Chiral Green's Functions in Superconformal Field Theory

By solving the Ward identities in a superconformal field theory we find the unique three-point Green's functions composed of chiral superfields for N = 1,2,3,4 supersymmetry. We show that the N=1 four-point function with R-charge equal to one is uniquely determined by the Ward identities up to the specification of four constants. We discuss why chiral Green's functions above three-points, with total R-charge greater than N, are not uniquely determined.Comment: 32 pages, no figures, LaTeX2e forma

A Modified Stern-Gerlach Experiment Using a Quantum Two-State Magnetic Field

The Stern-Gerlach experiment has played an important role in our understanding of quantum behavior. We propose and analyze a modified version of this experiment where the magnetic field of the detector is in a quantum superposition, which may be experimentally realized using a superconducting flux qubit. We show that if incident spin-$1/2$ particles couple with the two-state magnetic field, a discrete target distribution results that resembles the distribution in the classical Stern-Gerlach experiment. As an application of the general result, we compute the distribution for a square waveform of the incident fermion. This experimental setup allows us to establish: (1) the quantization of the intrinsic angular momentum of a spin-$1/2$ particle, and (2) a correlation between EPR pairs leading to nonlocality, without necessarily collapsing the particle's spin wavefunction.Comment: 12 pages, 2 figure

Very Extended E8E_8 and A8A_8 at low levels, Gravity and Supergravity

We define a level for a large class of Lorentzian Kac-Moody algebras. Using this we find the representation content of very extended $A_{D-3}$ and $E_8$ (i.e. $E_{11}$) at low levels in terms of $A_{D-1}$ and $A_{10}$ representations respectively. The results are consistent with the conjectured very extended $A_8$ and $E_{11}$ symmetries of gravity and maximal supergravity theories given respectively in hep-th/0104081 and hep-th/0107209. We explain how these results provided further evidence for these conjectures.Comment: 16 pages, plain tex (equation 3.3 modified and one reference expanded

The subdivision and zonation of interglacial periods

Es wird immer schwieriger, vergleichende Studien über die zahlreichen Pollendiagramme eines Interglazials innerhalb Nordwesteuropas oder aber verschiedener Interglaziale dieses Raumes zu machen, und zwar wegen der Mannigfaltigkeit der Zonierungssysteme, die die einzelnen Autoren anwenden. Dennoch haben aber Iversen (1958) und Andersen (1966) gezeigt, daß in jedem der bisher untersuchten Interglaziale ähnliche Zyklen der Vegetationsentwicklung und der Bodenbildung abgelaufen sind. Die Verfasser legen dar, daß in jeder Interglazialzeit 4 Perioden der Vegetationsentwicklung festgestellt werden können und daß diese als natürliche biostratigraphische Zonen angesehen werden können, basierend auf dem Charakter der Pollengemeinschaften. Diese Perioden sind: Zone I, die Pre-temperate Zone, Betula und Pinus dominieren; Zone II, die Early-temperate Zone, Vorherrschaft der Bäume des Eichenmischwaldes; Zone III, die Late-temperate Zone, in zunehmendem Maße beherrscht durch spät einwandernde wärmeliebende Bäume, wie Carpinus und Abies; Zone IV, die Post-temperate Zone, wiederum beherrscht durch boreale Bäume, wie Pinus und Betula. Diese Zonierung kann für fast alle interglazialen Pollendiagramme Nordwesteuropas verwandt werden. Geringe Veränderungen der Vegetation, und zwar regional, lokal oder seral, können als Unterzonen beschrieben werden, ohne die Hauptzüge und den Zweck dieses Zonierungssystems zu stören.researc

Generalised Space-time and Gauge Transformations

We consider the generalised space-time introduced by the author in 2003 in the context of the non-linear realisation of the semi-direct product of E11 and its first fundamental representation. For all the fields we propose gauge transformations which are compatible with the underlying E11 structure. A crucial role is played by the generalised vielbein that the generalised space-time possess. We work out the explicit form of the gauge transformations, at low levels, in four, five and eleven dimensions.Comment: 33 page

Current-induced nuclear-spin activation in a two-dimensional electron gas

Electrically detected nuclear magnetic resonance was studied in detail in a two-dimensional electron gas as a function of current bias and temperature. We show that applying a relatively modest dc-current bias, I_dc ~ 0.5 microAmps, can induce a re-entrant and even enhanced nuclear spin signal compared with the signal obtained under similar thermal equilibrium conditions at zero current bias. Our observations suggest that dynamic nuclear spin polarization by small current flow is possible in a two-dimensional electron gas, allowing for easy manipulation of the nuclear spin by simple switching of a dc current.Comment: 5 pages, 3 fig