Multi-ion sensing of dipolar noise sources in ion traps

Trapped-ion quantum platforms are subject to `anomalous' heating due to interactions with electric-field noise sources of nature not yet completely known. There is ample experimental evidence that this noise originates at the surfaces of the trap electrodes, and models assuming fluctuating point-like dipoles are consistent with observations, but the exact microscopic mechanisms behind anomalous heating remain undetermined. Here we show how a two-ion probe displays a transition in its dissipation properties, enabling experimental access to the mean orientation of the dipoles and the spatial extent of dipole-dipole correlations. This information can be used to test the validity of candidate microscopic models, which predict correlation lengths spanning several orders of mag- nitude. Furthermore, we propose an experiment to measure these effects with currently-available traps and techniques

Regional wage convergence in Spain : 1850-1930

Real wages PPP adjusted are used to analyse labour market integration in Spain. In contrast to earlier research analysing migration and nominal wages rates, our research seems to indicate that a well-integrated labour market had emerged in Spain by 1914 and substantial wage convergence happened from 1850 to 1914 with low rates of interna l migration. The shock of World War I and the subsequent globalisation backlash appear to disrupt this integrated market provoking a spectacular increase in wage differentials across regions and provinces. However, real wage convergence across Spanish provinces resumed powerfully over 1920s, this time accompanied by high internal migrations

Regional wage convergence in Spain : 1850-1930.

Real wages PPP adjusted are used to analyse labour market integration in Spain. In contrast to earlier research analysing migration and nominal wages rates, our research seems to indicate that a well-integrated labour market had emerged in Spain by 1914 and substantial wage convergence happened from 1850 to 1914 with low rates of interna l migration. The shock of World War I and the subsequent globalisation backlash appear to disrupt this integrated market provoking a spectacular increase in wage differentials across regions and provinces. However, real wage convergence across Spanish provinces resumed powerfully over 1920s, this time accompanied by high internal migrations.

Regional wage convergence in Spain : 1850-1930.

This paper presents a new regional database on real wages for Spain from 1850 to 1930. This evidence is used to analyze the evolution of wages across regions and occupations. Sub stantial wage convergence occurred from 1850 to 1914, despite low rates of internal migration. World War I and the subsequent globalization backlash were associated with a spectacular in crease in wage differentials. However, real wage convergence across Spanish provinces re sumed during the 1920s, this time accompanied by high rates of internal migrationWage convergence; Labor markets; Migration; Growth regressions;

Geometric phases in 2D and 3D polarized fields: geometrical, dynamical, and topological aspects

Geometric phases are a universal concept that underpins numerous phenomena involving multi-component wave fields. These polarization-dependent phases are inherent in interference effects, spin-orbit interaction phenomena, and topological properties of vector wave fields. Geometric phases have been thoroughly studied in two-component fields, such as two-level quantum systems or paraxial optical waves. However, their description for fields with three or more components, such as generic nonparaxial optical fields routinely used in modern nano-optics, constitutes a nontrivial problem. Here we describe geometric, dynamical, and total phases calculated along a closed spatial contour in a multi-component complex field, with particular emphasis on 2D (paraxial) and 3D (nonparaxial) optical fields. We present several equivalent approaches: (i) an algebraic formalism, universal for any multi-component field; (ii) a dynamical approach using the Coriolis coupling between the spin angular momentum and reference-frame rotations; and (iii) a geometric representation, which unifies the Pancharatnam-Berry phase for the 2D polarization on the Poincar\'e sphere and the Majorana-sphere representation for the 3D polarized fields. Most importantly, we reveal close connections between geometric phases, angular-momentum properties of the field, and topological properties of polarization singularities in 2D and 3D fields, such as C-points and polarization M\"obius strips.Comment: 21 pages, 11 figures, to appear in Rep. Prog. Phy

Assessing the long-distance repellency of long-lasting insecticide netting to a suite of post-harvest insects

Insects are our main competitors for food on the planet (1). In fact, growers lose 10-30% of crops during storage, processing, and marketing after harvest each year to stored product insects (2,3). Challenges to current management include increasing insecticide resistance to phosphine (4), which is the most common insect fumigant. Another challenge has been an increasing demand for organic or low insecticide-input products by consumers (5). To meet these challenges we came up with an alternative management approach, a long lasting insecticide netting (LLIN). Insecticide-treated nets have been widely used as a tool for malaria vector control in tropical regions since the early 1990s (6). These nets are typically treated with a pyrethroid insecticide, such as permethrin or deltamethrin, which repel, incapacitate, and kill mosquitoes that land on the nets. Researchers have recently begun exploring the use of LLINs for management of agricultural pests in high value specialty crops (7). More recently, work with LLINs in post-harvest settings has demonstrated that this tool can induce mortality, as well as significantly decrease the movement and dispersal capacity of post-harvest insects (8). Some possible uses for LLIN include being used to line windows, vents, eaves, or other openings into food facilities. However, anecdotal evidence from IPM practitioners has suggested that pyrethroids, which the LLIN contains, may be repellent to specific groups of insects. In order for LLIN to be an effective tool at intercepting and preventing infestation by stored product insects, we must demonstrate that the netting is not repellent to a range of post-harvest insects