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- Type of Document: Ph.D. Dissertation
- Language: Farsi
- Document No: 42489 (03)
- University: Sharif University of Technology
- Department: Chemistry
- Advisor(s): Shafiee, Afshin
- Abstract:
- Although quantum mechanics has thrilled a multitude of successes since its birth, it has also generated puzzles that persist to this day. These puzzles are largely connected with the role of measurement in quantum mechanics. Therefore, we are dealing with individual phenomena and that our possibilities of handling the measuring instruments allow us only to make a choice between the different complementary types of phenomena. Within the framework of delayed-choice experiments, the choice between complementary types of phenomena is postponed to the moments after the preparation of system is a superposition state. Regarding the probability theory, we have concluded that the delayed-choice experiments can be classified into two main groups where the temporal aspect of each group is characterized differently within their probabilistic descriptions. Then, we investigate the issue of destruction of quantum coherence in non-planar molecules in gas medium. Here, the quantum superposition is spatial coherence between two minima of a double-well potential. Using the quantum Brownian motion within a nonlinear Lindblad-type equation, we have provided a physical model to show how intermolecular interactions make the tunneling incoherent, thus inducing a racemization by dephasing. We have applied our model to two interesting cases: 1) The shift to zero frequency of the inversion line of ammonia, with increase of the pressure of the gas; 2) The destruction of the coherent tunneling of D2S2 molecules in a gas of Helium. In both cases, our analysis shows a very good agreement with previous theoretical and experimental results
- Keywords:
- Complementarity Principle ; Optical Activity ; Quantum Coherence ; Delayed Choice ; Decoherence