilibrium density matrix of a particle moving in a nonlinear potential field for coordinates near the top of a potential barrier. As the temperature is decreased, near a critical temperature Tc the harmonic approximation for the fluctuation path integral fails. This is due to a caustic arising at a bifurcation point of the classical paths. We provide a selfconsistent scheme to treat the large quantum fluctuations leading to a nonlinear fluctuation potential. The procedure differs from methods used near caustics of the real time propagator. The semiclassical density matrix is determined explicitly for the case of asymmetric barriers from high temperatures down to temperatures somewhat below To.
Elsevier Science B.V.
๐ SIMILAR VOLUMES
It is demonstrated that barriers, like potential wells, can support localised states. However, barrier-localized states are seen to be much more short-lived compared to states localised in potential wells. These features are revealed with reference to a symmetric double-well potential by using the e