Proposal for an interference experiment to test the applicability of quantum theory to event-based processes

We analyze a single-particle Mach-Zehnder interferometer experiment in which the path length of one arm may change (randomly or systematically) according to the value of an external two-valued variable $x$, for each passage of a particle through the interferometer. Quantum theory predicts an interference pattern that is independent of the sequence of the values of $x$. On the other hand, corpuscular models that reproduce the results of quantum optics experiments carried out up to this date show a reduced visibility and a shift of the interference pattern depending on the details of the sequence of the values of $x$. The proposed experiment will show that: (1) it can be described by quantum theory, and thus not by the current corpuscular models, or (2) it cannot be described by quantum theory but can be described by the corpuscular models or variations thereof, or (3) it can neither be described by quantum theory nor by corpuscular models. Therefore, the proposed experiment can be used to determine to what extent quantum theory provides a description of observed events beyond the usual statistical level.Comment: Accepted for publication in J. Phys. Soc. Jp

Scanning the Topological Sectors of the QCD Vacuum with Hybrid Monte Carlo

We address a long standing issue and determine the decorrelation efficiency of the Hybrid Monte Carlo algorithm (HMC), for full QCD with Wilson fermions, with respect to vacuum topology. On the basis of five state-of-the art QCD vacuum field ensembles (with 3000 to 5000 trajectories each and m_pi/m_rho-ratios in the regime >0.56, for two sea quark flavours) we are able to establish, for the first time, that HMC provides sufficient tunneling between the different topological sectors of QCD. This will have an important bearing on the prospect to determine, by lattice techniques, the topological susceptibility of the vacuum, and topology sensitive quantities like the spin content of the proton, or the eta' mass.Comment: 5 pages, 4 eps-figure

Decorrelating Topology with HMC

The investigation of the decorrelation efficiency of the HMC algorithm with respect to vacuum topology is a prerequisite for trustworthy full QCD simulations, in particular for the computation of topology sensitive quantities. We demonstrate that for mpi/mrho ratios <= 0.69 sufficient tunneling between the topological sectors can be achieved, for two flavours of dynamical Wilson fermions close to the scaling region beta=5.6. Our results are based on time series of length 5000 trajectories.Comment: change of comments: LATTICE98(confine

Die Bestimmungsgründe der räumlichen Verteilung des ökologischen Landbaus in Deutschland

Die Bestimmungsgründe der räumlichen Verteilung des ökologischen Landbaus sind nicht eindeutig geklärt. Daher werden verschiedene Faktoren hinsichtlich ihres Einflusses auf den Flächenanteil und die regionale Verteilung des ökologischen Landbaus in Deutschland untersucht. In diesem Beitrag werden erste und in einigen Punkten noch vorläufige Ergebnisse eines laufenden Forschungsprojektes dargestellt

The Quest for Light Sea Quarks: Algorithms for the Future

As part of a systematic algorithm study, we present first results on a performance comparison between a multibosonic algorithm and the hybrid Monte Carlo algorithm as employed by the SESAM collaboration. The standard Wilson fermion action is used on 32*16^3 lattices at beta=5.5.Comment: LaTeX, 3 pages, Lattice2001(algorithms

The influence of lithium excess in the target on the properties andcompositions of Li1+ x Mn2O4− δ thin films prepared by PLD

Li-Mn-O thin films were deposited by pulsed laser deposition (PLD) onto stainless steel substrates using targets containing different concentrations of added Li2O. The influence of the target composition on the stoichiometry of the resulting thin films, the surface morphology and the electrochemical properties was studied. The application of the target with added 7.5 mol% Li2O results in an almost ideal lithium content, while all films were still oxygen deficient. The thin films were applied as electrodes in Li//Li1+x Mn2O4−δ cells (i.e. model cells for a rechargeable Li-ion battery) and characterized by cyclic voltammetry and galvanostatic charge/discharge experiments. The electrochemical measurements of the thin films confirmed that the thin films can serve as good model systems and that they show a sufficient cyclabilit

Multicanonical Hybrid Monte Carlo: Boosting Simulations of Compact QED

We demonstrate that substantial progress can be achieved in the study of the phase structure of 4-dimensional compact QED by a joint use of hybrid Monte Carlo and multicanonical algorithms, through an efficient parallel implementation. This is borne out by the observation of considerable speedup of tunnelling between the metastable states, close to the phase transition, on the Wilson line. We estimate that the creation of adequate samples (with order 100 flip-flops) becomes a matter of half a year's runtime at 2 Gflops sustained performance for lattices of size up to 24^4.Comment: 15 pages, 8 figure

Temperature dependence of instantons in QCD

We investigate the temperature dependence of the instanton contents of gluon fields, using unquenched lattice QCD and the cooling method. The instanton size parameter deduced from the correlation function decreases from 0.44fm below the phase-transition temperature $T_c$ ($\approx 150$MeV) to 0.33fm at 1.3 $T_c$. The instanton charge distribution is Poissonian above $T_c$, but it deviates from the convoluted Poisson at low temperature. The topological susceptibility decreases rapidly below $T_c$, showing the apparent restoration of the $U(1)_A$ symmetry already at $T \approx T_c$.Comment: 8 pages TEX, 3 Postscript figures available at http://www.krl.caltech.edu/preprints/MAP.htm