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Quantum Chaos in Driven Power-Law Potentials: Generalized Coherent States to Wave Packet Evolution

Thesis Info

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External Link

Author

Iqbal, Shahid

Program

PhD

Institute

Quaid-I-Azam University

City

Islamabad

Province

Islamabad.

Country

Pakistan

Thesis Completing Year

2014

Thesis Completion Status

Completed

Subject

Physics

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/2518/1/2576S.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676727057564

Similar


Quantum wave packets generally spread in their time evolution except in the special case of harmonic oscillator. In bounded Hamiltonian systems, the wave packet reconstructs itself under the condintion of phase matching and manifests the phenomena of quantum revivals and fractional revivals. In an earlier work, Gazeau and Klauder proposed a formalism to construct the quantum states (generalized coherent states) for general Hamiltonian systems with discrete and continuous spectra, and proclaimed them as ‘temporally stable’, i.e. they do not spread under time evolution. In this thesis we study, first, the dispersion of Gazeau-Klauder’s ‘temporally stable’ states, and then study how to overcome the dispersion and to build non-dispersive wave packets for nonlinear dynamical systems by the use of external periodic modulation. Gazeau-Klauder coherent states are developed for power-law potentials and their evolution in space and time is analyzed. We show that these states follow classical dynamics as long as the underlying energy spectrum is linear, otherwise they follow a classical-like evolution upto a few classical periods and disperse thereafter, despite their special construction. The auto-correlation function and probability density as a function of space and time explain the spatio-temporal behavior of these states. The analysis of the wave packet dynamics and resulting recurrence phe- nomena is extended to periodically driven power-law potentials. In the pres- ence of an external periodically modulating force, these potentials may ex- hibit classical and quantum chaos. We show that the dynamics of a quantum wave packet in the modulated power law potentials manifests quantum re- currences at various time scales. We develop general analytical relations for these times and discuss their parametric dependence. We use the recurrence phenomenon as a probe to find out the signatures of nondispersive wave packets in the periodically driven systems.
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موت

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Islamic Approach towards Social Construction: An Analytical Study in the Light of Hazrat Umar Farooq’s (RA) Wisdom and Thought

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Purification, Characterization and Binding of Metals to Zinc Alpha 2-Glycoprotein Zag by Employing Various Techniques

In this thesis ―Purification, Characterization and Binding of Metals to Zinc Alpha 2-Glycoprotein (ZAG) by Employing Various Techniques‖ the development of several techniques were carried out to analyze the interaction of biologically important metals of Irving William Series. The expression and purification of the ZAG protein was also optimized for the preparation of samples. The folding to the native conformation was also carried out. That ZAG protein is present in almost all fluids of the body. Since the discovery of ZAG, several studies have been carried out. The importance of ZAG as an important biochemical agent is known long before. The growing number of literature since today demonstrates that it’s an important biomarker for the cancer cachexia, prostate cancer, lipid mobilizing agent and obesity suppressor. The crystal structure of ZAG reveals that the fold and distribution of domains are similar to the Major histocompatibility complex-I (MHC-I) molecules. This class is known for their immune regulation and thus ZAG is believed as a central player in the immune system and cellular signaling. There is no clear evidence of ZAG participation in the cancerous conditions but over expression is dealt as a biomarker. The study shows that the ZAG interacts with several ligands. There interaction with metals is known for boosting the bioactivity of ZAG. Although, it’s believed long ago that the ZAG is an important protein that participate in several biochemical processes and little is known to understand the ligands bound conformations of ZAG with their targets like peptides and metals. In this current project, we were focused to get the good expression and purification procedure for the preparation of ZAG. The unnative aggregated fold of ZAG from the inclusion bodies was transformed into the native fold using refolding and dialysis method optimization. The introduction of histidine tag to the C-terminal and their successful removal by the Carboxypeptidase Y enzyme was also carried out. The results of the cleavage of histidine tag were evaluated with gel electrophoresis, Mass Spectrometry and Fluorescence Spectroscopy. The confirmation of native fold and bioactivity was also confirmed from DAUDA binding affinity using fluorescence emission. The formation of metal complex of Irving William Series with ZAG and their respective complexation analysis was also studies using MALDI-TOF MS and Fluorescence Spectroscopy. xiii It was found that the ZAG has multiple binding sites that interact with metals even in the presence of DAUDA. The X-ray tube analysis using FPXRF shows that Fe (III) and Co (II) has similar concentration of atoms bound to ZAG molecules.