Mistaken Identity and Mirror Images: Albert and Carl Einstein, Leiden and Berlin, Relativity and Revolution

Albert Einstein accepted a 'special' visiting professorship at the University of Leiden in the Netherlands in February 1920. Although his appointment should have been a mere formality, it took until October of that year before Einstein could occupy his special chair. Why the delay? The explanation involves a case of mistaken identity with Carl Einstein, Dadaist art, and a particular Dutch fear of revolutions. But what revolution was one afraid of? The story of Einstein's Leiden chair throws new light on the reception of relativity and its creator in the Netherlands and in Germany

Reactionaries and Einstein's Fame: "German Scientists for the Preservation of Pure Science," Relativity, and the Bad Nauheim Meeting

Two important and unpleasant events occurred in Albert Einstein's life in 1920: That August an antirelativity rally was held in the large auditorium of the Berlin Philharmonic, and a few weeks later Einstein was drawn into a tense and highly publicized debate with Philipp Lenard on the merits of relativity at a meeting in Bad Nauheim, Germany. I review these events and discuss how they affected Einstein in light of new documentary evidence that has become available through the publication of Volume 10 of the Collected Papers of Albert Einstein.Comment: 18 page

Break it Down: An Alternative Approach to Measuring Effectiveness in Counterterrorism

This paper will review the ways in which the effectiveness of counterterrorism measures and policies has been assessed and argue that they suffer largely from the same difficulties. For many of the chosen indicators it is not clear whether they represent what they are supposed to represent and whether shifts in the scores can be attributed to counterterrorism. After having discussed these problems, a different way of measuring counterterrorism effectiveness is outlined. It rests on the assumption that counterterrorism should be broken down into separate components that should all be evaluated separately. For all components, a causal chain from cause (measure) to effect (shift in indicator) should be formulated to solve the meaning and attribution problems.

On Einstein's opponents, and other crackpots

Essay Review of "Einsteins Gegner. Die \"offentliche Kontroverse um die Relativit\"atstheorie in den 1920er Jahren" by Milena Wazeck.Comment: 6 page

The reception of relativity in the Netherlands

This article reviews the early academic and public reception of Albert Einstein's theory of relativity in the Netherlands, particularly after Arthur Eddington's eclipse experiments of 1919. Initially, not much attention was given to relativity, as it did not seem an improvement over Hendrik A. Lorentz' work. This changed after the arrival in Leiden of Paul Ehrenfest. Soon relativity was much studied and lead to controversy among a number of conservative intellectuals, as elsewhere in Europe. The tone of Dutch critics was much more mild, however. This can be understood when one considers Dutch neutrality during World War I. Einstein's political positions were generally positively perceived in Holland, which Dutch academics put to use in their efforts at international reconciliation abroad, and the presentation of theoretical physics at home

Orbital-selective Mott transitions in two-band Hubbard models

The anisotropic two-orbital Hubbard model is investigated at low temperatures using high-precision quantum Monte Carlo (QMC) simulations within dynamical mean-field theory (DMFT). We demonstrate that two distinct orbital-selective Mott transitions (OSMTs) occur for a bandwidth ratio of 2 even without spin-flip contributions to the Hund exchange, and we quantify numerical errors in earlier QMC data which had obscured the second transition. The limit of small inter-orbital coupling is introduced via a new generalized Hamiltonian and studied using QMC and Potthoff's self-energy functional method, yielding insight into the nature of the OSMTs and the non-Fermi-liquid OSM phase and opening the possibility for a new quantum-critical point.Comment: 2 pages, 4 figures, presented at ICM2006 and accepted for JMM

Ground State Properties of an Asymmetric Hubbard Model for Unbalanced Ultracold Fermionic Quantum Gases

In order to describe unbalanced ultracold fermionic quantum gases on optical lattices in a harmonic trap, we investigate an attractive ($U<0$) asymmetric ($t_\uparrow\neq t_\downarrow$) Hubbard model with a Zeeman-like magnetic field. In view of the model's spatial inhomogeneity, we focus in this paper on the solution at Hartree-Fock level. The Hartree-Fock Hamiltonian is diagonalized with particular emphasis on superfluid phases. For the special case of spin-independent hopping we analytically determine the number of solutions of the resulting self-consistency equations and the nature of the possible ground states at weak coupling. Numerical results for unbalanced Fermi-mixtures are presented within the local density approximation. In particular, we find a fascinating shell structure, involving normal and superfluid phases. For the general case of spin-dependent hopping we calculate the density of states and the possible superfluid phases in the ground state. In particular, we find a new magnetized superfluid phase.Comment: 9 pages, 5 figure

How Dark Matter Came to Matter

The history of the dark matter problem can be traced back to at least the 1930s, but it was not until the early 1970s that the issue of 'missing matter' was widely recognized as problematic. In the latter period, previously separate issues involving missing mass were brought together in a single anomaly. We argue that reference to a straightforward 'accumulation of evidence' alone is inadequate to comprehend this episode. Rather, the rise of cosmological research, the accompanying renewed interest in the theory of relativity and changes in the manpower division of astronomy in the 1960s are key to understanding how dark matter came to matter. At the same time, this story may also enlighten us on the methodological dimensions of past practices of physics and cosmology.Comment: Accepted for publication in Nature Astronomy. Corrected typ