Sökning: "classical spin models"
Visar resultat 1 - 5 av 16 avhandlingar innehållade orden classical spin models.
1. Theoretical Studies of Two-Dimensional Magnetism and Chemical Bonding
Sammanfattning : This thesis is divided into two parts. In the first part we study thermodynamics of the two-dimensional Heisenberg ferromagnet with dipolar interaction. This interaction breaks the conditions of the Mermin-Wagner theorem, resulting in a finite transition temperature. LÄS MER
2. Criticality and Frustration: Classical and Quantum Spin Models in Two Dimensions
Sammanfattning : We investigate two-dimensional spin models and begin with an introduction to critical phenomena with emphasis on classical systems with boundaries and conformal invariance. Then we introduce the antiferromagnetic quantum Heisenberg model with frustrating interactions. LÄS MER
3. Phase transitions in novel superfluids and systems with correlated disorder
Sammanfattning : Condensed matter systems undergoing phase transitions rarely allow exact solutions. The presence of disorder renders the situation even worse but collective Monte Carlo methods and parallel algorithms allow numerical descriptions. LÄS MER
4. Spectral Methods for Self-Assembly
Sammanfattning : Conventional manufacturing relies on robotics and chemistry to create, shape and combine components into products. Nature shows us an alternative route: by carefully designing interactions between components, they can be made to spontaneously self-assemble into complex arrangements. LÄS MER
5. Quantum Kinetic Theory for Plasmas : spin, exchange, and particle dispersive effects
Sammanfattning : This thesis is about developing and studying quantum mechanical models of plasmas. Quantum effects can be important at high densities, at low temperatures, and in strong electromagnetic fields, in various laboratory and astrophysical systems. LÄS MER