93,270 research outputs found

    A note on the time evolution of the fission decay width under the influence of dissipation

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    The claim put forward in a recent paper by B. Jurado, K.-H. Schmidt and J. Benlliure that the transient effect of nuclear fission may be described simply as a relaxation process in the upright oscillator around the potential minimum is refuted. Some critical remarks on the relevance of this effect in general are added.Comment: 6 pages, LaTex, no figures; final, shorter version, to appear in PL

    Influence of microscopic transport coefficients on the formation probabilities for super-heavy elements

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    The formation probability is shown to increase by a few orders of magnitude if microscopic transport coefficients are used rather than those of the common macroscopic pictures. Quantum effects in collective dynamics are taken into account through the fluctuating force, as exhibited in diffusion coefficients for a Gaussian process. In the range of temperatures considered here, they turn out to be of lesser importance.Comment: 20 pages, 9 figures, replaced by revised version accepted for publication in NP

    Building suitable sets for locally compact groups by means of continuous selections

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    If a discrete subset S of a topological group G with the identity 1 generates a dense subgroup of G and S \cup {1} is closed in G, then S is called a suitable set for G. We apply Michael's selection theorem to offer a direct, self-contained, purely topological proof of the result of Hofmann and Morris on the existence of suitable sets in locally compact groups. Our approach uses only elementary facts from (topological) group theory.Comment: No changes except page layout. 11 pages. To appear in: Topology and its Application

    Spatial holeburning effects in the amplified spontaneous emission spectra of the non-lasing supermode in semiconductor laser arrays

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    The amplified spontaneous emission spectrum of the light field in the non-lasing supermode of two coupled semiconductor lasers is analyzed using linearized Langevin equations. It is shown that the interference betweeen the laser mode and the fluctuating light field in the non-lasing mode causes spatial holeburning. This effect introduces a phase sensitive coupling between the laser field and the fluctuations in the non-lasing mode. For high laser fields, this coupling splits the spectrum of the non-lasing mode into a triplet consisting of two relaxation oscillation sidebands which are in phase with the laser light and a center line at the lasing frequency with a phase shift of pi half relative to the laser light. As the laser intensity is increased close to threshold, the spectrum shows a continuous transition from the single amplified spontaneous emission line at the frequency of the laser mode to the triplet structure. An analytical expression for this transition is derived and typical features are discussed.Comment: 16 pages RevTex and 12 figures, discussion of carrier diffusion added, to be published in JOSA

    SU(2) and SU(3) Yang-Mills thermodynamics and some implications

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    We sketch the development of effective theories for SU(2) and SU(3) Yang-Mills thermodynamics. The most important results are quoted and some implications for particle physics and cosmology are discussed.Comment: 18 pages, 5 figures, v3: consequences of a change in the evolution equations for the effective couplings implemented, practically no change in the physics, erratum to appear in the journal-published versio
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