Sökning: "Time dependent dynamics"

Visar resultat 1 - 5 av 343 avhandlingar innehållade orden Time dependent dynamics.

  1. 1. Substructure dynamics : In-situ annealing coupled with numerical modelling

    Författare :Verity Borthwick; Stockholms universitet; []
    Nyckelord :;

    Sammanfattning : The understanding of substructural behaviour during post-deformational annealing is key to interpreting rheological adjustments during tectonic change, and the processes which cause them. The focus of this study is to use coupled in-situ experimental techniques with numerical simulation to increase understanding of substructure dynamics in geological materials. LÄS MER

  3. 2. Ultrafast Magnetization Dynamics : Element-selective studies of magnetic alloys using ultra short XUV pulses

    Författare :Rameez Saeed Malik; Olof Karis; Uwe Bovensiepen; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; magnetization dynamics; magnetic alloys; HHG; ultrashort laser pulses; magneto-optical Kerr effect MOKE ; Gilbert damping; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

    Sammanfattning : In this thesis, I investigate the ultrafast magnetization dynamics in 3d ferromagnets and their alloys with ultrashort laser pulses. The high harmonics generation (HHG) setup provides extreme-ultraviolet photons with energies 35-72 eV, which is the energy range where 3d metals have their M2,3 absorption edges. LÄS MER

  4. 3. Linear and non-linear dynamics of non-autonomous flows

    Författare :J. Simon Kern; Dan S. Henningson; Ardeshir Hanifi; Peter J. Schmid; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Time-dependent flows; linear stability; non-linear dynamics; Floquet analysis; optimally time-dependent modes; Teknisk mekanik; Engineering Mechanics;

    Sammanfattning : Fluid flows subject to time-dependent external forces or boundary conditions are ubiquitous in biology and technical applications. Whether one considers birds flying by flapping their wings or the gust response of wind turbines, the flow is non-autonomous. LÄS MER

  5. 4. Numerical Methods for Wave Propagation : Analysis and Applications in Quantum Dynamics

    Författare :Emil Kieri; Sverker Holmgren; Vasile Gradinaru; Hans O. Karlsson; Tobias Jahnke; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; computational wave propagation; quantum dynamics; time-dependent Schrödinger equation; spectral methods; Gaussian beams; splitting methods; low-rank approximation; Scientific Computing; Beräkningsvetenskap;

    Sammanfattning : We study numerical methods for time-dependent partial differential equations describing wave propagation, primarily applied to problems in quantum dynamics governed by the time-dependent Schrödinger equation (TDSE). We consider both methods for spatial approximation and for time stepping. LÄS MER

  7. 5. Electron-Lattice Dynamics in pi-Conjugated Systems

    Författare :Magnus Hultell (Andersson); Sven Stafström; Alexander Onipko; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Polaron dynamics; Exciton dynamics; pi-conjugated systems; Su-Schrieffer-Heeger SSH model; Adiabaticity; Charge carrier transport; Organic electronics.; Computational physics; Beräkningsfysik;

    Sammanfattning : In this thesis we explore in particular the dynamics of a special type of quasi-particle in pi-conjugated materials termed polaron, the origin of which is intimately related to the strong interactions between the electronic and the vibrational degrees of freedom within these systems. In order to conduct such studies with the particular focus of each appended paper, we simultaneously solve the time-dependent Schrödinger equation and the lattice equation of motion with a three-dimensional extension of the famous Su-Schrieffer-Heeger (SSH) model Hamiltonian. LÄS MER