12,395 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
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