458 research outputs found

    Cell Microtubules as Cavities: Quantum Coherence and Energy Transfer?

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    A model is presented for dissipationless energy transfer in cell microtubules due to quantum coherent states. The model is based on conjectured (hydrated) ferroelectric properties of microtubular arrangements. Ferroelectricity is essential in providing the necessary isolation against thermal losses in thin interior regions, full of ordered water, near the tubulin dimer walls of the microtubule. These play the role of cavity regions, which are similar to electromagnetic cavities of quantum optics. As a result, the formation of (macroscopic) quantum coherent states of electric dipoles on the tubulin dimers may occur. Some experiments, inspired by quantum optics, are suggested for the falsification of this scenario.Comment: 7 pages LATEX. Invited talk at the 2000 International Conference on Mathematics and Engineering Techniques in Medicine and Biological Sciences, Monte Carlo Resort, Las Vegas (USA), June 26-29 2000, published in the proceeding

    Dark Energy as an off-shell Tachyon Background in four-dimensional Strings

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    We consider a time-dependent bosonic string in graviton, dilaton and tachyon backgrounds, for which it was already shown that conformal invariance is respected to all orders in alpha' and in any space-time dimension. Assuming that the tachyon is off-shell, we show in this note that the specific time-homogeneity of the corresponding space time effective action leads to a power-law expanding Universe, that can be accelerating or decelerating, depending on the range of parameter space considered. We interpret this result as dark energy. We arrive at this result without requiring the knowledge of the structure of the string effective action, which is not known to all orders in alpha'. Moreover, in our approach, the background configurations are consistent in a four-dimensional space time, without any need for extra dimensions.Comment: 10 pages, typos correcte

    Existence Theorems for Hairy Black Holes in su(N) Einstein-Yang-Mills theories

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    We establish the existence of hairy black holes in su(N) Einstein-Yang-Mills theories, described by N-1 parameters, corresponding to the nodes of the gauge field functions.Comment: 64 pages, latex2e, minor changes on the nature of the parameters, version to appear in J. Math. Phy
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