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Daniel?ArteagaEmail author Renaud?Parentani Enric?Verdaguer 《International Journal of Theoretical Physics》2005,44(10):1665-1689
We analyse a three-field model, which describes a relativistic two-level atom interactingwith a radiation bath. From the one-loop
retarded propagators at finite temperature we extract the transition rates and the modifications of the dispersion relations.
To further investigate the relationships between propagators and these physical quantities, we analyse a non-equilibrium situation
in which an additional atom is present in the bath. Preliminary results indicate that transition rates can still be extracted
from the (retarded) propagator. This approach couldtherefore be useful in relating high-frequency (trans-Planckian) dispersion
relations to the physical processes occurring at these scales. 相似文献
54.
Criteria are given for polynomials of the type Xn + aX3 + bX2 + cX + d, to have Galois group over any finite number field isomorphic to An. We use them to construct, for every n, infinitely many polynomials with absolute Galois group isomorphic to An, covering so, the case n even, , for which explicit equations were not known. 相似文献
55.
Cabana J Ling CD Oró-Solé J Gautier D Tobías G Adams S Canadell E Palacín MR 《Inorganic chemistry》2004,43(22):7050-7060
Antifluorite-type lithium chromium oxide nitrides were prepared by solid-state reaction of Li(3)N, Li(2)O, and Cr(2)N. Depending on the reaction time and starting Li/Cr and O/Cr ratios, either an ordered or a disordered phase (or mixtures of both) is obtained. The formation of the former is favored by short reaction times and low Cr/O ratios whereas the formation of the latter is favored by higher Cr/O ratios and longer reaction times. The two phases were characterized, and the first one was confirmed to be the already reported Li(14)Cr(2)N(8)O phase, whereas the stoichiometry of the second is Li(10)CrN(4)O(2). Interestingly, even if both contain cationic vacancies in the structure, electrochemical lithium intercalation could only be achieved for Li(10)CrN(4)O(2). This phase exhibits a reversible capacity of 160 mAh/g very stable upon cycling. Bond valence and first-principles DFT calculations were carried out to understand the absence of lithium insertion in Li(14)Cr(2)N(8)O. Li-Li repulsion and destabilization of the tetrahedral CrN(4) units induced by occupation of the potential sites, as well as the absence of energetically favorable pathways for transport of the ions to these sites, are suggested to be the reasons. 相似文献
56.
Interaction with the environment may induce stochastic semiclassical dynamicsin open quantum systems. In the gravitational context, stress-energy fluctuationsof quantum matter fields give rise to a stochastic behavior in the spacetimegeometry. The Einstein—Langevin equation is a suitable tool to take these effectsinto account when addressing the backreaction problem in semiclassical gravity.We analyze within this framework the generation of gravitational fluctuationsduring inflation, which are of great interest for large-scale structure formationin cosmology. 相似文献
57.
Herein, we investigated the viability of two group additivity methods for predicting Gibbs energies of a set of uranyl complexes. In first place, we proved that both density functional theory (DFT)-based methods and Serezhkin's stereoatomic model provide equivalent answers in terms of stability. Moreover, we proposed a novel methodology based on Mayer's population analysis for estimating Serezhkin's empirical parameters theoretically. On the other hand, we showed that Cheong and Persson linear algebra methodology can be successfully applied to uranyl complexes, and analyzed its performance in connection with the chemical nature of the compounds employed in the model. 相似文献
58.
Cabrera Edgar J. Amade Roger Jaller Lina Pascual Esther Bertran Enric 《Journal of nanoparticle research》2014,16(1):1-7
The thermal stability of nanocrystalline 3R-CuCrO2 obtaining by hydrothermal method was investigated by annealing treatment, XRD, FT-IR, XPS and TG. The three temperature domains corresponding to thermal stability of 3R-CuCrO2 nanocrystals (25–400 °C), destabilization of nanocrystalline 3R-CuCrO2 phase (400–800 °C) and recrystallization of 3R-CuCrO2 in microcrystalline state over 800 °C, were determined by the specific hydrothermal synthesis conditions. This study has indicated that nanocrystals with delafossite structure synthesized by hydrothermal method exhibit nanocrystalline state up to a reasonably high temperature, about 390 °C, which could be interesting for technical applications and the classical theory of the grain growth. 相似文献
59.
The most general Einstein-Rosen solutions obtainable by the inverse scattering transform, using the Levi-Cività metric as seed are analyzed. They can be classified as a family of evolving metrics without a clear physical interpretation and a family representing gravitational waves absorbed and radiated by a massive cylinder. The physical interpretation is based on a perturbative analysis, which shows that the solition waves have a peculiar superluminal effect, on the evaluation of the optical scalars and on Thorne's C energy.Work partially supported by research project CAICYT no. 0534/81. 相似文献