Peter Davies

The massless Thirring model of a self-interacting ferinion field in a curved two-dimensional background spacetime is considered. The exact operator solution for the fields and the equation for the two-point function are given and used to examine the radiation emitted by a two-dimensional black hole. The radiation is found to be thermal in nature, confirming general predictions to this effect. We compute the particle spectrum of the Thirring fermions at finite temperature in Minkowski space and point out errors in a previous attempt at this calculation. Finally we calculate the vacuum expectation value of the stress tensor in an arbitrary two-dimensional spacetime by exploiting the connection between the thermal Hawking radiation from a black hole and the value of the so-called conformal trace anomaly. The latter is also computed quite independently, using dimensional regularization, from general considerations of the renormalization group.

The generalized second law of thermodynamics states that entropy always increases when all event horizons are attributed with an entropy proportional to their area. We test the generalized second law by investigating the change in entropy when dust, radiation and black holes cross a cosmological event horizon. We generalize for flat, open and closed Friedmann–Robertson–Walker universes by using numerical calculations to determine the cosmological horizon evolution. In most cases, the loss of entropy from within the cosmological horizon is more than balanced by an increase in cosmological event horizon entropy, maintaining the validity of the generalized second law of thermodynamics. However, an intriguing set of open universe models shows an apparent entropy decrease when black holes disappear over the cosmological event horizon. We anticipate that this apparent violation of the generalized second law will disappear when solutions are available for black holes embedded in arbitrary backgrounds.

Using a model quantum clock, I evaluate an expression for the time of a nonrelativistic quantum particle to transit a piecewise geodesic path in a background gravitational field with small spacetime curvature (gravity gradient), in the case that the apparatus is in free fall. This calculation complements and extends an earlier one (Davies 2004) in which the apparatus is fixed to the surface of the Earth. The result confirms that, for particle velocities not too low, the quantum and classical transit times coincide, in conformity with the principle of equivalence. I also calculate the quantum corrections to the transit time when the de Broglie wavelengths are long enough to probe the spacetime curvature. The results are compared with the calculation of Chiao and Speliotopoulos (2003), who propose an experiment to measure the foregoing effects.

Weak measurements offer new insights into the behavior of quantum systems. Combined with post-selection, quantum mechanics predicts a range of new experimentally testable phenomena. In this paper I consider weak measurements performed on time-dependent pre- and post-selected ensembles, with emphasis on the decay of excited states. The results show that the standard exponential decay law is a limiting case of a more general law that depends on both the time of post-selection and the choice of final state. The generalized law is illustrated for two interesting choices of post-selection.

In this sweeping survey, acclaimed science writers Paul Davies and John Gribbin provide a complete overview of advances in the study of physics that have revolutionized modern science. From the weird world of quarks and the theory of relativity to the latest ideas about the birth of the cosmos, the authors find evidence for a massive paradigm shift. Developments in the studies of black holes, cosmic strings, solitons, and chaos theory challenge commonsense concepts of space, time, and matter, and demand a radically altered and more fully unified view of the universe

Paperback reissue of a book first published in 1991. The authors demonstrate how the materialistic and mechanistic world-view that has dominated western culture and science during the last few centuries is being challenged by the findings of modern physics, ranging from relativity to quantum physics. Includes a bibliography and an index. British-born, Davies is a well-known physicist and has written many other books including 'The Mind of God', winner of the 1992 Eureka Science Book Prize. He is currently professor of mathematical physics at the University of Adelaide. Gribbin trained as an astrophysicist and is now a full-time science writer in Britain.

There is currently an unrecognised conflict between the utilitarian nature of the overall NHS and the basic deontology of the doctor-patient interaction. This conflict leads to mistrust and misunderstanding between managers and clinicians. This misunderstanding is bad for both doctors and managers, and also leads to waste of time and resources, and poorer services to patients. The utilitarian thinkers tend to value finite, short term, evidence based technical interventions, delivered according to specifications and contracts. They appear happy to break care up into smaller pieces, which can then be commissioned from multiple providers. The deontological thinkers tend to think about care delivered through a long term continuous relationship, and regard that relationship as therapeutic and salutogenic in itself. To them breaking care up into smaller fragments is a denial of what caring is really about. Very rarely are either or both sides of this debate fully aware of where their powerfully felt and often well argued positions start from. In this paper we offer an appraisal of the strengths and weaknesses of both moral viewpoints as applied in the UK NHS context and we suggest a way in which they can be reconciled, provided neither is pushed too far or too hard against the other. We believe this reconciliation would be good for patients, doctors, managers and improve the service as a whole.

Available from UMI in association with The British Library. ;This thesis is structured as follows: From the M/O literature, chapter I establishes a 'real world' picture, back to which all must relate. Chapters II-IV look at the broad-sweep influences on the way we conceptualise technology, . They describe how we got to think the way we do think, about technology. Chapter V details the methodology. Chapters VI-IX are the main analysis, . Chapter X concludes the findings. ;The massive increase in the power and pervasiveness of technology this century raises ethical dilemmas of a new order, and hence puts responsible professional action firmly at the centre of managing technology. ;This thesis therefore helps establish an ethical discourse about technology; the values usually hidden in the impressive array of numbers are brought into the open. ;This is achieved by examining the language, themes and methodologies of philosophers of technology, as found in 12 years worth of scholarly output of 'The Society for Philosophy and Technology' . The 223 articles are made accessible by developing taxonomies, which are then put in diagramatic form. A hermeneutic methodology is used, and this, together with the sample frame chosen, means that economic dimensions which usually dominate discussions about technology, are in the background. Other aspects of technology become visible. ;Ethics education is a key outcome of the thesis, and three courses developed from the analysis are outlined in chapter X. The aim is to sensitize students to the ethical dimensions of 'doing technology', to develop their critical thinking skills so they can prioritize ethical problems, to enlarge their capacity to 'act professionally' , to encourage them to develop a sense of their own moral authority, and to help them choose a career they can live with