Emergence of classical reality from a quantum mechanical background

A model for the process of knowledge acquisition is presented that shows how naive realism emerges from a quantum mechanical background. We formalise this process of emergence and obtain in this way an illustrative insight to some of the most fundamental physical theories: GRW-theory and E^∞-theory.     

Simulations of polyelectrolyte dynamics in an externally applied electric field in confined geometry

We consider the dynamics of charged polymers in free solution in a slit geometry under the influence of an electrical field, applied at an angle to the plane parallel walls of the confinement. The simulations are carried out using the Brownian dynamics method with explicit counterions and implicit hydrodynamics. The hydrodynamic interactions between all the particles and the plane parallel walls are taken into account using a diffusion matrix which depends on slit geometry and the actual polyelectrolyte-solute conformations. We observe a selective transport of the charged polymers, as a function of the degree of polymerization and slit height.     

A Geometric Framework for Stochastic Shape Analysis

We introduce a stochastic model of diffeomorphisms, whose action on a variety of data types descends to stochastic evolution of shapes, images and landmarks. The stochasticity is introduced in the vector field which transports the data in the large deformation diffeomorphic metric mapping framework for shape analysis and image registration. The stochasticity thereby models errors or uncertainties of the flow in following the prescribed deformation velocity. The approach is illustrated in the example of finite-dimensional landmark manifolds, whose stochastic evolution is studied both via the Fokker–Planck equation and by numerical simulations. We derive two approaches for inferring parameters of the stochastic model from landmark configurations observed at discrete time points. The first of the two approaches matches moments of the Fokker–Planck equation to sample moments of the data, while the second approach employs an expectation-maximization based algorithm using a Monte Carlo bridge sampling scheme to optimise the data likelihood. We derive and numerically test the ability of the two approaches to infer the spatial correlation length of the underlying noise.

     

Chemistry of 3-arylindenones: behavior in superacids and photodimerization

In superacids HSO₃F and CF₃SO₃H, it has been found that 3-arylindenones are very stable and exist as a doubly protonated species. NMR showed protonation both at the oxygen of the carbonyl group and at the C2 carbon of the indenone system. 3-Arylindenones proved however very sensitive to heat and light. Their [2+2] photodimerization under daylight has been studied.     

Resonant and nonresonant contributions from unphysical regions in dispersion relations

Unphysical regions on the right hand cut in partial wave dispersion relations for a two-particle processA+B→A′+B′ are expressed by measurable quantities, under the assumption that there is only one important 2-particle channel in the unphysical region. The solution is unique, if the phase shiftδ _l for the elastic scattering in the channel responsible for the appearance of the unphysical region takes a value between 0 andπ at the physical threshold forA+B→A′+B′. The difference between non resonant (δ_l≠π/2 in the unphysical region) and resonant contributions is shortly discussed.     

Palladium

Ohne Zusammenfassung