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Resonance effects at interaction of two quantum subsystems”


Author: Ciobanu Nellu
Degree:doctor of physics and mathematics
Speciality: 01.04.02 - Theoretical and mathematical physics
Year:2009
Scientific adviser: Nicolae Enache
doctor habilitat, professor, Institute of Applied Physics of the ASM
Scientific consultant: Anatol Rotaru
doctor habilitat, professor, Academy of Economic Studies of Moldova
Institution:
Scientific council:

Status

The thesis was presented on the 25 September, 2009
Approved by NCAA on the 5 November, 2009

Abstract

Adobe PDF document0.44 Mb / in romanian

Keywords

quantum reversibility, entangled states, resonance cooperative effects, spontaneous emission, electromagnetic field vacuum, indistinguishable radiators, resonant fluorescence, travelling and standing wave, autocorrelation function, master equation, bunching.

Summary

The thesis is dedicated to the resonance cooperative effects of two quantum oscillators in interaction which occur in optical systems.

In this study is investigated the quantum reversibility in the case when the exchange energy between a three-level atom and the electromagnetic cavity field is realized. The exact solution of wave function of the system and the reversible conditions are obtained. These conditions describe the interaction time for which the subsystems can restore their initial state. The recursion relation is obtained in a more general case than in the literature, and in the particular case includes the dynamical and statical reversible conditions. As was demonstrated, with increasing the number of Fock states the nutations are realized between the ground and excited state. For the same number of Fock states in both modes of the field, the restoration of atomic inversion can be realized between the intermediate and excited state and intermediate and ground states. With increasing of the number of photons in the first mode, the quantum nutations which correspond to the flying time, take place between the intermediate and excited level. In the opposite situation, when the number of Fock states in the second mode is larger than in the first mode, the atomic inversion is restored only between the intermediate and ground levels. In the non-resonance case, the full reversibility is not realized. As was demonstrated only the restoration of diagonal elements of the density matrix operator is possible (atomic population, the mean of photon numbers ant its fluctuations). The total reversibility can be realized in the case when the intermediate level is not populated. Thus, the statistics of cavity field, for which the partial reversibility take place, has so a sub-Poissonian as a super-Poissonian dependence. The main idea was not only to solve these problems for an extended degree of freedoms, but to find the recursion relation that unifies the dynamical and statistical trapping effects. It also let us to study new reversible conditions.

The resonance fluorescence from a three-level system of radiators localized in laser field is discussed. The Hamiltonian of atoms dressed in the standing wave resonator and the master equation are obtained. The equation of motion of two undistinguishable atoms for various situations of localization and the exchange integrals are obtained. The correlation functions of emitted photons at the frequencies ± Ω j 31 ω were studied. In the case when the distance between the atoms is smaller than the wave length of the field, the emitted photons are strongly correlated.

The main results of the thesis were published in 21 scientific papers (8 articles and 13 abstracts).

The dissertation contains introduction, 4 chapters, conclusions, 100 references, 104 pages of the basic text and 46 figures.