Sökning: "low-energy modes"

Visar resultat 1 - 5 av 13 avhandlingar innehållade orden low-energy modes.

1. 1. Low-Energy Modes of Molecules and Atoms Chemisorbed on a Metal Surface. CO and O on Pt(111) Studied by Infrared Spectroscopy

   Författare :Ulrika Engström; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; dipole-allowed modes; low-energy modes; carbon monoxide; Infrared spectroscopy; dipole-forbidden modes; Pt 111 ; anti-absorption; Fermi resonance; atomic oxygen;

   Sammanfattning : This thesis is devoted to the investigation of low-energy metal-adsorbate vibrational modes of CO molecules and O atoms chemisorbed on a Pt(111) surface using infrared spectroscopy (IRS). The infrared selection rule states that only vibrational modes having a non-vanishing component of its dynamical dipole moment perpendicular to the surface can be directly excited using IRS, known as dipole-allowed modes. LÄS MER

3. 2. Theoretical studies of lattice- and spin-polarons

   Författare :Nina Bondarenko; Olle Eriksson; Natalia Skorodumova; Manuel Pereiro; Maria Roser Valenti Vall; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Polaron; Nonlinear Schrödinger Equation; Nonlocality; Solitons; Integrable systems; Quantum field theory low energy ; Electron-phonon interaction; Density functional theory; Electronic structure of atoms and molecules; Spin-polaron; Langevin equation; Transport properties; Hubbard model; Heisenberg lattice; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

   Sammanfattning : Theoretical studies of lattice- and spin-polarons are presented in this thesis, where the primary tool is ab-initio electronic structure calculations. The studies are performed with employment of a variety of analytical and computational methods. LÄS MER

4. 3. Modelling, failure modes prediction and optimization of gear shifting mechanism, Application to heavy vehicle transmission systems

   Författare :Muhammad Irfan; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; failure modes prediction.; gear shifting; GT-Suite modelling; optimization; Synchronizer; constrained Lagrangian formalism; sensitivity analysis;

   Sammanfattning : The transmission system has a key role to drive a vehicle transmitting power from engine to rotational motion at wheels. Gear shifting mechanism inside the gearbox is a crucial part of the transmission system. LÄS MER

5. 4. Collective Electron Dynamics in Mesoscopic Systems

   Författare :Oleksandr Zazunov; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Andreev reflection; Josephson effect; qubit; composite fermions; Andreev levels; resonant tunneling; superconductivity; high-T c superconductors; quantum point contact; fractional quantum Hall effect;

   Sammanfattning : This work is devoted to a theoretical investigation of collective electron dynamics in low dimensional materials and mesoscopic structures. A common feature of these studies is the focus on the properties of the low energy dynamics of conduction electrons. One class of studied materials is the high-Tc superconductor Nd2CuO4 and related compounds. LÄS MER

7. 5. Exploring effective descriptions of gauge fields and strings : A Lagrangian approach with insights from color-kinematics duality

   Författare :Lucia M. Garozzo; Henrik Johansson; Chris White; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; scattering amplitudes; double copy; gauge theory; string theory; Theoretical Physics; Teoretisk fysik;

   Sammanfattning : The concept of a color-kinematics duality is an important driving force in advancing the modern understanding of scattering amplitudes, in both field theory and string theory. Yet, open questions remain that motivate the need for a deeper understanding of the duality. LÄS MER