Master Degree / Yüksek Lisans Tezleri

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

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COAR Access Rights: search.filters.coarAccessRights.embargoed accessDepartment: search.filters.department.Thesis (Master)--İzmir Institute of Technology, Physics

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  • Master Thesis
    Entanglement and Topological Phenomena in Quantum Walks
    (01. Izmir Institute of Technology, 2023) Gökalp, Harun; Çakır, Özgür
    Quantum walk, a counterpart of classical random walk, is widely used in the development of quantum algorithms and the modelling of physical systems. Since it has a simple and powerful mathematical structure, its implementation in physical systems serves to solve complex problems. In one-dimensional space, we investigated the topological properties of the simple quantum walk, and under which conditions the simple quantum walk possesses winding numbers. Then, we introduced the split-step quantum walk in a twodimensional space and numerically obtained Chern number phase diagram of each band as a function of rotation parameters. Subsequently, we introduced and studied the quantum walk protocols governed by two coins in a two-dimensional space. We first explored the entanglement and topological properties of a quantum walk protocol governed by a single non-local two-coin operator followed by translations along two spatial directions each governed by a different coin. We deduced that the motion reduces to one-dimensional motion in two spatial directions in decoupled coin subspaces. Then, we studied the split-step quantum walk protocols, where each step is comprised of local coin operations, followed by translations, non-local coin operations, and translations again. In these protocols, each step involves two translations along two spatial directions, and translations along a given spatial direction were either governed by the same coin or alternating coins. We also explored three different non-local coin operations, where a collective rotation takes place in a coin space conditioned on the state of the other coin's state along the same direction or perpendicular direction. We identified the effective Hamiltonian of the system and determined its eigenstates which are comprised of four bands in the Brillouin zone. For all the protocols we have introduced, we studied the coin-coin entanglement and topological properties as a function of coin rotation parameters.
  • Master Thesis
    Effects of Dark Photons on Pulsar Kicks
    (Izmir Institute of Technology, 2012) Tosun, Onur; Demir, Durmuş Ali
    Several studies that have been carried out on supernova explosions and their remnants (pulsars) so far ended up with two fundamental problems: How are the left-handed neutrinos released out of the star and how do the supernova explosions happen even the inner core region of the star is extremely dense for propagation of the left-handed neutrinos? How can the pulsars attain very high kick velocities after the burst? The main goal of this thesis is to contribute to resolutions of the aforementioned problems by using new particles. The particles under concern are dark-photon which is immune to all the forces in the SM but gravity and interacts with the SM spectrum through only its kinetic mixing with the photon (actually the hypercharge gauge boson) and the right-handed neutrino which posseses dark electric charge (couples to dark photon). By proposing new particles, we find an interval for the photon-dark photon mixing parameter consistent with the values proposed by the string theory and the experiments. We calculate some pulsar kick velocities consistent with the observations for some magnetic field values and mixing parameter values. We show that the right-handed neutrinos may have electric charges which are not quantized and on the order of 10−6e.