Quantum logic and decohering histories

An introduction is given to an algebraic formulation and generalisation of the consistent histories approach to quantum theory. The main technical tool in this theory is an orthoalgebra of history propositions that serves as a generalised temporal analogue of the lattice of propositions of standard quantum logic. Particular emphasis is placed on those cases in which the history propositions can be represented by projection operators in a Hilbert space, and on the associated concept of a `history group'.Comment: 14 pages LaTeX; Writeup of lecture given at conference ``Theories of fundamental interactions'', Maynooth Eire 24--26 May 1995

Exploring the needs and experiences of family carers affected by harmful behaviour by the older person for whom they care

This thesis reports a qualitative, empirical study that explored the experiences of family carers affected by violent, abusive or harmful behaviour by the older person for whom they cared. Co-designed with a network of carer-advisors, the empirical phases of the study involved: a systematic literature review of qualitative, quantitative and mixed-methods research; in-depth interviews with twelve female carers affected by harmful behaviour; and five focus groups with thirty-eight health and social care practitioners. Orientated within a social constructionist framework, the carer and practitioner accounts were initially analysed using a thematic approach (Braun & Clarke, 2006). The theory of epistemic injustice and the concept of ‘hermeneutic injustice’ (Fricker, 2007) informed a ‘deeper’, theory-informed synthesis of the accounts. This study suggests that surfacing the powerful and distinctive epistemic and ethical practices that can shape intimate relationships opens important, under-explored lines of inquiry and discussion about what constitutes harm, abuse and risk. Such an approach also highlights how the framing of ‘carer harm’ as a private, moral issue reinforces the view that if adults have the cognitive capacity to make decisions, then they are free to do so and, in effect, to tolerate and live with harm. This study critiques this view and explores the unintended implications that such a perspective can engender. It concludes by considering future directions for research, practice and policy with the aim of improving identification and responses to carer harm

A Bayesian Account of Quantum Histories

We investigate whether quantum history theories can be consistent with Bayesian reasoning and whether such an analysis helps clarify the interpretation of such theories. First, we summarise and extend recent work categorising two different approaches to formalising multi-time measurements in quantum theory. The standard approach consists of describing an ordered series of measurements in terms of history propositions with non-additive `probabilities'. The non-standard approach consists of defining multi-time measurements to consist of sets of exclusive and exhaustive history propositions and recovering the single-time exclusivity of results when discussing single-time history propositions. We analyse whether such history propositions can be consistent with Bayes' rule. We show that certain class of histories are given a natural Bayesian interpretation, namely the linearly positive histories originally introduced by Goldstein and Page. Thus we argue that this gives a certain amount of interpretational clarity to the non-standard approach. We also attempt a justification of our analysis using Cox's axioms of probability theory.Comment: 24 pages, accepted for publication in Annals of Physics, minor correctio

The Effect of Social Capital on Fertilizer Adoption: Evidence from Rural Tanzania

Do the characterisitics of local social structures affect fertilizer adoption among rural households? This paper extends the model of technology adoption of Feder and Slade (1984) to incorporate social capital, and then tests the model with household data from two agro-ecological zones in rural Tanzania. Probit estimates of the model show that the probability of adoption of improved fertilizer in 1994-95 in the Central Plateau region in increasing in land under cultivation, cumulative adoption patterns, ethnically-based social affiliations, the adoption of improved seeds, the availability of credit and extension services, and the average years of residence in the village. In the Plains region, this probability is increasing in land under cultivation, ethnically based social affiliations and consultative norms. Overall, these results, which are robust after testing for the likely reverse causality of land under cultivation, support the finding that ethnically based and participatory social affiliations act as forms of social capital in the adoption decision.social capital, technology adoption, Tanzania