12,909 research outputs found

    The Physics of Timelessness

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    The nature of time is yet to be fully grasped and finally agreed upon among physicists, philosophers, psychologists and scholars from various disciplines. Present paper takes clue from the known assumptions of time as - movement, change, becoming - and the nature of time will be thoroughly discussed. The real and unreal existences of time will be pointed out and presented. The complex number notation of nature of time will be put forward. Natural scientific systems and various cosmic processes will be identified as constructing physical form of time and the physical existence of time will be designed. The finite and infinite forms of physical time and classical, quantum and cosmic times will be delineated and their mathematical constructions and loci will be narrated. Thus the physics behind time-construction, time creation and time-measurement will be given. Based on these developments the physics of Timelessness will be developed and presented

    Switching quantum reference frames in the N-body problem and the absence of global relational perspectives

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    Given the importance of quantum reference systems to both quantum and gravitational physics, it is pertinent to develop a systematic method for switching between the descriptions of physics relative to different choices of quantum reference systems, which is valid in both fields. Here, we continue with such a unifying approach, begun in arxiv:1809.00556, whose key ingredients is a gravity-inspired symmetry principle, which enforces physics to be relational and leads, thanks to gauge related redundancies, to a perspective-neutral structure which contains all frame choices at once and via which frame perspectives can be consistently switched. Formulated in the language of constrained systems, the perspective-neutral structure turns out to be the constraint surface classically and the gauge invariant Hilbert space in the Dirac quantized theory. By contrast, a perspective relative to a specific frame corresponds to a gauge choice and the associated reduced phase and Hilbert space. Quantum reference frame switches thereby amount to a symmetry transformation. In the quantum theory, they require a transformation that takes one from the Dirac to a reduced quantum theory and we show that it amounts to a trivialization of the constraints and a subsequent projection onto the classical gauge fixing conditions. We illustrate this method in the relational NN-body problem with rotational and translational symmetry. This model is particularly interesting because it features the Gribov problem so that globally valid gauge fixing conditions are impossible which, in turn, implies also that globally valid relational frame perspectives are absent in both the classical and quantum theory. These challenges notwithstanding, we exhibit how one can systematically construct the quantum reference frame transformations for the three-body problem.Comment: 22 pages, plus appendice

    Inverse relationship between genetic diversity and epigenetic complexity

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    Early studies of molecular evolution revealed a correlation between genetic distance and time of species divergence. This observation provoked the molecular clock hypothesis and in turn the ‘Neutral Theory’, which however remains an incomplete explanation since it predicts a constant mutation rate per generation whereas empirical evidence suggests a constant rate per year. Data inconsistent with the molecular clock hypothesis have steadily accumulated in recent years that show no correlation between genetic distance and time of divergence. It has therefore become a challenge to find a testable idea that can reconcile the seemingly conflicting data sets. Here, an inverse relationship between genetic diversity and epigenetic complexity was deduced from a simple intuition in building complex systems. Genetic diversity, i.e., genetic distance or dissimilarity in DNA or protein sequences between individuals or species, is restricted by the complexity of epigenetic programs. This inverse relationship logically deduces the maximum genetic diversity hypothesis, which suggests that macroevolution from simple to complex organisms involves a punctuational increase in epigenetic complexity that in turn causes a punctuational loss in genetic diversity. The hypothesis explains a diverse set of biological phenomena, including both for and against the correlation between genetic distance and time of divergence.
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    LITERACY FOR LEARNING IN FURTHER EDUCATION IN THE UK: A SYMPOSIUM

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    The Literacies for Learning in Further Education (LfLFE) project, a collaboration between two universities – Stirling and Lancaster – and four further education colleges – Anniesland, Perth, Lancaster and Morecambe, and Preston, funded for three years from January 2004 as part of Phase 3 of the TLRP. The project draws on work already done on literacy practices engaged in by people in schools, higher education and the community and seeks to extend the insights gained from these studies into further education. It aims to explore the literacy practices of students and those practices developed in different parts of the curriculum and develop pedagogic interventions to support students’ learning more effectively. This project involves examining literacy across the many domains of people’s experiences, the ways in which these practices are mobilised and realised within different domains and their capacity to be mobilised and recontextualised elsewhere to support learning. A project such as this raises many theoretical, methodological and practical challenges, not least in ensuring validity across four curriculum areas in four sites drawing upon the collaboration of sixteen practitioner researchers. This symposium of four papers examines some of the challenges and findings from the first eighteen months of the project. The first paper explores some of the findings regarding students’ literacy practices in their everyday lives and those required of them in their college studies. The second focuses on one approach adopted by the project as a method through which to elicit student literacy practices. The other two papers focus on different aspects of partnership within the project, in particular the attempts to enable students and lecturers to be active researchers rather than simply respondent

    First-Order Logic Foundation of Relativity Theories

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    Motivation and perspective for an exciting new research direction interconnecting logic, spacetime theory, relativity--including such revolutionary areas as black hole physics, relativistic computers, new cosmology--are presented in this paper. We would like to invite the logician reader to take part in this grand enterprise of the new century. Besides general perspective and motivation, we present initial results in this direction.Comment: 25 pages, 4 figure

    Laser frequency combs for astronomical observations

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    A direct measurement of the universe's expansion history could be made by observing in real time the evolution of the cosmological redshift of distant objects. However, this would require measurements of Doppler velocity drifts of about 1 centimeter per second per year, and astronomical spectrographs have not yet been calibrated to this tolerance. We demonstrate the first use of a laser frequency comb for wavelength calibration of an astronomical telescope. Even with a simple analysis, absolute calibration is achieved with an equivalent Doppler precision of approximately 9 meters per second at about 1.5 micrometers - beyond state-of-the-art accuracy. We show that tracking complex, time-varying systematic effects in the spectrograph and detector system is a particular advantage of laser frequency comb calibration. This technique promises an effective means for modeling and removal of such systematic effects to the accuracy required by future experiments to see direct evidence of the universe's putative acceleration.Comment: Science, 5th September 2008. 18 pages, 7 figures (7 JPG files), including Supporting Online Material. Version with higher resolution figures available at http://astronomy.swin.edu.au/~mmurphy/pub.htm

    The present moment in quantum cosmology: challenges to the arguments for the elimination of time

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    Barbour, Hawking, Misner and others have argued that time cannot play an essential role in the formulation of a quantum theory of cosmology. Here we present three challenges to their arguments, taken from works and remarks by Kauffman, Markopoulou and Newman. These can be seen to be based on two principles: that every observable in a theory of cosmology should be measurable by some observer inside the universe, and all mathematical constructions necessary to the formulation of the theory should be realizable in a finite time by a computer that fits inside the universe. We also briefly discuss how a cosmological theory could be formulated so it is in agreement with these principles.Comment: This is a slightly revised version of an essay published in Time and the Instant, Robin Durie (ed.) Manchester: Clinamen Press, 200
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