Am 10. April findet im HS 05.12 ab 14:00 ein Workshop zum Thema stochastischer Methoden statt.
Der genaue Zeitplan für diese Veranstaltung:
14:00 Volker Springel (Heidelberg University and Heidelberger Institute for Theoretical Studies (HITS))
Simulating the Universe
I review the techniques and basic results of cosmological simulations of structure formation based on the N-body technique, which effectively is a Monte-Carlo integration of the collisionless Vlasov-Boltzmann equations.I also focus on hydrodynamical simulation techniques in cosmology and on ultra-large N-body simulations. In particular, I describe a novel moving-mesh methodology for gas dynamics in which a fully dynamic and adaptive Voronoi tessellation is used to formulate a finite volume discretization of hydrodynamics which offers numerous advantages compared with traditional techniques. I will also dicuss some results from the Millennium-XXL simulation, the largest high-resolution cosmological N-body simulation carried out to date, and illustrate how the most extreme galaxy clusters found therein constrain cosmology.
15:00 Christoph Dellago(Univ. Wien)
Nucleation at the nanoscale: pathways of phase transitions in small systems
Under suitable conditions, first order phase transitions such as the freezing of a liquid or the structural transformation of a solid occur via a nucleation and growth mechanism, in which a nucleus of the stable phase is formed in the metastable phase. For systems with sizes in the nanometer regime, the nucleation mechanism and its kinetics are strongly affected by finite size effects.I will address this issue using melting/freezing of gold nanoparticles, the Wurtzite-to-rock salt transition in CdSe nanocrystals and the magnetization reversal in a finite Ising model as illustrative examples. Based on the results of transition path sampling simulations, I provide a picture of the transition mechanism paying particular attention to the structure of the critical nuclei.The role of the reaction coordinate in the investigation of the transition mechanism is discussed.
16:00 Coffee break
16:30 Stefan Schaefer(CERN)
Strategies for Quantum Chromodynamics (QCD) on the lattice
Numerical simulations of Quantum Chromodynamics have become more realistic during recent years. This is due to significant progress in the algorithms used in the computations, mainly due to a better understanding of the system we simulate.After an introduction to the concepts and the general algorithmic approach of lattice QCD calculations, the talk will highlight some of the ideas which have driven recent developments. Insights from considering the simulation itself as a physical system will play a central role.
