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  1. P. C. W. Davies, Acceleration Radiation in a Compact Space.
    We study the response of a uniformly accelerated model particle detector in a spacetime with compact spatial sections. The basic thermal character of the response re-emerges, in spite of the fact that the spacetime does not possess event horizons. Our model also permits a study of detector response to twisted field states.
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  2. P. C. W. Davies, Cosmological Horizons and Entropy.
    An analogue of Hawking's black hole area theorem is proved for Friedmann-type cosmological models with event horizons. The generalised second law of thermodynamics is investigated in cases where the horizon shrinks.
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  3. P. C. W. Davies, Constraints on the Value of the Fine Structure Constant From Gravitational Thermodynamics.
    The fine structure constant α ≡ e2/ c ≈ 1/137 is one of the fundamental parameters of the standard model of particle physics. There is a long history of attempts to derive the measured value of α from an underlying theory, or exhibit it in the form of a compact mathematical expression [2–4, 6, 8, 14–16]. The most significant advance in this endeavour was made by Dirac, who showed that if magnetic monopoles exist, with magnetic charge μ, then..
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  4. P. C. W. Davies, Does Life's Rapid Appearance Imply a Martian Origin?
    The hypothesis that life’s rapid appearance on Earth justifies the belief that life is widespread in the universe has been investigated mathematically by Lineweaver and Davis (Astrobiol- ogy 2002;2:293–304). However, a rapid appearance could also be interpreted as evidence for a nonterrestrial origin. I attempt to quantify the relative probabilities for a non-indigenous ver- sus indigenous origin, on the assumption that biogenesis involves one or more highly im- probable steps, using a generalization of Carter’s well-known observer-selection argument. The analysis is (...)
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  5. P. C. W. Davies, Does Quantum Mechanics Play a Non-Trivial Role in Life?
    There have been many claims that quantum mechanics plays a key role in the origin and/or operation of biological organisms, beyond merely providing the basis for the shapes and sizes of biological molecules and their chemical affinities. These range from Schr¨odinger’s suggestion that quantum fluctuations produce mutations, to Hameroff and Penrose’s conjecture that quantum coherence in microtubules is linked to consciousness. I review some of these claims in this paper, and discuss the serious problem of decoherence. I advance some further (...)
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  6. P. C. W. Davies, Extension of Wheeler-Feynman Quantum Theory to the Relativistic Domain I. Scattering Processes.
    Institute of Theoretical Astronomy, University of Cambridge, Cambridge, UK 3fS. received 28th August 1970, in final revised form 1st July 1971..
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  7. P. C. W. Davies, Multiverse Cosmological Models.
    Recent advances in string theory and inflationary cosmology have led to a surge of interest in the possible existence of an ensemble of cosmic regions, or “universes”, among the members of which key physical parameters, such as the masses of elementary particles and the coupling constants, might assume different values. The observed values in our cosmic region are then attributed to an observer selection effect (the so-called anthropic principle). The assemblage of universes has been dubbed “the multiverse”. In this paper (...)
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  8. P. C. W. Davies, Measurement of the Velocity of a Dirac Particle.
    Using a model quantum clock, I show how the velocity of a relativistic particle can be measured. The results are used to analyse the long-standing problem of the velocity..
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  9. P. C. W. Davies, Massless Thirring Model in Curved Space: Thermal States and Conformal Anomaly.
    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 (...)
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  10. P. C. W. Davies, Mining the Universe.
    The Unruh-Wald scenario for mining quantum black holes is applied to de Sitter space. The following questions are addressed: Will the generalized second law of thermodynamics be maintained for de Sitter horizons? Does the mining process allow the recovery of unlimited energy from the cosmological gravitational field? The evaporation of a black hole in de Sitter space is also investigated in the context of the second law.
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  11. P. C. W. Davies, On Recent Experiments to Detect Advanced Radiation.
    Inconsistencies in the usual interpretation of the absorber theory of radiation are exposed which invalidate an experiment proposed recently by Heron and Pegg. An earlier experiment by Partridge necessarily gave a null result owing to absorption on the far side of the Earth of any advanced radiation which may have been present.
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  12. P. C. W. Davies, Quantum Theory and the Equivalence Principle.
    It is widely accepted that EinstcinRi7;s general theory of relativity is an satisfactory description of gravity 0nly in the macroscopic limit, where quantum eiTcc1;s may be neglected. Presumably this theory is inapplicable at the Planck length (10*33 cm) , but recently much attention has been devoted to gravitational theory at intermediate length scales (10*13 cm) where quantum affects 0f matter are inescapable, but where there is an general assumption that the gravitational Held may bc treated as a classical background, (...)
     
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  13. P. C. W. Davies, Quantum Vacuum Instability Near Rotating Stars.
    We discuss the Starobinskii-Unruh process for the Kerr black hole. We show how this effect is related to the theory of squeezed states. We then consider a simple model for a highly relativistic rotating star and show that the Starobinskii-Unruh effect is absent.
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  14. P. C. W. Davies, Transit Time of a Freely Falling Quantum Particle in a Background Gravitational Field.
    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 (...)
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  15. P. C. W. Davies, Time Variation of the Coupling Constants.
    of a logarithmic time dependence of the fine structure constant is apparently within the limits discussed if there is a corresponding logarithmic time dependence of the strong coupling constant also. Moreover the recent discover> of naturally occurring ' Pu places the Gamow hypothesis of e' r much nearer the allov'able limits than had previously been supposed.
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  16. P. C. W. Davies & S. A. Fulling, Energy-Momentum Tensor Near an Evaporating Black Hole.
    two dimensions, quantum radiation production is incompatible with a conserved and traceless T„,. We therefore resolve an ambiguity in our expression for Tr„, regularized by a geodesic point-separation procedure.
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  17. Tamara M. Davis & P. C. W. Davies, Black Hole Versus Cosmological Horizon Entropy.
    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 (...)
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  18. P. C. W. Davies, Time-Dependent Quantum Weak Values: Decay Law for Post-Selected States.
    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 (...)
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  19. P. C. W. Davies & Niels Henrik Gregersen (eds.) (2010). Information and the Nature of Reality: From Physics to Metaphysics. Cambridge University Press.
    Machine generated contents note: 1. Introduction: does information matter?; Paul Davies and Niels Henrik Gregersen; Part I. History: 2. From matter to materialism ... and (almost) back Ernan McMullin; 3. Unsolved dilemmas: the concept of matter in the history of philosophy and in contemporary physics Philip Clayton; Part II. Physics: 4. Universe from bit Paul Davies; 5. The computational universe Seth Lloyd; 6. Minds and values in the quantum universe Henry Pierce Stapp; Part III. Biology: 7. The concept of information (...)
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  20. P. C. W. Davies (2007). The Matter Myth: Dramatic Discoveries That Challenge Our Understanding of Physical Reality. Simon & Schuster.
    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 (...)
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  21. Philip Clayton & P. C. W. Davies (eds.) (2006). The Re-Emergence of Emergence: The Emergentist Hypothesis From Science to Religion. Oxford University Press.
    This volume introduces readers to emergence theory, outlines the major arguments in its defence, and summarizes the most powerful objections against it. It provides the clearest explication yet of this exciting new theory of science, which challenges the reductionist approach by proposing the continuous emergence of novel phenomena.
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  22. P. C. W. Davies (2004). Emergent Biological Principles and the Computational Properties of the Universe: Explaining It or Explaining It Away. Complexity 10 (2):11-15.
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  23. P. C. W. Davies (1998). Our Place in the Universe. In John Leslie (ed.), Modern Cosmology & Philosophy. Prometheus Books. 311--318.
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  24. P. C. W. Davies (1996). The Big Questions. Penguin Books.
  25. P. C. W. Davies & Jill Gready (eds.) (1995). God, Cosmos, Nature, and Creativity. Scottish Academic Press.
     
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  26. P. C. W. Davies (1994). [Book Review] the Mind of God, the Scientific Basis for a Rational World. [REVIEW] Science and Society 58 (2):233-237.
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  27. P. C. W. Davies (1990). Other Worlds. Penguin Books.
  28. P. C. W. Davies (1972). 1. Cosmic Time. In J. T. Fraser, F. Haber & G. Muller (eds.), The Study of Time. Springer-Verlag. 3--74.
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