Sökning: "scattering matrix"

Visar resultat 21 - 25 av 138 avhandlingar innehållade orden scattering matrix.

1. 21. Modelling of Quantum Transport in Nanostructures

   Författare :Dan Csontos; Fasta tillståndets fysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; ballistic transport; quantum wire; quantum dot; resonant tunnelling; three-terminal; disorder; Physics; Fysik; Fysicumarkivet A:2002:Csontos; scattering matrix; quantum transport;

   Sammanfattning : In this thesis, theoretical studies of the transport properties of three nanoscale systems: one-dimensional (1D) quantum wires (QWRs), zero-dimensional (0D), laterally confined, double-barrier resonant tunnelling structures (DBRTSs) and three-terminal ballistic junctions (TBJs), have been performed. In the first part of the thesis, an overview of the realization and properties of such systems is given along with a description of modelling tools used in the calculations. LÄS MER

3. 22. Nucleon-Nucleon Scattering in a Wave-Packet Formalism

   Författare :Sean Miller; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; nuclear physics; chiral potentials; two-nucleon scattering;

   Sammanfattning : In this thesis I analyse the prospect of leveraging statistical analyses of the strong nuclear interaction by using the wave-packet continuum discretisation (WPCD) method to efficiently compute nucleon-nucleon (NN) scattering observables on a graphics processing unit (GPU). The WPCD method gives approximate solutions to the S-matrix at multiple scattering energies at the cost of a single eigendecomposition of the NN channel Hamiltonian. LÄS MER

4. 23. Improving Parton Showers with Fixed Order Matrix Elements

   Författare :Stefan Prestel; Teoretisk partikelfysik - Geonomgår omorganisation; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Matrix Element Merging; Parton Shower; QCD; Phenomenology; Fysicumarkivet A:2013:Prestel;

   Sammanfattning : This thesis considers numerical simulations of high energy particle collisions, and improvements in the description of multiple collimated jets of hadrons in collision events in particular. In the event simulation software called event generators, the structure of multi-jet events is determined through an interplay of the input calculation, parton showers and phenomenological hadronisation models. LÄS MER

5. 24. Neutron Scattering Experiments and Computer Simulation Studies of a Polymer Electrolyte

   Författare :Patrik Carlsson; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; neutron scattering; reverse Monte Carlo simulation; PPO-LiClO4; poly propylene oxide ; polymer electrolytes; polymer dynamics;

   Sammanfattning : Polymer electrolytes are regarded as key components in promising new types of batteries for portable electronic devices and electric cars. Batteries for such applications require polymer electrolytes with improved properties, e.g. a higher ionic conductivity. LÄS MER

7. 25. Ways of determining and characterising resonances in scattering processes

   Författare :Ksenia Shilyaeva; Nils Elander; Dage Sundholm; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; quantum scattering theory; complex scaling; resonances; Molecular physics; Molekylfysik; fysik; Physics;

   Sammanfattning : Scattering cross sections very often display structures. To clarify if these structures correspond to resonances one has to check if they are poles of the scattering matrix (S-matrix) in the fourth quadrant of the complex momentum plane. Furthermore, the states corresponding to these poles also need to have an appropriate scattering amplitude. LÄS MER