592 research outputs found

    Fermionic determinant for SU(N) caloron with nontrivial holonomy

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    In the finite-temperature Yang-Mills theory we calculate the functional determinant for fermions in the fundamental representation of the SU(N) in the background of an instanton with non-trivial values of the Polyakov line at spatial infinity. This object, called the Kraan--van Baal -- Lee--Lu caloron, can be viewed as composed of N Bogomolny--Prasad--Sommerfeld monopoles (or dyons). We compute analytically two leading terms of the fermionic determinant at large separations between dyons.Comment: 17 pages, 2 figures, grammar corrections, introduction revise

    Modelling the abundance of 18O18O in the atmosphere and its sensitivity to temperature and ozone photochemistry

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    Atmospheric temperature and ozone photochemistry are recognised to play dominant roles in setting the abundance of 18O18O isotopologues (expressed via Δ36) of atmospheric oxygen. Here, we use the AC-GCM EMAC to simulate the abundance of atmospheric 18O18O in a most consistent to date kinetic chemistry modelling framework. Extensive model diagnostics allow us quantifying contribution of various factors into changes in Δ36 since the last 60 years. It is shown that atmospheric dynamics is another fundamental ingredient of atmospheric Δ36 distribution. We discuss potential applications of clumped O2 composition for quantifying various atmospheric processes like decadal changes in tropospheric O3 abundance or tropopause warming due to volcanism

    Fermionic determinant for dyons and instantons with nontrivial holonomy

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    We calculate exactly the functional determinant for fermions in fundamental representation of SU(2) in the background of periodic instanton with non-trivial value of the Polyakov line at spatial infinity. The determinant depends on the value of the holonomy v, the temperature, and the parameter r_12, which at large values can be treated as separation between the Bogomolny--Prasad--Sommerfeld monopoles (or dyons) which constitute the periodic instanton. We find a compact expression for small and large r_12 and compute the determinant numerically for arbitrary r_12 and v.Comment: 17 pages, published version, references adde

    Northward expansion of the westerlies over glacial southeastern Australia: evidence from semi-arid lunette dunes, temperate basalt plains, and wind modelling

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    It has long been hypothesized that the last glacial maximum (LGM) oversaw cold, arid, windy climates across southern Australia, and that these were driven by intensification and northward expansion of mid-latitude westerly circulation. Moreover, it was recently suggested that Australia experienced an extended LGM which began several millennia before the global peak. Aeolian sedimentary deposits provide key evidence for these hypotheses, and climate modelling an alternative means to test them. As yet, however, combined approaches to reconstructing glacial environments on the continent are scarce. Here we provide new evidence for westerly wind regimes across glacial southeastern Australia. We confirm active transverse lunette deposition at c. 29 ka and c. 23–19 ka in the semi-arid Willandra Lakes, and identify aeolian sand incursions to Spring Creek on the temperate Western Victorian Volcanic Plains from c. 29 ka. The Spring Creek deposits contain a surprising quantity of sand-sized quartz given the basalt setting, which we propose to be allochthonous and likely transported some distance. The site lies more than 50 km east and south of dunefields which were active at the same time and may have contributed sediment via long distance transport. We investigate the hypothesis for northward glacial expansion of westerly winds by combining our sediment records with aeolian particle transport simulations. We find that LGM near-surface winds were dominated by stronger, more focussed westerly air flow across southeastern Australia, compared with presently more diffuse wind regimes. Our results suggest stronger potential for LGM eastward distal sand transport onto the basalt plains, coeval with enhanced aeolian activity in the semi-arid Australian dunefields. Our combined reconstruction of aeolian deposition and trajectory modelling confirms the extended LGM hypothesis and indicates a northward migration of westerly winds over southeastern Australia during this period

    Thermodynamic Bethe Ansatz for the AdS_5 x S^5 Mirror Model

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    We use the string hypothesis for the mirror theory to derive the Thermodynamic Bethe Ansatz equations for the AdS_5 x S^5 mirror model. We further demonstrate how these equations can be used to construct the associated Y-system recently discussed in the literature, putting particular emphasis on the assumptions and the range of validity of the corresponding construction.Comment: 31 pages, LaTex, v2: references added, v3: published versio

    Morphology of the surface of technically pure titanium VT1-0 after electroexplosive carbonization with a weighed zirconium oxide powder sample and electron beam treatment

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    Titanium is carbonized by the electroexplosive method. Formation of a surface alloyed layer and a coating on the treated surface is established by the methods of transmission electron microscopy. The morphology and elemental composition of the alloyed layer are analyzed. A dependence of the structure of the modified layer subjected to electron gun treatment on the absorbed power density is revealed

    Temperature quantization from the TBA equations

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    We analyze the Thermodynamic Bethe Ansatz equations for the mirror model which determine the ground state energy of the light-cone AdS_5 x S^5 superstring living on a cylinder. The light-cone momentum of string is equal to the circumference of the cylinder, and is identified with the inverse temperature of the mirror model. We show that the natural requirement of the analyticity of the Y-functions leads to the quantization of the temperature of the mirror model which has never been observed in any other models.Comment: 1+14 pages, v2: a paragraph added in section 2.

    Acid-Base Properties Of Glass Substrate And SiO[2]-Bi[2]O[3]Thin-Film Systems Obtained On It

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    The article describes an experimental research as a result of which SiO[2]–Bi[2]O[3] films have been synthesized of film-forming solutions based on tetraethoxysilane and bismuth nitrate (III). Acid-base properties of a glass substrate and SiO[2]–Bi[2]O[3] films obtained on it have been studied. The dependency of physical and chemical properties of SiO[2]–Bi[2]O[3] composites on their percentage composition have been revealed
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