8,223 research outputs found

    Transient Nucleation near the Mean-Field Spinodal

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    Nucleation is considered near the pseudospinodal in a one-dimensional ϕ4\phi^4 model with a non-conserved order parameter and long-range interactions. For a sufficiently large system or a system with slow relaxation to metastable equilibrium, there is a non-negligible probability of nucleation occurring before reaching metastable equilibrium. This process is referred to as transient nucleation. The critical droplet is defined to be the configuration of maximum likelihood that is dynamically balanced between the metastable and stable wells. Time-dependent droplet profiles and nucleation rates are derived, and theoretical results are compared to computer simulation. The analysis reveals a distribution of nucleation times with a distinct peak characteristic of a nonstationary nucleation rate. Under the quench conditions employed, transient critical droplets are more compact than the droplets found in metastable equilibrium simulations and theoretical predictions.Comment: 7 Pages, 5 Figure

    Comments on "There is no axiomatic system for the quantum theory"

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    In a recent paper, Nagata [1] claims to derive inconsistencies from quantum mechanics. In this paper, we show that the inconsistencies do not come from quantum mechanics, but from extra assumptions about the reality of observables

    Intense CIII] 1907,1909 emission from a strong Lyman continuum emitting galaxy

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    We have obtained the first complete ultraviolet (UV) spectrum of a strong Lyman continuum(LyC) emitter at low redshift -- the compact, low-metallicity, star-forming galaxy J1154+2443 -- with a Lyman continuum escape fraction of 46% discovered recently. The Space Telescope Imaging Spectrograph spectrum shows strong Lya and CIII] 1909 emission, as well as OIII] 1666. Our observations show that strong LyC emitters can have UV emission lines with a high equivalent width (e.g. EW(CIII])=11.7±2.9A˚=11.7 \pm 2.9 \AA rest-frame), although their equivalent widths should be reduced due to the loss of ionizing photons. The intrinsic ionizing photon production efficiency of J1154+2443 is high, log⁥(Οion0)=25.56\log(\xi_{\rm ion}^0)=25.56 erg−1^{-1} Hz, comparable to that of other recently discovered z∌0.3−0.4z \sim 0.3-0.4 LyC emitters. Combining our measurements and earlier determinations from the literature, we find a trend of increasing Οion0\xi_{\rm ion}^0 with increasing CIII] 1909 equivalent width, which can be understood by a combination of decreasing stellar population age and metallicity. Simple ionization and density-bounded photoionization models can explain the main observational features including the UV spectrum of J1154+2443.Comment: 5 pages, 4 figures. Accepted for publication in A&A Letter
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