Higher dimensional quantum communication in a curved spacetime: an efficient simulation of the propagation of the wavefront of a photon

A photon with a modulated wavefront can produce a quantum communication channel in a larger Hilbert space. For example, higher dimensional quantum key distribution (HD-QKD) can encode information in the transverse linear momentum (LM) or orbital angular momentum (OAM) modes of a photon. This is markedly different than using the intrinsic polarization of a photon. HD-QKD has advantages for free space QKD since it can increase the communication channel\~Os tolerance to bit error rate (BER) while maintaining or increasing the channels bandwidth. We describe an efficient numerical simulation of the propagation photon with an arbitrary complex wavefront in a material with an isotropic but inhomogeneous index of refraction. We simulate the waveform propagation of an optical vortex in a volume holographic element in the paraxial approximation using an operator splitting method. We use this code to analyze an OAM volume-holographic sorter. Furthermore, there are analogue models of the evolution of a wavefront in the curved spacetime environs of the Earth that can be constructed using an optical medium with a given index of refraction. This can lead to a work-bench realization of a satellite HD-QKD system.Comment: 20 pages, 7 figure

Book review: a practical guide for policy analysis: theeightfold path to more effective problem solving

Presenting a concrete plan of action for anyone who needs to perform a policy analysis, Eugene Bardach’s fourth edition is full of helpful tips and case studies written to enthuse and appeal to undergraduate students. Jennifer Miller finds that the book steers clear of technocratic jargon and ideological bias, and believes that it will continue to play an important role in the professional development of policy analysts

X: Poems & Anti-Poems by Shane Rhodes

A review of Shane Rhodes\u27 X: Poems & Anti-Poems. This review focuses on the link between language and landscape, and considers the ways in which that link, reflected in Rhodes\u27 work, comments upon the use of language as an oppressive tool in the treatment of Native Americans and Canadians

Commercialisation of government communications:submission to the Government Communications Review Group, Stirling Media Research Institute

Much of the debate around government communications has focused on the use of special advisers, the lobby system and the centralisation of the system under Alastair Campbell. This is a legitimate focus and much has been said on this topic which is borne out by our own research.2 However the purpose of this submission is to raise a different set of issues which are less often discussed. These relate in particular to the organisation of the civil service and government communications and to the increased role of commercial agencies and commercial criteria in running and evaluating government communications. I wish to concentrate on six aspects. These do not fit very neatly under the headings of the review but are most relevant to the issues of context, politicisation and organisation

Can the shift from needs-led to outcomes-focused assessment in health and social care deliver on policy priorities?

Assessment, planning and review are at the heart of the provision of services and support in health and social care in the community, providing key means through which professionals interact with people using their services. These interactions provide opportunities for relationship building, with evidence that involving the person in identifying their priorities and required support can itself improve outcomes. At the same time, professionals use assessment to assess eligibility for support, and assessment has also increasingly become a mechanism for data gathering, to inform a range of requirements at local and national level including planning, commissioning, inspection and performance management. Despite attempts to move assessment from being service-led to person-centred, meeting such a broad range of objectives and requirements can create tensions at the front line, influencing both how interactions are conducted, and the resulting decisions. More recently, there has been an increasing emphasis on outcomes for individuals using health and social care services, including a shift from needs-led to outcomes-focused assessment. This paper considers a recent literature review about shared health and social care assessment, including emerging evidence from the implementation of outcomes-focused assessment in the UK. It concludes that there are promising signs that the recent shift to outcomes-focused assessment might resolve longstanding tensions around assessment, delivering on person-centred objectives and resulting in more efficient and effective use of resources

How to Determine Shrinkage in Grain

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