Nonclassical statistics of intracavity coupled χ(2)\chi^{(2)} waveguides: the quantum optical dimer

A model is proposed where two $\chi^{(2)}$ nonlinear waveguides are contained in a cavity suited for second-harmonic generation. The evanescent wave coupling between the waveguides is considered as weak, and the interplay between this coupling and the nonlinear interaction within the waveguides gives rise to quantum violations of the classical limit. These violations are particularly strong when two instabilities are competing, where twin-beam behavior is found as almost complete noise suppression in the difference of the fundamental intensities. Moreover, close to bistable transitions perfect twin-beam correlations are seen in the sum of the fundamental intensities, and also the self-pulsing instability as well as the transition from symmetric to asymmetric states display nonclassical twin-beam correlations of both fundamental and second-harmonic intensities. The results are based on the full quantum Langevin equations derived from the Hamiltonian and including cavity damping effects. The intensity correlations of the output fields are calculated semi-analytically using a linearized version of the Langevin equations derived through the positive-P representation. Confirmation of the analytical results are obtained by numerical simulations of the nonlinear Langevin equations derived using the truncated Wigner representation.Comment: 15 pages, 8 figures, submitted to Phys. Rev.

Quantum properties of transverse pattern formation in second-harmonic generation

We investigate the spatial quantum noise properties of the one dimensional transverse pattern formation instability in intra-cavity second-harmonic generation. The Q representation of a quasi-probability distribution is implemented in terms of nonlinear stochastic Langevin equations. We study these equations through extensive numerical simulations and analytically in the linearized limit. Our study, made below and above the threshold of pattern formation, is guided by a microscopic scheme of photon interaction underlying pattern formation in second-harmonic generation. Close to the threshold for pattern formation, beams with opposite direction of the off-axis critical wave numbers are shown to be highly correlated. This is observed for the fundamental field, for the second harmonic field and also for the cross-correlation between the two fields. Nonlinear correlations involving the homogeneous transverse wave number, which are not identified in a linearized analysis, are also described. The intensity differences between opposite points of the far fields are shown to exhibit sub-Poissonian statistics, revealing the quantum nature of the correlations. We observe twin beam correlations in both the fundamental and second-harmonic fields, and also nonclassical correlations between them.Comment: 18 pages, 17 figures, submitted to Phys. Rev.

Systems of education governance and cultures of justice in Ireland, Scotland and Pakistan

This chapter compares the issue of cultures of justice in the systems of education governance in three education systems: Ireland, Scotland and Pakistan. The focus for the comparison are the current policies which shape the regulation of education. These policies were reviewed to identify key issues relating to social justice and equality, decision-making and accountability. From the analysis of each system, three central issues were identified: firstly, the improvement of a state education system; secondly, the degree of decentralisation and centralisation in governance structures and thirdly, the expectations placed on school leaders. The chapter concludes by discussing the tensions between the drive for system improvement and opportunities for school leaders to build strategies to address issues of inequality in schools

Leucine-rich repeat kinase LRRK1 regulates endosomal trafficking of the EGF receptor

Activation of the epidermal growth factor receptor (EGFR) not only initiates multiple signal-transduction pathways, including the MAP kinase (MAPK) pathway, but also triggers trafficking events that relocalize receptors from the cell surface to intracellular endocytic compartments. In this paper, we demonstrate that leucine-rich repeat kinase LRRK1, which contains a MAPKKK-like kinase domain, forms a complex with activated EGFR through an interaction with Grb2. Subsequently, LRRK1 and epidermal growth factor (EGF) are internalized and co-localized in early endosomes. LRRK1 regulates EGFR transport from early to late endosomes and regulates the motility of EGF-containing early endosomes in a manner dependent on its kinase activity. Furthermore, LRRK1 serves as a scaffold facilitating the interaction of EGFR with the endosomal sorting complex required for transport-0 complex, thus enabling efficient sorting of EGFR to the inner vesicles of multivesicular bodies. Our findings provide the first evidence that a MAPKKK-like protein regulates the endosomal trafficking of EGFR

The fusion approach – applications for understanding local government and European integration

The article explores the theoretical capabilities of the fusion approach as a conceptual ‘kit’ to explain the ‘bigger picture’ of European integration from a local government perspective. Fusion addresses the rationales and methods facilitating the transfer of policy-making competences to the European level. It understands European integration as a merging of public resources and policy instruments from multiple levels of government, whereby accountability and responsibilities for policy outcomes become blurred. The article argues that the fusion approach is useful to explain the systemic linkages between macro-trajectories and the corresponding change at the local level; the fusion dynamics of the local and European levels in a common policy-cycle; and the attitudes of local actors towards the EU. Although the article concludes that local government is rather modestly ‘fused’ into the EU, fusion approaches allow examining the extent to which the local level has become integrated into the European governance system

Telling stories about European Union Health Law: The emergence of a new field of law

The ideational narrative power of law has now solidified, and continues to solidify, ‘European Union health law’, into an entity with a distinctive legal identity. EU health law was previously seen as either non-existent, or so broad as to be meaningless, or as existing only in relations between EU law and health (the ‘and’ approach), or as consisting of a body of barely or loosely connected policy domains (the ‘patchwork’ approach). The process of bringing EU health law into being is a process of narration. The ways in which EU health law is narrated (and continues to be narrated) involve three main groups of actors: the legislature, courts and the academy