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Dissipative Quantum Dynamics and Decoherence
Umeå University, Faculty of Science and Technology, Department of Physics.
2011 (English)Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

Abstract This thesis has two parts, in the first, the Caldeira-Leggett model is introduced; its derivation and general consequences are explored following a paper by Caldeira and Leggett[1]. An operator-formalism shortcut through some of the more mathematically cumbersome parts of the derivation of the model is also developed. The correlation of the force resulting from reservoir-interaction is examined in the high- and low-temperature limits, and the Langevin equation is shown to emerge in the classical limit.Abstract The second part introduces decoherence through a thought experiment that demonstrates the destructive effect of random phase shifts on interference terms, and then follows another paper by Caldeira and Leggett[2] in applying their model further to study the phenomenon of dissipative decoherence. The time-evolution of the interference terms in a superposition of Gaussian wave packets in a harmonic oscillator potential is studied when interacting with a heat bath, and they are shown to vanish at a rate much faster than the relaxation of the system.

Place, publisher, year, edition, pages
2011. , 85 p.
Keyword [en]
decoherence, quantum mechanics, dissipation, caldeira-leggett
National Category
Physical Sciences
URN: urn:nbn:se:umu:diva-44341OAI: diva2:420243
Available from: 2011-06-13 Created: 2011-05-31 Last updated: 2011-06-13Bibliographically approved

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Löfgren, Viktor
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