Search for dissertations about: "critical exponents"

Showing result 1 - 5 of 20 swedish dissertations containing the words critical exponents.

2. 1. Critical Phenomena and Exchange Coupling in Magnetic Heterostructures

   Author : Martina Ahlberg; Gabriella Andersson; Björgvin Hjörvarsson; Steve Bramwell; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; phase transitions; critical behavior; 2D XY model; MOKE; magnetic thin films and superlattices; amorphous multilayers; magnetic proximity effects; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

   Abstract : The continuous phase transition in thin magnetic films and superlattices has been studied using the magneto-optical Kerr effect (MOKE) and polarized neutron scattering (PNR).  It has been shown that the critical behavior of amorphous thin films belonging to the 2D XY universality class can be described within the same theory as crystalline sample. READ MORE

4. 2. Jamming and Soft-Core Rheology

   Author : Daniel Vågberg; Peter Olsson; Teitel Stephen; Vitelli Vincenzo; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; jamming; rheology; soft matter; granular material; SLLOD; critical point; critical scaling;

   Abstract : Many different physical systems, such as granular materials, colloids, foams and emulsions exhibit a jamming transition where the system changes from a liquid-like flowing state to a solid jammed state as the packing fraction increases. These systems are often modeled using soft-core particles with repulsive contact forces. READ MORE

5. 3. Characteristic properties of two-dimensional superconductors close to the phase transition in zero magnetic field

   Author : Kateryna Medvedyeva; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Physics; Fysik; superconductor; two dimensions; phase transition; vortex; currentvoltage characteristics; complex conductivity; scaling; critical exponents; XY-type models; dynamics; Physics; Fysik; fysik; Physics;

   Abstract : The main focus of this thesis lies on the critical properties of twodimensional (2D) superconductors in zero magnetic field. Simulations based on variants of the 2D XY model are shown to give characteristic features close to the phase transition which agree qualitatively with experimental data. READ MORE

6. 4. Phase transitions in novel superfluids and systems with correlated disorder

   Author : Hannes Meier; Mats Wallin; Asle Sudbø; KTH; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; condensed matter physics; phase transitions; critical phenomena; spin models; quantum phase transitions; quantum fluids; superfluidity; superconductivity; disordered systems; Bose glass; dirty bosons; vortex pinning; statistical mechanics; Monte Carlo simulation; Wolff algorithm; classical worm algorithm; Wang-Landau algorithm; Fysik; Physics;

   Abstract : 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. READ MORE

7. 5. Gibbs Measures and Phase Transitions in Potts and Beach Models

   Author : Per Hallberg; KTH; []
   Keywords : Potts model; beach model; percolation; random-cluster model; Gibbs measure; coupling; Markov chains on infinite trees; critical exponent;

   Abstract : The theory of Gibbs measures belongs to the borderlandbetween statistical mechanics and probability theory. In thiscontext, the physical phenomenon of phase transitioncorresponds to the mathematical concept of non-uniqueness for acertain type of probability measures.The most studied model in statistical mechanics is thecelebrated Ising model. READ MORE