Archive for the ‘Physics and cosmology’ Category

Goldilocks Enigma

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The Goldilocks Enigma Paul Davies Davies’s book deals with the apparent ‘fine-tuning’ of the universe to render it suitable for organic life, and the problems that this produces for understanding the origin of the universe itself. In his preface, he discusses the anthropic principle, which is essentially the view that the structure of the universe is such as to make it suitable for life. Strictly, this proposition is the weak anthropic principle. The strong anthropic principle Read more […]

Time, energy & consciousness

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Time, Energy and Consciousness The physicist, Bernard Carr, recently put forward the suggestion that there might be a connection between the treatment of time and energy under Heisenberg’s uncertainty principle and the sense of a ‘present moment’ that encapsulates our consciousness, and is distinct from the past that has to be recalled from memory or the future which is the subject of thought or speculation. Uncertainty principle is better known for stating that the position and momentum of Read more […]

Thoughts on relativity

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Thoughts on relativity Based mainly on David Bohm and Roger Penrose While quantum theory has been censored out of much of popular thought and education, relativity has suffered the opposite fate of being popularised in a ‘wow! You wouldn’t guess that style’, with an arguable lack of balance as to what is most important in the theory. Mass-energy equivalence: It could be argued that mass-energy equivalence is of greater significance than more crowd-stopping ideas such as different time orderings. Read more […]

Temporally separated entanglement

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Entanglement between photons that have never coexisted Megidish, E. H. S. Eisenberg et al, University of Jerusalem arXiv:1209.4191v1 [quant ph] 19 Sep 2012 This study demonstrates that entanglement is not only between spatially separated quanta, but also between temporally separated quanta, or in other words it is extended across spacetime. This study utilises an experimental procedure from the 1990s known as entanglement swapping. The experiment involves two entangled pairs of photons, Read more […]

Superposition of wave and particle state

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Realisation of quantum Wheeler’s delayed-choice experiment Tang et al, University of Science & Technology of China Nature Photonics, 6, pp. 602-6, doi: 10.1038/nphoton.2012.179, 19 August 2012 Bohr’s complementarity principle proposed that quanta were either in a wave state or a particle state according to how an experiment was performed. Tang’s study was a refinement of Wheeler’s delayed choice experiment. In this only after a photon has passed through two slits or a beam splitter is Read more […]

Quantum and classical interaction

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Quantum and classical interaction Answering Descartes: Beyond Turing Stuart Kauffman, University of Vermont & Tampere University Kauffman is sceptical relative to ideas of consciousness based on classical and macroscopic physics. He proposes instead that consciousness is related to the border area between quantum and classical processing, where the non-algorithmic aspect of the quantum and the non-random aspect of the classical may be mixed. This is termed the ‘poised realm’, and is Read more […]

Spacetime and decisions

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Spacetime and decisions From the webmaster Keywords: Spacetime, decision-making, emotion, freewill There is something like a consensus in physics that spacetime is discrete rather than continuous. This would appear to mean that spacetime is something like a network or web having pattern, and therefore capable of representing or conveying information. Clearly there is no evolutionary advantage in expending energy accessing the spacetime level, if it only does the same kind of logic or Read more […]

Wave function collapse

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Nine Lives + One: Hello Kitty! New Scientist 12/05/07 Amanda Gefter Andrew Jordan of the University of Rochester has come up with a new take on the Schrödinger cat problem. Superposition is central to the problem. Experiments prove that superpositions do occur. But they are not apparent in the classical world, and there is a problem in deciding how and why things move from a superpositioned state to a single defined state. Jordan, working with Alexander Korotkov of the University of California Read more […]

Ghost in the atom

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Ghost in the atom Marcus Chown New Scientist, 28 July 2012 In quantum theory the wave function encodes all the possible behaviours of a quantum system and allows the calculation of the probability of finding a particle at any particular point in space. The tradition in quantum physics has been to regard the wave function as a convenient abstraction for the purpose of calculations, and as being just a probability distribution. The alternive is that the quantum wave is a real underlying Read more […]

Interpretations of quantum theory

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Physics: Interpretations of quantum theory Elegance and Enigma: Quantum Interviews Ed. Maximilian Schlosshauer Springer (2011) Keywords:  collapse theories, pilot-wave theories, decoherence, quantum information This book demonstrates that the different interpretations of quantum theory are becoming more distinct and more entrenched, rather than showing any sign of moving towards any kind of consensus. In particular, six types of approach are distinguished, (1.) Everett many-world Read more […]