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CNAA / Theses / 2022 / June /

Cooperative transfer between multi-level radiators at their interaction through free vacuum and cavity


Author: Bîzgan Serghei
Degree:doctor of physics and mathematics
Speciality: 01.04.02 - Theoretical and mathematical physics
Year:2022
Scientific adviser: Nicolae Enache
doctor habilitat, professor, Institute of Applied Physics of the
Institution: Institute of Applied Physics of the

Status

The thesis was presented on the 22 June, 2022
Approved by NCAA on the 30 September, 2022

Abstract

Adobe PDF document1.09 Mb / in romanian

Thesis

CZU 538.9(043.3)

Adobe PDF document 2.57 Mb / in romanian
119 pages


Keywords

optical microcavity, radiators, quantum inseparability, cooperative effects, phase transition, Bose-Einstein condensate

Summary

Structure of the thesis: The thesis was elaborated at the Institute of Applied, Chisinau, 2021, is written in Romanian and consists of introduction, 4 chapters, general conclusions and recommendations, 176 bibliographic titles, 103 pages of basic text, 28 figures. The results presented in the thesis are published in 9 scientific papers.

Field of study: cooperative effects between atoms and cavities.

The aim of the thesis: Description of the cooperative quantum effects in systems formed by radiators (atoms, molecules etc.) at their interaction through the free or electromagnetic field of cavity and possibilities of their application in the transmission and processing of quantum information.

Objectives of the thesis: to analyze the interaction between coupled optical cavities, doped with quantum emitters; to detect the phenomenon of quantum entanglement between atoms placed in distinct optical cavities; to demonstrate that indistinguishability between atoms and/or photons can reduce the number of degrees of freedom by the formation of Hilbert subspaces, which would allow for a simplified solving of the problem; to demonstrate the possibility to direct the Bose-Einstein phase transition of small mass atoms in nonlinear exchange interaction; to identify the possibilities to use optical materials in the decontamination process for the efficient spread of UV radiation throughout the volume of the contaminated fluid.

Scientific novelty and originality: for the first time it was performed the study of quantum systems consisting of coupled optical cavities, doped with quantum emitters; it was suggested to use the symmetry of quantum systems like photonic molecule to significantly reduce the size of the Hilbert space; it was studied the dynamics of the quantum system formed by an atom moving through electromagnetic modes propagating in the opposite direction; the Bose-Einstein phase transition of atoms with small mass under the influence of heavy atoms in case of nonlinear interaction between species was investigated for the first time.

The solved scientific problem consists of the description of the cooperative phenomena, which appear both between coupled cavities doped with optical emitters and in the non-linear Bose-Einstein condensate in a mixture of bosonic gases. The possibilities of directing the information encapsulated in the polarization of the optical emitters in the presence of cooperative interaction through the evanescent field of cavities were described.

The obtained scientific results consist of the presentation of the physical modeling of cooperative phenomena and their influence on the dynamics of interacting quantum systems, the reconceptualization of the principle of indistinguishability by using it for cavity mode excitations, developing the model describing Bose-Einstein condensation in a bosonic gas mixture.

Theoretical Significance: It is analysed the possibility of using the symmetry of rotation related to the coupling between cavities by packing them in photonic molecules, on the formation of Hilbert subspaces, which allows the simplified solution of the problem. It is investigated the indirect cooperative interaction between two degenerated modes of cavity through the moving atom. This indirect interaction can be directed by the speed of the atom, that essentially changes the symmetry of the interaction between the atom and the modes of cavity. The nonlinear Bose-Einstein phase transition that occurs in the twocomponent bosonic gas is proposed in the presence of binary interaction bosons with different critical condensation temperatures.

Application value: The physical systems described in the thesis could be used to create a new class of sensors with increased sensitivity, to create logical circuits for the processing of quantum information. The cooperative effects investigated in the Bose-Einstein condensation in a mixture of bosonic gases and the possibility of manipulating it would open new perspectives for scientific research into the Bose-Einstein condensation phenomenon.

Implementation of scientific results: Scientific results can be used to elaborate specialized courses for masters or doctoral students.