Spin dynamics of an ultra-small nanoscale molecular magnet

We present mathematical transformations which allow us to calculate the spin dynamics of an ultra-small nanoscale molecular magnet consisting of a dimer system of classical (high) Heisenberg spins. We derive exact analytic expressions (in integral form) for the time-dependent spin autocorrelation function and several other quantities. The properties of the time-dependent spin autocorrelation function in terms of various coupling parameters and temperature are discussed in detail

Collective excitations in quantum Hall liquid crystals: Single-mode approximation calculations

A variety of recent experiments probing the low-temperature transport properties of quantum Hall systems have suggested an interpretation in terms of liquid crystalline mesophases dubbed {\em quantum Hall liquid crystals}. The single mode approximation (SMA) has been a useful tool for the determination of the excitation spectra of various systems such as phonons in $^4$He and in the fractional quantum Hall effect. In this paper we calculate (via the SMA) the spectrum of collective excitations in a quantum Hall liquid crystal by considering {\em nematic}, {\em tetratic}, and {\em hexatic} generalizations of Laughlin's trial wave function having two-, four- and six-fold broken rotational symmetry, respectively. In the limit of zero wavevector \qq the dispersion of these modes is singular, with a gap that is dependent on the direction along which \qq=0 is approached for {\em nematic} and {\em tetratic} liquid crystalline states, but remains regular in the {\em hexatic} state, as permitted by the fourth order wavevector dependence of the (projected) oscillator strength and static structure factor.Comment: 6 pages, 5 eps figures include

\u3csup\u3e4\u3c/sup\u3eHe Shadow Wave Function with an Inverse Seventh Power Particle-Particle Correlation Function

Many ground state studies of 4He using a shadow wave function with an inverse fifth power McMillan particle-particle correlation function have yielded radial distribution functions with misplaced peaks. It has been conjectured that this is due to the specific choice of the McMillan correlation function. However, beyond the use of fully optimized two-particle correlation functions, there has been little study of simple alternatives that can correct this defect. In this work we show that the remedy is surprisingly simple. When a shadow wave function with an inverse seventh power particle-particle correlation function is used to study 4He, it gives a correctly peaked radial distribution function, lowers the energy at all liquid and solid densities, and produces an excellent equation of state

\u3csup\u3e4\u3c/sup\u3eHe Shadow Wave Function with an Inverse Seventh Power Particle-Particle Correlation Function

Many ground state studies of 4He using a shadow wave function with an inverse fifth power McMillan particle-particle correlation function have yielded radial distribution functions with misplaced peaks. It has been conjectured that this is due to the specific choice of the McMillan correlation function. However, beyond the use of fully optimized two-particle correlation functions, there has been little study of simple alternatives that can correct this defect. In this work we show that the remedy is surprisingly simple. When a shadow wave function with an inverse seventh power particle-particle correlation function is used to study 4He, it gives a correctly peaked radial distribution function, lowers the energy at all liquid and solid densities, and produces an excellent equation of state

Multicrystalline silicon ingot crystallisation from reusable crucibles

This presentation was part of the Workshop: Recycling, reuse and resource efficiency: New solutions for a PV circular economy - Results from the projects CABRISS and ECOSOLAR. The workshop was organized within Freiberg Silicon Days 2017

Genetically engineered polypeptides as a new tool for inorganic nano-particles separation in water based media

The present paper relates a method for the separation of an insoluble inorganic powder out of a mixture of several insoluble powders with different chemical compositions, using genetically engineered inorganic binding peptides (GEPI). GEPI are small peptides that recognize and specifically bind an inorganic solid material. This GEPI is anchored to magnetic beads for easy recovery of the powder of interest from the mixture.Biocoa