12,023 research outputs found

    Field-control, phase-transitions, and life's emergence

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    Instances of critical-like characteristics in living systems at each organizational level as well as the spontaneous emergence of computation (Langton), indicate the relevance of self-organized criticality (SOC). But extrapolating complex bio-systems to life's origins, brings up a paradox: how could simple organics--lacking the 'soft matter' response properties of today's bio-molecules--have dissipated energy from primordial reactions in a controlled manner for their 'ordering'? Nevertheless, a causal link of life's macroscopic irreversible dynamics to the microscopic reversible laws of statistical mechanics is indicated via the 'functional-takeover' of a soft magnetic scaffold by organics (c.f. Cairns-Smith's 'crystal-scaffold'). A field-controlled structure offers a mechanism for bootstrapping--bottom-up assembly with top-down control: its super-paramagnetic components obey reversible dynamics, but its dissipation of H-field energy for aggregation breaks time-reversal symmetry. The responsive adjustments of the controlled (host) mineral system to environmental changes would bring about mutual coupling between random organic sets supported by it; here the generation of long-range correlations within organic (guest) networks could include SOC-like mechanisms. And, such cooperative adjustments enable the selection of the functional configuration by altering the inorganic network's capacity to assist a spontaneous process. A non-equilibrium dynamics could now drive the kinetically-oriented system towards a series of phase-transitions with appropriate organic replacements 'taking-over' its functions.Comment: 54 pages, pdf fil

    Interlinked 3D and 4D 3-Quark Wave Functions in a Bethe-Salpeter Model

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    Using the method of Green's functions within the framework of a Bethe-Salpeter formalism characterized by a pairwise qqqq interaction with a 3D support to its kernel (expressed in a Lorentz-covariant manner), the 4D BS wave function for a system of three identical relativistic spinless quarks is reconstructed from the corresponding 3D form which satisfies a {\it fully connected} 3D BSE. This result is a 3-body generalization of a similar interconnection between the 3D and 4D 2-body wave functions that had been found earlier under identical conditions of a 3D support to the corresponding BS kernel, using the ansatz of Covariant Instaneity for the pairwise qqˉq\bar q interaction. The generalization from spinless to fermion quarks is straightforward.Comment: 13 pages, Latex. e.mail: [email protected]

    Can Environmental Decoherence be Reversed for an Open Quantum System in a Magnetic field ?

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    A simple model is considered for an open system consisting of an aggregation of magnetic particles (like greigite) in the presence of a magnetic field (H), and interacting linearly with a bath of 3D harmonic oscillators. Using the Feynman-Vernon formalism, as given in Weiss (termed FVW), the time-evolved reduced density matrix (after eliminating the bath d.o.f.'s), is examined for environmental decoherence as defined in the FVW formalism. While decoherence is usually positive for most two-way couplings with the enviroment, it is found that a three−waythree-way interaction involving the system plus bath plus H-field all together, can facilitate a reversalreversal of sign of this quantity! This may have implications for quantum coherence based phenomena on the origins of life.Comment: 8 pages on pd

    Minimum Of QCD Effective Action As Test Of QCD Confinement Parameter

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    A new approach to the non-perturbative regime of QCD is proposed by introducing a (non-hermitian) field BB related to the usual gluon field AA by BμB_\mu = (1+σ∂m)Aμ(1+ \sigma \partial_m) A_\mu where mm goes to zero after differentiation, and σ\sigma is a parameter which `runs' with momentum (kk). An exact treatment yields a structure [1/k2+2μ2/k4][1/k^2 + 2\mu^2/k^4] for the gluon propagator, where σ2\sigma^2 =πk4/9μ2αs\pi k^4/9\mu^2\alpha_s, showing linearlinear confinement in the instantaneous limit. This propagator was recently employed to evaluate some basic condensates and their temperature dependence (in the cosmological context), which were all reproduced for μ=1GeV\mu = 1GeV (termed the `confinement scale parameter'), in association with the QCD scale parameter Λqcd=200MeV\Lambda_{qcd}= 200 MeV [hep-ph/0109278]. This paper seeks to provide a formal basis for the ratio Λqcd/μ\Lambda_{qcd} / \mu by employing the minimality condition for the integratedintegrated effective action Γ\Gamma, up to the 2-loop level, using the Cornwall-Jackiw formalism for composite operators. To that end the mass function m(p)m(p), determined via the Schwinger-Dyson equation (as a zero of the functional derivative of Γ\Gamma w.r.t SF′S_F'), acts as a feeder, and the stationarity condition on Γ\Gamma as function of μ\mu and αs(μ)\alpha_s(\mu) gives the ratio Λ/μ\Lambda /\mu = 0.246, in fair accord with the value 0.20 given above. Inclusion of a two-loop Γ\Gamma is crucial for the agreement. \\ Keywords: confinement scale, QCD effective action, minimality condition, BB-field.Comment: LaTex file, 12 pages on dv

    The Dimensions of Field Theory : From Particles to Strings

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    This is an editorial summary of the contents of a Book comprising a set of Articles by acknowledged experts dealing with the impact of Field Theory on major areas of physics (from elementary particles through condensed matter to strings), arranged subjectwise under six broad heads. The Book which emphasizes the conceptual, logical and formal aspects of the state of the art in these respective fields, carries a Foreword by Freeman Dyson, and is to be published by the Indian National Science Academy on the occasion of the International Mathematical Year 2000. The authors and full titles of all the Articles (33) are listed sequentially (in the order of their first appearance in the narration) under the bibliography at the end of this Summary, while a few of the individual articles to appear in the Book are already available on the LANL internet.Comment: LaTex file, 24 page
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