Sökning: "S-matrix"
Visar resultat 1 - 5 av 6 avhandlingar innehållade ordet S-matrix.
1. On string integrability : A journey through the two-dimensional hidden symmetries in the AdS/CFT dualities
Sammanfattning : One of the main topics in the modern String Theory are the conjectured string/gauge (AdS/CFT) dualities. Proving such conjectures is extremely difficult since the gauge and string theory perturbative regimes do not overlap. In this perspective, the discovery of infinitely many conserved charges, i.e. LÄS MER
2. Ways of determining and characterising resonances in scattering processes
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
3. Nucleon-Nucleon Scattering in a Wave-Packet Formalism
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. Study of Mutual Coupling in Finite Antenna Arrays for Massive MIMO Applications
Sammanfattning : This thesis focuses on the study of mutual coupling (MC) in finite antenna arrays for base station antennas (BSAs) for Massive multiple-input multiple-output (MIMO) applications, with an emphasis on the development of a computationally-efficient modeling technique for the analysis of MC which can be readily applied in the design or synthesis schemes for BSAs. Traditionally, the effects of MC have been ignored or underestimated in the analyses performed within the information-theoretic-based communities by assuming idealized antenna elements with no MC between them or by considering the fictitious isotropic radiator models. LÄS MER
5. Finite Energy Electronic Correlationsin Low-Dimensional Systems
Sammanfattning : This thesis report deals with the 1D Hubbard model and the quantum objects that diagonalize the normal ordered Hubbard hamiltonian, among those the so called PseudoFermions (PFs). These PFs have no residual energy interactions, are eta-spin and spin zero objects, and are the scatterers and the scattering centers of the theory. LÄS MER