Master Degree / Yüksek Lisans Tezleri

Permanent URI for this collectionhttps://hdl.handle.net/11147/3008

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Subject: search.filters.subject.Open quantum systems

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  • Master Thesis
    Quantum Dynamics of Noise Assisted Excitation Transport
    (Izmir Institute of Technology, 2018) Özkan, Hazan; Çakır, Özgür; Çakır, Özgür; 04.05. Department of Pyhsics; 04. Faculty of Science; 01. Izmir Institute of Technology
    In this thesis, different types of systems are studied to investigate the effects of the environmental factors on diffusion and transfer time. Each system consists of different energy levels and excitation transfers between them. The mismatch between the energy levels leads to the Anderson localization. Localization has a negative effect on transport. It is shown that Anderson localization is suppressed due to interaction with the environment. To describe the dynamical evolution of the open quantum system Lindblad master equation is used. The transition times of the system from the pure state to the completely mixed state are examined with the help of the density matrix. In consequence of our study, because of the interaction between the system and environment the change in the wavefunction, the loss in the interference terms and an irreversible information flow in the total system are observed. Destructive effects of the environmental noise on localization are observed for different scenarios and diffusion enhanced. However, when the interaction with the environment becomes larger than a critical value, the system exhibits Zeno effect. In the Zeno regime, the time evolution of the quantum state of the system as well as the diffusion is suppressed.
  • Master Thesis
    Quantum Control and Generation of Quantum Entanglement
    (Izmir Institute of Technology, 2014) Altuğ, Sevil; Çakir, Özgür; 01. Izmir Institute of Technology
    In this thesis, the generation of entanglement is studied in a controlled environment. The model system of interest includes a cavity field interacting with a pair of atoms. The cavity field is heavily damped and it is pumped in order to maintain a steady state field population. Thus, we can eliminate the cavity field adiabatically and obtain the master equation describing only the qubits evolution in time. At first, this system is analyzed in the steady state, without making any measurement on the photons leaking through the cavity walls. In this way, the ideal physical parameter set for maximum entanglement in this model is investigated. In the second step, we assume a direct measurement on the leaking cavity photons, and observe the evolution of entanglement in a quantum trajectories approach. We simulate quantum trajectories approach by applying Monte Carlo method. The amount of entanglement is obtained as a function of time and number of photon detections.