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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Spin-dependent interactions in the three-body eikonal model

Bush, Matthew Peter January 1997 (has links)
A derivation of the elastic scattering differential cross section, within a three-body eikonal model, that treats both central and spin-orbit interactions between the constituent projectile clusters and the target is presented. This formalism is then used in the theoretical study of the scattering of 8B from 12C at 40 MeV/nucleon. The proton halo candidate, 8B, is taken to consist of a single valence proton orbiting a 7Be core cluster. Calculation of the elastic scattering amplitude relies upon determining the phase shifts caused as the projectile passes through the region of interaction with the target. A form for the orbital angular momentum operator of each projectile cluster about the target is obtained that allows a relatively simple form for the spin-orbit phase shift functions, analogous to those for the central interactions, to be deduced. The study of the angular distribution of the elastic scattering differential cross section is carried out in two parts. Initially the effect of elastic break-up and recombination of the projectile during the scattering process, only taking into account central interactions, is studied. To gauge the magnitude of these effects, within the three-body model, the elastic scattering differential cross section, in the limit of no projectile break-up, is derived. Despite the very small binding energy of 8B it is shown that these effects are quite small. It is also shown, however, that these effects become more conspicuous as the valence proton becomes less localised about the core. Finally the effect of including spin-orbit interactions is studied. In the system under study these effects are shown to have an almost negligible effect on the angular distribution of the differential cross section. However, increasing the projectile kinetic energy to the region of hundreds of MeV/nucleon is seen to increase their significance. Future calculations hope to look at the angular distribution of the elastic scattering differential cross section and vector and tensor analysing powers of polarised beams of deuterons as these systems are expected to show more sensitivity to spin- orbit interactions. Furthermore, with the possibility of polarised beams of halo nuclei, the three-body Glauber model would be an ideal theoretical tool with which to study certain of their spin-related phenomena too.
2

Enhanced triplet superconductivity in noncentrosymmetric systems

Yokoyama, Takehito, Onari, Seiichiro, Tanaka, Yukio 05 1900 (has links)
No description available.
3

Anomalous Hall effect in a two-dimensional electron gas

Nunner, Tamara S., Sinitsyn, N. A., Borunda, Mario F., Dugaev, V. K., Kovalev, A. A., Abanov, Ar., Timm, Carsten, Jungwirth, T., Inoue, Jun-ichiro, MacDonald, A. H., Sinova, Jairo 12 1900 (has links)
No description available.
4

Intrinsic anisotropic magnetoresistance in spin-polarized two-dimensional electron gas with Rashba spin-orbit interaction

Kato, Takashi, Ishikawa, Yasuhito, Itoh, Hiroyoshi, Inoue, Jun-ichiro 06 1900 (has links)
No description available.
5

Measurement and control of transverse photonic degrees of freedom via parity sorting and spin-orbit interaction

Leary, Cody Collin, 1981- 06 1900 (has links)
xv, 215 p. : ill. (some col.) A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number. / In this dissertation, several new methods for the measurement and control of transverse photonic degrees of freedom are developed. We demonstrate a mode sorter for two-dimensional (2-D) parity of transverse spatial states of light based on an out-of-plane Sagnac interferometer. The first experimental 2-D parity sorting measurements of Hermite-Gauss transverse spatial modes are presented. Due to the inherent phase stability of this type of interferometer, it provides a promising tool for the manipulation of higher order transverse spatial modes for the purposes of quantum information processing. We propose two such applications: the production of both spatial-mode entangled Bell states and heralded single photons, tailored to cover the entire Poincaré sphere of first-order transverse modes. In addition to the aforementioned transverse spatial manipulation based on free-space parity sorting, we introduce several more such techniques involving photons propagating in optical fibers. We show that when a photon propagates in a cylindrically symmetric waveguide, its spin angular momentum and its orbital angular momentum (OAM) interact. This spin-orbit interaction (SOI) leads to the prediction of several novel rotational effects: the spatial or time evolution of the photonic polarization vector is controlled by its OAM quantum number or, conversely, its spatial wave function is controlled by its spin. We demonstrate how these phenomena can be used to reversibly transfer entanglement between the spin and OAM degrees of freedom of two-particle states. In order to provide a deeper insight into the cause of the SOI for photons, we also investigate an analogous interaction for electrons in a cylindrical waveguide and find that each of the SOI effects mentioned above remain manifest for the electron case. We show that the SOI dynamics are quantitatively described by a single expression applying to both electrons and photons and explain their common origin in terms of a universal geometric phase associated with the interplay between either particle's spin and OAM. This implies that these SOI-based effects occur for any particle with spin and thereby exist independently of whether or not the particle has mass, charge, or magnetic moment. / Committee in charge: Daniel Steck, Chairperson, Physics; Michael Raymer, Member, Physics; Jens Noeckel, Member, Physics; Steven van Enk, Member, Physics; Andrew Marcus, Outside Member, Chemistry
6

Electron spin resonance in a 2D system at a GaN/AlGaN heterojunction

Shchepetilnikov, A. V., Frolov, D. D., Solovyev, V. V., Nefyodov, Yu. A., Großer, A., Mikolajick, T., Schmult, S., Kukushkin, I. V. 23 June 2022 (has links)
Spin resonance of a two-dimensional electron system confined in a GaN/AlGaN heterostructure grown by molecular beam epitaxy was resistively detected over a wide range of magnetic field and microwave frequency. Although the spin-orbit interaction is strong in this type of heterostructure at zero magnetic field, surprisingly the width of the detected spin resonance line was very narrow—down to 6.5 mT at 13.3 T. The spin depolarization time extracted from the resonance linewidth was estimated to be 2 ns. The electron g-factor was measured with high accuracy, resembling a value close to the free-electron value and its dependence on the magnetic field was studied.
7

Electronic and Spin Transport in Dirac-Like Systems

Asmar, Mahmoud M. 17 September 2015 (has links)
No description available.
8

Reduced dimensionality quantum dynamics of chemical reactions

Remmert, Sarah M. January 2011 (has links)
In this thesis a reduced dimensionality quantum scattering model is applied to the study of polyatomic reactions of type X + CH4 <--> XH + CH3. Two dimensional quantum scattering of the symmetric hydrogen exchange reaction CH3+CH4 <--> CH4+CH3 is performed on an 18-parameter double-Morse analytical function derived from ab initio calculations at the CCSD(T)/cc-pVTZ//MP2/cc-pVTZ level of theory. Spectator mode motion is approximately treated via inclusion of curvilinear or rectilinear projected zero-point energies in the potential surface. The close-coupled equations are solved using R-matrix propagation. The state-to-state probabilities and integral and differential cross sections show the reaction to be primarily vibrationally adiabatic and backwards scattered. Quantum properties such as heavy-light-heavy oscillating reactivity and resonance features significantly influence the reaction dynamics. Deuterium substitution at the primary site is the dominant kinetic isotope effect. Thermal rate constants are in excellent agreement with experiment. The method is also applied to the study of electronically nonadiabatic transitions in the CH3 + HCl <--> CH4 + Cl(2PJ) reaction. Electrovibrational basis sets are used to construct the close-coupled equations, which are solved via Rmatrix propagation using a system of three potential energy surfaces coupled by spin-orbit interaction. Ground and excited electronic surfaces are developed using a 29-parameter double-Morse function with ab initio data at the CCSD(T)/ccpV( Q+d)Z-dk//MP2/cc-pV(T+d)Z-dk level of theory, and with basis set extrapolated data, both corrected via curvilinear projected spectator zero-point energies. Coupling surfaces are developed by fitting MCSCF/cc-pV(T+d)Z-dk ab initio spin orbit constants to 8-parameter functions. Scattering calculations are performed for the ground adiabatic and coupled surface models, and reaction probabilities, thermal rate constants and integral and differential cross sections are presented. Thermal rate constants on the basis set extrapolated surface are in excellent agreement with experiment. Characterisation of electronically nonadiabatic nonreactive and reactive transitions indicate the close correlation between vibrational excitation and nonadiabatic transition. A model for comparing the nonadiabatic cross section branching ratio to experiment is discussed.

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