Wer ist der beste Formel 1 Fahrer? Eine ökonometrische Talentbewertung

Who is the best Formula 1 driver? Until today it was impossible to answer this question because the observable performance of a driver depends both on his talent and the quality of his cars. In this article we separate for the first time driver talent from car quality by econometrically analyzing data for 57 years of Formula 1 racing. Our estimates also control for the number of drivers finishing, technical breakdowns and many other variables that influence race results. While Michael Schumacher is often believed to be the best driver, he is overtaken by Juan Manuel Fangio and Jim Clar

How Federalism Protects Future Generations from Today's Public Debts

From the politico-economic perspective, federalism is a protector of the present generation. But what about future generations? In federal states, Ricardian equivalence cannot be assumed to work properly, as migration between local jurisdictions undermines intergenerational redistribution based on parental altruism. However, we argue that there exists another equivalence mechanism which also works with purely selfish individuals: Public debts capitalize into property values. Jurisdictions with larger net debts exhibit, ceteris paribus, lower property prices. Debt capitalization in property values is the more pronounced the less elastic land supply is and the more mobile the other factors of production are. Therefore, capitalization is more relevant for local than for national debts, i.e. it is more pronounced in a federal than in a centralized state. Thus, federalism also becomes a protector of future generation

Superconductivity and antiferromagnetism in the two-dimensional Hubbard model: a variational study

A variational ground state of the repulsive Hubbard model on a square lattice is investigated numerically for an intermediate coupling strength (U=8t) and for moderate sizes (from 6×6 to 10×10). Our ansatz is superior to other widely used variational wave functions. The results for order parameters and correlation functions provide insight into the antiferromagnetic state at half-filling as well as strong evidence for a superconducting phase away from half-filling

Superconductivity and antiferromagnetism in the two-dimensional Hubbard model

En dépit de son apparente simplicité et bien qu’il ait déjà été intensivement étudié dans des contextes très variés, le modèle de Hubbard bidimensionnel est encore très loin d’avoir livré tous ses mystères. En particulier lorsqu’il décrit une interaction moyenne à fortement répulsive, c’est-à-dire un régime mal adapté aux méthodes perturbatives, son état fondamental est encore méconnu. La découverte en 1986 d’une phase supraconductrice chez les oxydes de cuivre (cuprates), apparaissant à relativement haute température, a encore avivé l’intérêt pour ce modèle puisqu’il pourrait décrire les propriétés étonnantes de ces matériaux à structures planaires. Lorsque la densité électronique correspond à une bande de valence demi remplie, le modèle de Hubbard est en effet connu pour rendre parfaitement compte de la phase antiferromagnétique obtenue expérimentalement chez les cuprates et il est probable qu’il en soit de même pour la phase supraconductive observée au-dessous d’une température critique, lorsque la densité électronique est modérément réduite en modifiant la composition du matériau (dopage). Si tel est le cas, cela signifie que seules les interactions électronique sont à l’origine de la supraconductivité, contrairement aux supraconducteurs conventionnels où l’interaction entre les électrons et les vibrations du réseau (phonons) est impliquée. Malheureusement, il existe pour l’heure peu de résultats indiscutables venant étayer cette hypothèse et la question est encore largement débattue. Dans cette thèse, la méthode variationelle est mise à profit pour tenter d’apporter une réponse claire concernant la possibilité d’un état fondamental supraconducteur pour le modèle de Hubbard répulsif. Bien que la fiabilité de ses résultats soit conditionnée par le choix d’une fonction variationelle adéquate, cette méthode est tout spécialement adaptée au régime approprié pour les cuprates, c’est-à-dire à une interaction intermédiaire. L’optimisation d’une fonction variationelle élaborée permet d’approcher de très près l’état fondamental exact, ce qui n’était pas le cas des fonctions variationelles connues jusqu’ici. En fait, la considération de petits systèmes rend accessible une solution exacte, qui indique que l’erreur commise dans notre calcul est trop faible pour influencer qualitativement nos résultats. Ceux-ci montrent qu’une phase antiferromagnétique est favorable au demi remplissage et d’une phase supraconductrice émerge lorsque la densité électronique diminue, avec un paramètre d’ordre possédant une symétrie onde-d. Toutes les caractéristiques principales propres aux oxydes de cuivre sont donc retrouvées pour l’état fondamental variationel du modèle de Hubbard répulsif. Des similitudes remarquables sont aussi observées au niveau quantitatif lorsque les propriétés de cet état fondamental sont comparées aux données expérimentales obtenues pour les cuprates.Despite its apparent simplicity and even if it has been studied intensively in various contexts, the two-dimensional Hubbard model is not yet completely understood. In particular when it describes a system with an intermediate interaction, out of range for perturbative methods, its ground state is still not well known. The discovery in 1986 of a superconducting phase in the copper oxides (cuprates), which appears at rather high temperature, has further enhanced the interest for this model, as it may describe the amazing poperties of these layered materials. Indeed, when the electronic density corresponds to a half-filled band, the Hubbard model is known to nicely account for the antiferromagnetic phase obtained experimentally for the cuprates and it is possible, as first proposed by P. W. Anderson, that it describes equally well the superconducting phase observed below a critical temperature, when the electronic density is moderatly reduced by modifying the compound composition (doping). In this case, the superconductivity originates from purely electronic interactions, contrary to conventional superconductivity where the interaction between electrons and lattice vibrations (phonons) is involved. Unfortunately, very few stringent results are available in order to support this statement and this question is still largely debated. In this thesis, the variational method is used in order to scrutinize the possibility of a superconducting ground state for the repulsive Hubbard model. Although its reliability is based on the adequate choice of the variational wave function, this method is especially suited for treating intermediate interactions, which is the appropriate regime of the cuprates. The optimization of a refined wave function allows us to obtain a variational ground state which is much closer to the exact ground state than those obtained so far using less elaborate wave functions. Actually, the exact study of small systems indicates that the error of our calculation is too small to allow for a qualitatively different behavior. Our results show that an antiferromagnetic phase is dominant at half-filling, while a superconducting phase with a d-wave symmetry of the order parameter emerges at moderate doping. The key features of the copper oxides are therefore found in the variational ground state of the repulsive Hubbard model. Some amazing similarities are also observed at the quantitative level when the properties of this ground state are compared to the experimental data obtained for the cuprates

Superconducting ground state of the two-dimensional Hubbard model: a variational study

A trial wave function is proposed for studying the instability of the two-dimensional Hubbard model with respect to d-wave superconductivity. Double occupancy is reduced in a similar way as in previous variational studies, but in addition our wave function both enhances the delocalization of holes and induces a kinetic exchange between the electron spins. These refinements lead to a large energy gain, while the pairing appears to be weakly affected by the additional term in the variational wave function.Comment: 2 pages, 1 figure, Proceedings of the M2S-HTSC-VII

District magnitude and representation of the majority's preferences—a reply and new perspectives

We reply to the comment of John Carey and Simon Hix on our original contribution entitled "District Magnitude and Representation of the Majority's Preferences: Quasi-Experimental Evidence from Popular and Parliamentary Votes” in Public Choice 151:585-610 (2012). District magnitude does not necessarily affect deviations between political representatives and their district voters in a strictly monotonic way but monotonicity is upheld for deviations between representatives and the national majority. We provide new perspectives and caution against evaluating electoral systems by focusing on individual politicians' behavior but neglecting aggregation effect

District magnitude and representation of the majority's preferences: Evidence from popular and parliamentary votes

Representatives have more effective incentives to cater to the preferences of the majority of citizens when they are elected in districts with few rather than many seats. We investigate this hypothesis empirically by matching Swiss members of parliament's voting behavior on legislative proposals with real referendum outcomes on the same issues for the years 1996 to 2008. We thus identify the impact of district magnitude on representatives' incentives to adhere to citizens' revealed preferences. We find systematic, statistically significant and economically relevant evidence that individual representatives from districts with few seats vote more often in line with majority preference

A comparative analysis of the voting behavior of constituents and their representatives for public debts

We explore the quality of political representation of constituents' preferences for budgetary decisions within a quasi-experimental setting. In the Swiss referendum process, constituents reveal their preferences for budgetary proposals which are either expected to increase or decrease public debts. We match individual politicians' voting behavior on debt increasing and debt reducing legislative proposals with eight real referendum decisions on exactly the same issues from 2008 to 2011. Thereby, we directly explore deviations of politicians from constituents' preferences with respect to budgetary policie

Full Transparency of Politicians' Actions Does Not Increase the Quality of Political Representation

We identify the impact of transparency in political decision-making on the quality of political representation with a difference-in-difference strategy. The quality of political representation is measured by the observed divergence of parliamentary decisions from revealed voter preferences on identical issues. We show that full transparency of votes of individual politicians does not decrease divergence from voter preference

‘In the interest of your bank and our country’: two encounters between China and the International Chamber of Commerce

This article examines China’s path to joining the International Chamber of Commerce (ICC), a private international organization founded in Paris in 1920, of which China was a member from 1931–1949 and from 1994 onwards. The article charts the actors and debates behind two meaningful encounters. The first took place while the Nanjing government was raising funds for economic reconstruction, and the ICC aimed to mediate China’s fundraising efforts through private multilateral channels. The second was in the 1980s, when the People’s Republic was seeking to enter the world trade system. ICC members acted as educators and facilitators of world trade practicalities for the People’s Republic, which eventually rejoined the ICC in 1994. The article draws on Chinese, European, and American source material collected from governments, chambers of commerce, and private businessmen to make a twofold contribution. First, it adds nuance to the narrative of China’s economic internationalization by identifying an important non-governmental diplomatic channel. Second, it questions the ICC’s self-proclaimed identity as a non-political economic organization by showing how the political was indissociable from the economic when it came to China’s membership