Decoherence in Discrete Quantum Walks

We present an introduction to coined quantum walks on regular graphs, which have been developed in the past few years as an alternative to quantum Fourier transforms for underpinning algorithms for quantum computation. We then describe our results on the effects of decoherence on these quantum walks on a line, cycle and hypercube. We find high sensitivity to decoherence, increasing with the number of steps in the walk, as the particle is becoming more delocalised with each step. However, the effect of a small amount of decoherence can be to enhance the properties of the quantum walk that are desirable for the development of quantum algorithms, such as fast mixing times to uniform distributions.Comment: 15 pages, Springer LNP latex style, submitted to Proceedings of DICE 200

A Quarterly Post-World War II Real GDP Series for New Zealand

There are no official quarterly real GDP estimates for New Zealand for the period prior to 1977. We develop a seasonally adjusted series for 1947q2 to 2006q2, by linking quarterly observations from two recent official series to temporally disaggregated observations for an earlier time period. Annual real GDP series are disaggregated, using the information from two quarterly diffusion indexes, developed by Haywood and Campbell (1976). Three econometric models are used: the Chow and Lin (1971) model that disaggregates the level of GDP, and the Fernández (1981) and Litterman (1983) models that disaggregate changes in GDP. Statistical properties of the series are evaluated, and movements in the new series are benchmarked against qualitative research findings from New Zealand's post-WWII economic history. Our preferred quarterly series is based on results generated from the Chow-Lin model.Quarterly real GDP series; temporal disaggregation; business cycles; New Zealand

Wider Horizons: a regional portal for lifelong learning

The paper describes the development of a major new regional online service. Our project is creating an online educational environment open to students and members of the public to provide them with services and information they need to progress from one form of education to another within the local region. The project is being carried out at the University of Worcester in collaboration with the Hereford and Worcester Lifelong Learning Network, one of a series of networks set up across the UK. We hope that the outcome of our project will lead to setting up of similar systems in other regions, and indeed, in other parts of Europe

On-line Repositories for Learning and Teaching: Putting People First.

This short paper outlines the development of a new style of online repository carried out at the University of Worcester in collaboration with the University of Southampton. The work was part funded by JISC and the initial development took place during 2009 - 2010. The new approach is one in which the needs of the user, and the whole orientation of the user interface is user-centred, rather than resource-centred, in the spirit of Web 2.0. The accompanying powerpoint was presented to the EUNIS conference in June 2010 by Viv Bell on behalf of both authors

The expressive power of quantum walks in terms of language acceptance

Discrete time quantum walks are known to be universal for quantum computation. This has been proven by showing that they can simulate a universal quantum gate set. In this paper, we examine computation by quantum walks in terms of language acceptance, and present two ways in which discrete time quantum walks can accept some languages with certainty. These walks can take quantum as well as classical inputs, and we show that when the input is quantum, the walks can also be interpreted as performing the task of quantum state discrimination.Comment: In Proceedings QPL 2012, arXiv:1407.842