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Applications of the Decoherence Formalism


Brun, Todd Andrew (1994) Applications of the Decoherence Formalism. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/zc4x-7346.


In this work the decoherence formalism of quantum mechanics is explored and applied to a number of interesting problems in quantum physics. The boundary between quantum and classical physics is examined, and demonstration made that quantum histories corresponding to classical equations of motion become more probable for a broad class of models, including linear and nonlinear models of Brownian motion. The link between noise, dissipation, and decoherence is studied. This work is then applied to systems which classically exhibit dissipative chaotic dynamics. A theory is explicated for treating these systems, and the ideas are applied to a particular model of the forced, damped Duffing oscillator, which is chaotic for certain parameter values. Differences between classical and quantum chaos are examined, particularly differences arising in the structure of fractal strange attractors, and the conceptual difficulties in framing standard notions of chaos in a quantum system. A brief discussion of previous work on quantum chaos is included, and the differences between Hamiltonian and dissipative chaos pointed out; a somewhat different interpretation of quantum chaos from the standard one is suggested. A class of histories for quantum systems, in phase space rather than configuration space, is studied. Different ways of representing projections in phase space are discussed, and expressions for the probability of phase space histories are derived; conditions for such histories to decohere are also estimated in the semiclassical limit.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Physics ; Decoherence Formalism
Degree Grantor:California Institute of Technology
Division:Physics, Mathematics and Astronomy
Major Option:Physics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Gell-Mann, Murray
Group:Caltech Theory
Thesis Committee:
  • Unknown, Unknown
Defense Date:18 April 1994
Record Number:CaltechETD:etd-03132009-091544
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:946
Deposited By: Imported from ETD-db
Deposited On:16 Mar 2009
Last Modified:16 Apr 2021 22:25

Thesis Files

PDF (Brun_ta_1994.pdf) - Final Version
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