Quantum decoherence and quantum state diffusion formalism

Dumlu, Cesim Kadri
Foundational problems of quantum theory, regarding the appearance of classicality and the measurement problem are stated and their link to studies of open quantum systems is discussed. This study's main aim is to analyze the main approaches that are employed in the context of open quantum systems. The general form of Markovian master equations are derived by a constructive approach. The Quantum State Diffusion (QSD) formalism is stressed upon as an alternative method to the master equations. Using the Caldeira-Leggett model in the context of QSD, stationary solutions of a charged particle exposed to a uniform magnetic field are found. The important points are summarized and the results are discussed.


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In this thesis, higher derivative theories are investigated. Ostrogradskian instability of higher derivative theories is examined both at the classical and quantum levels. It is shown that avoiding the instability in nondegenerate higher derivative theories is impossible. Moreover, the degenerate model of relativistic particle with a curvature term is studied as a viable higher derivative theory. Most of the work we present here is not original. We give a review of the literature and compile various detache...
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Citation Formats
C. K. Dumlu, “Quantum decoherence and quantum state diffusion formalism,” M.S. - Master of Science, Middle East Technical University, 2007.