Low-lying fermion modes of Nf=2 improved Wilson fermions

We present preliminary results for the topological charge and susceptibility determined from the low-lying eigenmodes of the Wilson-Dirac operator. These modes have been computed on dynamical configurations with Nf=2 non-perturbatively improved Wilson fermions. We compare our results with the eigenmodes of fermions in the quenched approximation.Comment: Lattice2001(confinement), 3 pages, 5 Figure

Rural economic development in the post-agricultural era : policy recommendations

Present rural economies of developed countries are no more dominated by agriculture. However, in policies of rural economic development the position of farming remains very strong due to the persisiting pro - ductivist thinking. Consequently, the tools of such policies are strongly related to agriculture, despite its minor contribution to rural economies of developed countries. The aim of this article is to offer recommendations for more efficient policies of rural economic development which are not based only on agriculture. These policy re - commendations for European or national, regional and local authorities are key research findings of the project Non-agricultural and non-tourism economic industries in rural peripheries of the Visegrad countries funded by the International Visegrad Fund

Comparison of different Tidal Disruption Event light curve models with TiDE, a new modular open source code

A tidal disruption event (TDE) occurs when a supermassive black hole disrupts a nearby passing star by tidal forces. The subsequent fallback accretion of the stellar debris results in a luminous transient outburst. Modeling the light curve of such an event may reveal important information, for example the mass of the central black hole. This paper presents the TiDE software based on semi-analytic modeling of TDEs. This object-oriented code contains different models for the accretion rate and the fallback timescale $t_{\rm min}$. We compare the resulting accretion rates to each other and with hydrodynamically simulated ones and find convincing agreement for full disruptions. We present a set of parameters estimated with TiDE for the well-observed TDE candidate AT2019qiz, and compare our results with those given by the MOSFiT code. Most of the parameters are in reasonable agreement, except for the mass and the radiative efficiency of the black hole, both of which depend heavily on the adopted fallback accretion rate.Comment: 17 pages, 12 figures, 2 tables, accepted in PAS

Fitting optical light curves of Tidal Disruption Events with TiDE

A Tidal Disruption Event (TDE) occurs when a supermassive black hole tidally disrupt a nearby passing star. The fallback accretion rate of the disrupted star may exceed the Eddington limit, which induces a supersonic outflow and a burst of luminosity, similar to an explosive event. Thus, TDEs can be detected as very luminous transients, and the number of observations for such events is increasing rapidly. In this paper we fit 20 TDE light curves with TiDE, a new public, object-oriented code designed to model optical TDE light curves. We compare our results with those obtained by the popular MOSFiT and the recently developed TDEmass codes, and discuss the possible sources of differences.Comment: 14 pages, 4 figures, 4 tables, accepted in PAS

Remarks on the Gribov Problem in Direct Maximal Center Gauge

We review the equivalence of maximal center gauge fixing to the problem of finding the best fit, to a given lattice gauge field, by a thin vortex configuration. This fit is necessarily worst at the location of P-plaquettes. We then compare the fits achieved in Gribov copies generated by (i) over-relaxation; (ii) over-relaxation after Landau gauge preconditioning; and (iii) simulated annealing. Simulated annealing yields the best fit if all links on the lattice are included, but the situation changes if we consider only the lattice volume exterior to P-plaquettes. In this exterior region, the fit is best for Gribov copies generated by over-relaxation, and worst for Gribov copies generated after Landau gauge preconditioning. The two fitting criteria (including or not including the P-plaquettes) yield string tensions differing by -34% to +20% respectively, relative to the full string tension. Our usual procedure (``quenched minimization'') seems to be a compromise between these criteria, and yields string tensions at an intermediate value close to the full string tension.Comment: 14 pages, 6 figure

Pótlások Magyarország edényes növényfajainak elterjedési atlaszához III.

Jelen közleményünk annak a sorozatnak a harmadik része, melynek célja a Magyarország edényes növényfajainak elterjedési atlasza térképeinek kiegészítése, főként aktuális előfordulási adatokkal. Ezúttal 558 edényes taxon előfordulási adatait közöljük az ország szinte egész területéről (mintegy 186 flóratérképezési kvadrátból), de legnagyobb számban az Északi-középhegységből. Az adatok között ritkább őshonos taxonok (például Marsilea quadrifolia, Salicornia prostrata, Stellaria palustris, Potentilla patula, Althaea cannabina, Lythrum tribracteatum, Ajuga laxmannii, Plantago schwarzenbergiana, Alisma gramineum, Gagea bohemica, G. szovitsii), ritka, vagy legalábbis adathiányos idegenhonos fajok (például Chorispora tenella, Thladiantha dubia, Senecio vernalis) mellett országosan elterjedt, de többé-kevésbé alulreprezentált fajok (például Scleranthus annuus, Vicia hirsuta, V. lathyroides) esetében is közöljük az Atlasz térképeihez képest újnak bizonyuló lelőhelyeket. A legközönségesebb fajok esetében a lelőhelyek részletezése nélkül csupán KEF-kódokat adunk meg.</jats:p

Chiral symmetry restoration, eigenvalue density of Dirac operator and axial U(1) anomaly at finite temperature

We reconsider constraints on the eigenvalue density of the Dirac operator in the chiral symmetric phase of 2 flavor QCD at finite temperature. To avoid possible ultra-violet(UV) divergences, we work on a lattice, employing the overlap Dirac operator, which ensures the exact "chiral" symmetry at finite lattice spacings. Studying multi-point correlation functions in various channels and taking their thermodynamical limit (and then taking the chiral limit), we obtain stronger constraints than those found in the previous studies: both the eigenvalue density at the origin and its first and second derivatives vanish in the chiral limit of 2 flavor QCD. In addition we show that the axial U(1) anomaly becomes invisible in susceptibilities of scalar and pseudo scalar mesons, suggesting that the 2nd order chiral phase transition with the O(4) scaling is not realized in 2 flavor QCD. Possible lattice artifacts when non-chiral lattice Dirac operator is employed are briefly discussed.Comment: 39 pages, 1 figure(2 eps files), a version published in PR

Weak convergence of finite element approximations of linear stochastic evolution equations with additive noise II. Fully discrete schemes

We present an abstract framework for analyzing the weak error of fully discrete approximation schemes for linear evolution equations driven by additive Gaussian noise. First, an abstract representation formula is derived for sufficiently smooth test functions. The formula is then applied to the wave equation, where the spatial approximation is done via the standard continuous finite element method and the time discretization via an I-stable rational approximation to the exponential function. It is found that the rate of weak convergence is twice that of strong convergence. Furthermore, in contrast to the parabolic case, higher order schemes in time, such as the Crank-Nicolson scheme, are worthwhile to use if the solution is not very regular. Finally we apply the theory to parabolic equations and detail a weak error estimate for the linearized Cahn-Hilliard-Cook equation as well as comment on the stochastic heat equation

Quasi-phase-matching high-harmonic radiation using chirped THz pulses

High-order harmonic generation in the presence of a chirped THz pulse is investigated numerically with a complete 3D nonadiabatic model. The assisting THz pulse illuminates the high-order harmonic generation gas cell laterally inducing quasi-phase-matching. We demonstrate that it is possible to compensate the phase mismatch during propagation and extend the macroscopic cutoff of a propagated strong IR pulse to the single-dipole cutoff. We obtain 2 orders of magnitude increase in the harmonic efficiency of cutoff harmonics (170 eV) using a THz pulse of constant wavelength, and a further factor of 3 enhancement when a chirped THz pulse is use