High-precision spectroscopy of the forbidden 2 3S1 - 2 1P1 transition in quantum degenerate metastable helium

We have measured the forbidden 2 3S1 - 2 1P1 transition at 887 nm in a quantum degenerate gas of metastable He-4 atoms confined in an optical dipole trap. The determined transition frequency is 338 133 594.4 (0.5) MHz, from which we obtain an ionization energy of the 2 1P1 state of 814 709 148.6 (0.5) MHz. This ionization energy is in disagreement by > 3 sigma with the most accurate quantum electrodynamics (QED) calculations available. Our measurements also provide a new determination of the lifetime of the 2 1P1 state of 0.551 (0.004)stat (+ 0.013,- 0.000)syst ns, which is the most accurate determination to date and in excellent agreement with theory.Comment: 10 pages, 13 figures, paper includes supplemental information. Paper submitted for revie

An ever More Polarized Union: The Greek Problem and the Failure of EU Economic Governance. CES Open Forum Series #14 2018-2019

As the Greek economy continues on its downward trajectory, the policy debate has degenerated into a re-enactment of the neoclassics versus Keynesians controversy. Yet, the Greek crisis can be solved neither by more austerity and structural reforms nor by Keynesian reflation. The core problem lies in a form of integration that has systematically weakened the Greek economy while stabilizing a clientelistic mode of interest intermediation. In order to recover, Greece needs a substantial devaluation plus an interventionist industrial policy. Yet, such a form of integration is not palatable to the North West European creditor countries, nor is it attractive to the Greek government as it would require a break with the clientelistic organization of political power while removing the scapegoat of the EU

Imperial legacy? The EU's Developmental Model and the Crisis of the European Periphery. CES Papers - Open Forum #19, 2013-2014

The high hopes for rapid convergence of Eastern and Southern EU member states are increasingly being disappointed. With the onset of the Eurocrisis convergence has given way to divergence in the southern members, and many Eastern members have made little headway in closing the development gap. The EU´s performance compares unfavourably with East Asian success cases as well as with Western Europe´s own rapid catch-up to the USA after 1945. Historical experience indicates that successful catch up requires that less-developed economies to some extent are allowed to free-ride on an open international economic order. However, the EU´s model is based on the principle of a level-playing field, which militates against such a form of economic integration. The EU´s developmental model thus contrasts with the various strategies that have enabled successful catch up of industrial latecomers. Instead the EU´s current approach is more and more reminiscent of the relations between the pre-1945 European empires and their dependent territories. One reason for this unfortunate historical continuity is that the EU appears to have become entangled in its own myths. In the EU´s own interpretation, European integration is a peace project designed to overcome the almost continuous warfare that characterised the Westphalian system. As the sovereign state is identified as the root cause of all evil, any project to curtail its room of manoeuvre must ultimately benefit the common good. Yet, the existence of a Westphalian system of nation states is a myth. Empires and not states were the dominant actors in the international system for at least the last three centuries. If anything, the dawn of the age of the sovereign state in Western Europe occurred after 1945 with the disintegration of the colonial empires and thus historically coincided with the birth of European integration

Effective inertial frame in an atom interferometric test of the equivalence principle

In an ideal test of the equivalence principle, the test masses fall in a common inertial frame. A real experiment is affected by gravity gradients, which introduce systematic errors by coupling to initial kinematic differences between the test masses. We demonstrate a method that reduces the sensitivity of a dual-species atom interferometer to initial kinematics by using a frequency shift of the mirror pulse to create an effective inertial frame for both atomic species. This suppresses the gravity-gradient-induced dependence of the differential phase on initial kinematic differences by a factor of 100 and enables a precise measurement of these differences. We realize a relative precision of $\Delta g / g \approx 6 \times 10^{-11}$ per shot, which improves on the best previous result for a dual-species atom interferometer by more than three orders of magnitude. By suppressing gravity gradient systematic errors to below one part in $10^{13}$, these results pave the way for an atomic test of the equivalence principle at an accuracy comparable with state-of-the-art classical tests.Comment: 5 pages, 4 figure

Legal-Philosophical Propositions

It is possible to write a Kelsenian ‘Legal-Philosophical Tractate’ – based on Kelsen’s Pure Theory of Law – after the example of Wittgenstein’s Tractatus Logico-Philosophicus. The following main and sub-propositions analogous to the main and sub-propositions of the Tractatus are a proof thereof and give an initial impetus to it: “May others come and do it better”. Unlike Wittgenstein’s Tractatus, that ends with the famous proposition 7 that one should be silent about what cannot be spoken, a Kelsenian Tractate would not end with an analogous main proposition, but with two sub-propositions that show the (relative) value of both ‘the speaking’ and ‘the silence’ of positive law

Spectral Analysis of Correlated One-Dimensional Systems with Impurities

An averaging procedure is proposed to account for spectral features of correlated one-dimensional systems in the presence of non-magnetic impurities. The dynamical spin structure factor for a corresponding random ensemble of Heisenberg chain segments is calculated by exact numerical diagonalization. It is shown that a few-pole approximation is sufficient to describe the numerical results. A similar analysis is proposed for the discussion of experimental spectra, such as obtained by inelastic neutron scattering measurements on Zn-doped CuO chains. By examination of the disorder-induced pseudo-gap, the loss of spectral weight, and the discrete peak structures due to smallest-cluster contributions, the underlying impurity distribution function can be determined.Comment: RevTex, 4 pages with 4 eps figure

Laboratory methods for case finding in human psittacosis outbreaks: a systematic review.

Psittacosis outbreak investigations require rapid identification of cases in order to trace possible sources and perform public health risk assessments. In recent outbreaks in the Netherlands, such investigations were hampered by the non-specificity of laboratory testing methods to identify human Chlamydia psittaci infections

Nationwide outbreak of STEC O157 infection in the Netherlands, December 2008-January 2009: continuous risk of consuming raw beef products.

The Netherlands experienced a nationwide outbreak of Shiga toxin-producing Escherichia coli (STEC) O157 with onset of symptoms from the end of December 2008 until the end of January 2009. A total of 20 laboratory-confirmed cases were linked to the outbreak strain, serotype O157: H-, stx1, stx2, eae and e-hly positive. The investigation into the source of this outbreak is still ongoing, but evidence so far suggests that infection occurred as a result of consuming contaminated raw meat (steak tartare)