The Future of low Energy Photon Experiments

"Light-shining-through-a-wall" experiments search for Weakly Interacting Sub-eV Particles (WISPs). The necessity and status of such enterprises as well as their future potential are sketched.Comment: 9 pages, 4 figures, contribution to the conference PHOTON 2009 (Hamburg, May 2009

Does too much Transparency of Central Banks Prevent Agents from Using their Private Information Efficiently?

This paper analyses in a simple global games framework welfare effects of different communication strategies of a central bank: it can either publish no more than its overall assessment of the economy or be more transparent, giving detailed reasons for this assessment. The latter strategy is shown to be superior because it enables agents to use private information and to be less dependent on common knowledge. This result holds true even if the strategies of agents are strategic complements, for which case it has been argued that too much transparency might induce agents to neglect their private knowledge.transparency, private information, common knowledge

Characterization of a Transition-Edge Sensor for the ALPS II Experiment

The ALPS II experiment, Any Light Particle Search II at DESY in Hamburg, will look for light (m< 10-4 eV) new fundamental bosons (e.g., axion-like particles, hidden photons and other WISPs) in the next years by the mean of a light-shining-through-the-wall setup. The ALPS II photosensor is a Transition-Edge Sensor (TES) optimized for lambda = 1064 nm photons. The detector is routinely operated at 80 mK, allowing single infrared photon detections as well as non-dispersive spectroscopy with very low background rates. The demonstrated quantum efficiency for such TES is up to 95% at lambda =1064 nm. For 1064 nm photons, the measured background rate is < 10-2 sec-1 and the intrinsic dark count rate in a dark environment was found to be of 1,0.10-4 sec-1. Latest characterization results are discussed.Comment: Contributed to the 11th Patras Workshop on Axions, WIMPs and WISPs, Zaragoza, June 22 to 26, 201

Preisniveaueffekte der Euro-Bargeldeinführung

This article gives evidence that the euro cash changeover has contributed to the increase in the price level in Germany in January 2002. It is shown that the menu costs approach can easily explain this finding. An implication of this explanation is that the changeover will have only a temporary effect on the price level.

Original Sin - Analysing Its Mechanics and a proposed Remedy in a Simple Macroeconomic Model

This paper analyses the problem of “original sin“ (the fact that the currency of an emerging market economy usually cannot be used to borrow abroad) in a simple thirdgeneration model of currency crises. The approach differs from alternative frameworks by explicitly modeling the price setting behavior of firms if prices are sticky and the future exchange rate is uncertain. Monetary policy optimally trades off effects on price competitiveness and on debt burdens of firms. It is shown that the proposal by Eichengreen and Hausmann of creating an artificial basket currency as denominator of debt is attractive as a provision against contagion.original sin, currency crises

Human Posterior Parietal Cortex Plans Where to Reach and What to Avoid

In this time-resolved functional magnetic resonance imaging (fMRI) study, we aimed to trace the neuronal correlates of covert planning processes that precede visually guided motor behavior. Specifically, we asked whether human posterior parietal cortex has prospective planning activity that can be distinguished from activity related to retrospective visual memory and attention. Although various electrophysiological studies in monkeys have demonstrated such motor planning at the level of parietal neurons, comparatively little support is provided by recent human imaging experiments. Rather, a majority of experiments highlights a role of human posterior parietal cortex in visual working memory and attention. We thus sought to establish a clear separation of visual memory and attention from processes related to the planning of goal-directed motor behaviors. To this end, we compared delayed-response tasks with identical mnemonic and attentional demands but varying degrees of motor planning. Subjects memorized multiple target locations, and in a random subset of trials targets additionally instructed (1) desired goals or (2) undesired goals for upcoming finger reaches. Compared with the memory/attention-only conditions, both latter situations led to a specific increase of preparatory fMRI activity in posterior parietal and dorsal premotor cortex. Thus, posterior parietal cortex has prospective plans for upcoming behaviors while considering both types of targets relevant for action: those to be acquired and those to be avoided

Space representation for eye movements is more contralateral in monkeys than in humans

Contralateral hemispheric representation of sensory inputs (the right visual hemifield in the left hemisphere and vice versa) is a fundamental feature of primate sensorimotor organization, in particular the visuomotor system. However, many higher-order cognitive functions in humans show an asymmetric hemispheric lateralization—e.g., right brain specialization for spatial processing—necessitating a convergence of information from both hemifields. Electrophysiological studies in monkeys and functional imaging in humans have investigated space and action representations at different stages of visuospatial processing, but the transition from contralateral to unified global spatial encoding and the relationship between these encoding schemes and functional lateralization are not fully understood. Moreover, the integration of data across monkeys and humans and elucidation of interspecies homologies is hindered, because divergent findings may reflect actual species differences or arise from discrepancies in techniques and measured signals (electrophysiology vs. imaging). Here, we directly compared spatial cue and memory representations for action planning in monkeys and humans using event-related functional MRI during a working-memory oculomotor task. In monkeys, cue and memory-delay period activity in the frontal, parietal, and temporal regions was strongly contralateral. In putative human functional homologs, the contralaterality was significantly weaker, and the asymmetry between the hemispheres was stronger. These results suggest an inverse relationship between contralaterality and lateralization and elucidate similarities and differences in human and macaque cortical circuits subserving spatial awareness and oculomotor goal-directed actions

Economic outlook for the Euro area 2003

This article reports the spring forecast of the economic development in the Eurozone, which was carried out within the European Forecasting Network. A modest rise in GDP growth from 1.2% in 2003 up to 2.1% in 2004 is expected. The current weakness in the growth experience is caused by structural factors to a large extent. In particular, labor markets are not flexible enough in most countries.

Results from the Solar Hidden Photon Search (SHIPS)

We present the results of a search for transversely polarised hidden photons (HPs) with $\sim 3$ eV energies emitted from the Sun. These hypothetical particles, known also as paraphotons or dark sector photons, are theoretically well motivated for example by string theory inspired extensions of the Standard Model. Solar HPs of sub-eV mass can convert into photons of the same energy (photon$\leftrightarrow$HP oscillations are similar to neutrino flavour oscillations). At SHIPS this would take place inside a long light-tight high-vacuum tube, which tracks the Sun. The generated photons would then be focused into a low-noise photomultiplier at the far end of the tube. Our analysis of 330 h of data (and {330 h} of background characterisation) reveals no signal of photons from solar hidden photon conversion. We estimate the rate of newly generated photons due to this conversion to be smaller than 25 mHz/m$^2$ at the 95$$ C.L. Using this and a recent model of solar HP emission, we set stringent constraints on $\chi$, the coupling constant between HPs and photons, as a function of the HP mass