RF-dressed Rydberg atoms in hollow-core fibres

The giant electro-optical response of Rydberg atoms manifests itself in the emergence of sidebands in the Rydberg excitation spectrum if the atom is exposed to a radio-frequency (RF) electric field. Here we report on the study of RF-dressed Rydberg atoms inside hollow-core photonic crystal fibres (HC-PCF), a system that enables the use of low modulation voltages and offers the prospect of miniaturised vapour-based electro-optical devices. Narrow spectroscopic features caused by the RF field are observed for modulation frequencies up to 500 MHz.This is the author accepted manuscript. It is currently under an indefinite embargo pending publication by the Institute of Physics

Economics of education research: a review and future prospects

In this paper we offer an appraisal of the economics of education research area, charting its history as a field and discussing the ways in which economists have contributed both to education research and to education policy-making. In particular, we highlight the theoretical and methodological contributions that economists have made to the field of education during the last 50 years. Despite the success of the economics of education as a field of inquiry, we argue that some of the contributions made by economists could be limited if the economics of education is seen as quite distinct from the other disciplines working in the field of education. In these areas of common interest, economists need to work side by side with the other major disciplines in the field of education if their contribution to the field is to be maximised, particularly in terms of applying improved methodology. We conclude that the study of education acquisition and its economic and social impact in the economics of education research area is very likely to remain a fertile research ground. Acknowledgement

Truncating first-order Dyson-Schwinger equations in Coulomb-Gauge Yang-Mills theory

The non-perturbative domain of QCD contains confinement, chiral symmetry breaking, and the bound state spectrum. For the calculation of the latter, the Coulomb gauge is particularly well-suited. Access to these non-perturbative properties should be possible by means of the Green's functions. However, Coulomb gauge is also very involved, and thus hard to tackle. We introduce a novel BRST-type operator r, and show that the left-hand side of Gauss' law is r-exact. We investigate a possible truncation scheme of the Dyson-Schwinger equations in first-order formalism for the propagators based on an instantaneous approximation. We demonstrate that this is insufficient to obtain solutions with the expected property of a linear-rising Coulomb potential. We also show systematically that a class of possible vertex dressings does not change this result.Comment: 22 pages, 4 figures, 1 tabl

Rydberg atoms in hollow-core photonic crystal fibres.

The exceptionally large polarizability of highly excited Rydberg atoms-six orders of magnitude higher than ground-state atoms--makes them of great interest in fields such as quantum optics, quantum computing, quantum simulation and metrology. However, if they are to be used routinely in applications, a major requirement is their integration into technically feasible, miniaturized devices. Here we show that a Rydberg medium based on room temperature caesium vapour can be confined in broadband-guiding kagome-style hollow-core photonic crystal fibres. Three-photon spectroscopy performed on a caesium-filled fibre detects Rydberg states up to a principal quantum number of n=40. Besides small energy-level shifts we observe narrow lines confirming the coherence of the Rydberg excitation. Using different Rydberg states and core diameters we study the influence of confinement within the fibre core after different exposure times. Understanding these effects is essential for the successful future development of novel applications based on integrated room temperature Rydberg systems

Induced Gravity on Intersecting Branes

We establish Einstein-Hilbert gravity couplings in the effective action for Intersecting Brane Worlds. The four-dimensional induced Planck mass is determined by calculating graviton scattering amplitudes at one-loop in the string perturbation expansion. We derive a general formula linking the induced Planck mass for N=1 supersymmetric backgrounds directly to the string partition function. We carry out the computation explicitly for simple examples, obtaining analytic expressions.Comment: references added, minor changes to discussion of path integral normalization on page

Dataset of coded handwriting features for use in statistical modelling

© 2017 The Authors The data presented here is related to the article titled, “Using handwriting to infer a writer's country of origin for forensic intelligence purposes” (Agius et al., 2017) [1]. This article reports original writer, spatial and construction characteristic data for thirty-seven English Australian1 writers and thirty-seven Vietnamese writers. All of these characteristics were coded and recorded in Microsoft Excel 2013 (version 15.31). The construction characteristics coded were only extracted from seven characters, which were: ‘g’ ‘h’ ‘th’ ‘M’ ‘0’ ‘7’ and ‘9’. The coded format of the writer, spatial and construction characteristics is made available in this Data in Brief in order to allow others to perform statistical analyses and modelling to investigate whether there is a relationship between the handwriting features and the nationality of the writer, and whether the two nationalities can be differentiated. Furthermore, to employ mathematical techniques that are capable of characterising the extracted features from each participant

Heat-kernel expansion and counterterms of the Faddeev-Popov determinant in Coulomb and Landau gauge

The Faddeev-Popov determinant of Landau gauge in d dimensions and Coulomb gauge in d+1 dimensions is calculated in the heat-kernel expansion up to next-to-leading order. The UV-divergent parts in d=3,4 are isolated and the counterterms required for a non-perturbative treatment of the Faddeev-Popov determinant are determined.Comment: 7 page

The ghost-gluon vertex in Hamiltonian Yang-Mills theory in Coulomb gauge

The Dyson-Schwinger equation for the ghost-gluon vertex of the Hamiltonian approach to Yang-Mills theory in Coulomb gauge is solved at one-loop level using as input the non-perturbative ghost and gluon propagators previously determined within the variational approach. The obtained ghost-gluon vertex is IR finite but IR enhanced compared to the bare one by 15% to 25%, depending on the kinematical momentum regime.Comment: 7 pages, 5 eps figure