Optimal experiment design revisited: fair, precise and minimal tomography

Given an experimental set-up and a fixed number of measurements, how should one take data in order to optimally reconstruct the state of a quantum system? The problem of optimal experiment design (OED) for quantum state tomography was first broached by Kosut et al. [arXiv:quant-ph/0411093v1]. Here we provide efficient numerical algorithms for finding the optimal design, and analytic results for the case of 'minimal tomography'. We also introduce the average OED, which is independent of the state to be reconstructed, and the optimal design for tomography (ODT), which minimizes tomographic bias. We find that these two designs are generally similar. Monte-Carlo simulations confirm the utility of our results for qubits. Finally, we adapt our approach to deal with constrained techniques such as maximum likelihood estimation. We find that these are less amenable to optimization than cruder reconstruction methods, such as linear inversion.Comment: 16 pages, 7 figure

A physics-based life prediction methodology for thermal barrier coating systems

A novel mechanistic approach is proposed for the prediction of the life of thermal barrier coating (TBC) systems. The life prediction methodology is based on a criterion linked directly to the dominant failure mechanism. It relies on a statistical treatment of the TBC's morphological characteristics, non-destructive stress measurements and on a continuum mechanics framework to quantify the stresses that promote the nucleation and growth of microcracks within the TBC. The last of these accounts for the effects of TBC constituents' elasto-visco-plastic properties, the stiffening of the ceramic due to sintering and the oxidation at the interface between the thermally insulating yttria stabilized zirconia (YSZ) layer and the metallic bond coat. The mechanistic approach is used to investigate the effects on TBC life of the properties and morphology of the top YSZ coating, metallic low-pressure plasma sprayed bond coat and the thermally grown oxide. Its calibration is based on TBC damage inferred from non-destructive fluorescence measurements using piezo-spectroscopy and on the numerically predicted local TBC stresses responsible for the initiation of such damage. The potential applicability of the methodology to other types of TBC coatings and thermal loading conditions is also discussed

The contested and contingent outcomes of Thatcherism in the UK

The death of Margaret Thatcher in April 2013 sparked a range of discussions and debates about the significance of her period in office and the political project to which she gave her name: Thatcherism. This article argues that Thatcherism is best understood as a symbolically important part of the emergence of first-phase neoliberalism. It engages with contemporary debates about Thatcherism among Marxist commentators and suggests that several apparently divergent positions can help us now reach a more useful analysis of Thatcherism’s short- and long-term outcomes for British political economy. The outcomes identified include: an initial crisis in the neoliberal project in the UK; the transformation of the party political system to be reflective of the politics of neoliberalism, rather than its contestation; long-term attempts at the inculcation of the neoliberal individual; de-industrialisation and financial sector dependence; and a fractured and partially unconscious working class. In all long-term outcomes, the contribution of Thatcherism is best understood as partial and largely negative, in that it cleared the way for a longer-term and more constructive attempt to embed neoliberal political economy. The paper concludes by suggesting that this analysis can inform current debates on the left of British politics about how to oppose and challenge the imposition of neoliberal discipline today

Phase 2 of the Multiple Provider Employment Zones Qualitative Study, DWP Research Report 399

This report presents the findings of a qualitative study of the operation and impact of the Multiple Provider Employment Zone (MPEZ) initiatives that have operated in four cities (London, Birmingham, Liverpool and Glasgow) since 20041. The study builds on earlier work by Cambridge Policy Consultants (Hirst et al. 2006), which concentrated on issues related to the early establishment of the MPEZ initiative and the initial experiences of Providers, Jobcentre Plus districts and customers. The Phase 2 research took place approximately one year on from the Phase 1 study and focused on tracking developments in the operation of MPEZ as the initiative became more established. The study involved interviews with EZ Providers (managers and Advisers), Jobcentre Plus representatives (managers and Advisers) and customers (young people (aged 18-24) claiming Jobseeker’s Allowance (JSA), who would otherwise have returned to New Deal for Young People (NDYP)2, lone parents receiving Income Support and early entrants – see section 1.6 for full details). In order to gain a wider perspective, researchers also spoke to representatives of organisations that have employed MPEZ participants and a number of stakeholder organisations with a broad interest in local labour market policies and programmes in the MPEZ areas. In total, the research involved interviews or group discussions with over 300 individuals, providing a range and depth of qualitative information that allows a detailed picture to be established of the way that MPEZs developed between mid- 2005 and mid-2006, including the experiences of employers and the labour market destinations of MPEZ participants. A central issue addressed in the research and in this report is the ‘multiple’ element of the initiative and the value that is added through the existence of more than one Provider in each MPEZ area. Questions of allocation, choice, specialisation, competition and innovation are considered from the perspectives of Providers, Jobcentre Plus, customers, employers and stakeholders and the final sections present some conclusions and issues for consideration in relation to these topics

Social gradients in the receipt of medication for attention-deficit hyperactivity disorder in children and young people in Sheffield

Background Attention deficit hyperactivity disorder (ADHD) is a common neurodevelopmental disorder characterised by inattention and hyperactivity-impulsivity that can affect people throughout their lifecourse. A social gradient exists in the prevalence of ADHD in the UK. Studies in other countries have shown that social gradients also exist in the receipt of medication for ADHD. Socioeconomic position is potentially an unrecognised and modifiable factor in children and young people’s receipt of medication for ADHD in the UK. Aim The aim of the study was to investigate if socioeconomic could explain in part whether or not children and young people in Sheffield are receiving medication for ADHD. Method We used multivariable logistic regression modelling to investigate whether socioeconomic could explain variation in receipt of medication for ADHD in children and young people in a cross sectional study. We collected data from 1354 children and young people with a diagnosis of ADHD across three Sheffield centres between January and December 2016. Independent variables were age, sex, religion, ethnicity, comorbidities, and Index of Multiple Deprivation decile (derived from home postcode). Results Our results showed a social gradient in the receipt of medication for ADHD (p<0.01); an increase in one decile of the Index of Multiple Deprivation was associated with 10% lower odds of receipt of medication for ADHD (aOR 0.90; 95%CI 0.84–0.970). Conclusion Children and young people from more deprived backgrounds are more likely to receive medication for ADHD. This is the first time that a social gradient in children and young people’s receipt of medication for ADHD has been shown in a UK sample

High-speed noise-free optical quantum memory

Quantum networks promise to revolutionise computing, simulation, and communication. Light is the ideal information carrier for quantum networks, as its properties are not degraded by noise in ambient conditions, and it can support large bandwidths enabling fast operations and a large information capacity. Quantum memories, devices that store, manipulate, and release on demand quantum light, have been identified as critical components of photonic quantum networks, because they facilitate scalability. However, any noise introduced by the memory can render the device classical by destroying the quantum character of the light. Here we introduce an intrinsically noise-free memory protocol based on two-photon off-resonant cascaded absorption (ORCA). We consequently demonstrate for the first time successful storage of GHz-bandwidth heralded single photons in a warm atomic vapour with no added noise; confirmed by the unaltered photon statistics upon recall. Our ORCA memory platform meets the stringent noise-requirements for quantum memories whilst offering technical simplicity and high-speed operation, and therefore is immediately applicable to low-latency quantum networks

Manipulation of drugs to achieve the required dose is intrinsic to paediatric practice but is not supported by guidelines or evidence

Background: A lack of age-appropriate formulations can make it difficult to administer medicines to children. A manipulation of the dosage form may be required to achieve the required dose. This study aimed to describe medicines that are manipulated to achieve the required dose in paediatric practice.Method: A structured, undisguised observational study and postal survey. The observational study investigated drug manipulations occurring in clinical practice across three sites. The questionnaire, administered to a sample of paediatric nurses throughout the UK, surveyed manipulations conducted and nurses' experiences and views.Results: The observational study identified 310 manipulations, of which 62% involved tablets, 21% were intravenous drugs and 10% were sachets. Of the 54 observed manipulations 40 involved tablets with 65% of the tablets being cut and 30% dispersed to obtain a smaller dose. 188 manipulations were reported by questionnaire respondents, of these 46% involved tablets, 12% were intravenous drugs, and 12% were nebuliser solutions. Manipulations were predominantly, but not exclusively, identified in specialist clinical areas with more highly dependent patients. Questionnaire respondents were concerned about the accuracy of the dose achieved following manipulations and the lack of practice guidance.Conclusion: Manipulations to achieve the required dose occur throughout paediatric in-patient settings. The impact of manipulations on the efficacy of the drugs, the accuracy of the dose and any adverse effects on patients is not known. There is a need to develop evidence-based guidance for manipulations of medicines in children

Interfacing GHz-bandwidth heralded single photons with a room-temperature Raman quantum memory

Photonics is a promising platform for quantum technologies. However, photon sources and two-photon gates currently only operate probabilistically. Large-scale photonic processing will therefore be impossible without a multiplexing strategy to actively select successful events. High time-bandwidth-product quantum memories - devices that store and retrieve single photons on-demand - provide an efficient remedy via active synchronisation. Here we interface a GHz-bandwidth heralded single-photon source and a room-temperature Raman memory with a time-bandwidth product exceeding 1000. We store heralded single photons and observe a clear influence of the input photon statistics on the retrieved light, which agrees with our theoretical model. The preservation of the stored field's statistics is limited by four-wave-mixing noise, which we identify as the key remaining challenge in the development of practical memories for scalable photonic information processing

The political economy of Public Employment Services: measurement and disempowered empowerment?

Active Labour Market Policies (ALMPs) and Public Employment Services (PES) are related components of the European Union and member state labour market policy. Typically, PES are analysed in terms of a narrow concern with efficiency and effectiveness of service. In this paper, we argue that PES are constituents in broader processes. They are not just means to facilitate employment, they are also part of transmission mechanisms for a political economy of competitiveness. They play a particular role in governance processes, and so serve to produce and reproduce power relations that are intrinsic to those processes. We argue that the technical ways that PES have been managed over recent decades has contributed to broader processes of disempowering labour, through depoliticized management practices. We argue that attempts at even limited re-empowerment of labour would require a repoliticization of these management practices