Diluted antiferromagnets in a field seem to be in a different universality class than the random-field Ising model

We perform large-scale Monte Carlo simulations using the Machta-Newman-Chayes algorithms to study the critical behavior of both the diluted antiferromagnet in a field with 30% dilution and the random-field Ising model with Gaussian random fields for different field strengths. Analytical calculations by Cardy [Phys. Rev. B 29, 505 (1984)] predict that both models map onto each other and share the same universality class in the limit of vanishing fields. However, a detailed finite-size scaling analysis of both the Binder cumulant and the two-point finite-size correlation length suggests that even in the limit of small fields, where the mapping is expected to work, both models are not in the same universality class. Therefore, care should be taken when interpreting (experimental) data for diluted antiferromagnets in a field using the random-field Ising model. Based on our numerical data, we present analytical expressions for the phase boundaries of both models.Comment: 12 pages, 9 figures, 5 table

Critical behavior of the Random-Field Ising model at and beyond the Upper Critical Dimension

The disorder-driven phase transition of the RFIM is observed using exact ground-state computer simulations for hyper cubic lattices in d=5,6,7 dimensions. Finite-size scaling analyses are used to calculate the critical point and the critical exponents of the specific heat, magnetization, susceptibility and of the correlation length. For dimensions d=6,7 which are larger or equal to the assumed upper critical dimension, d_u=6, mean-field behaviour is found, i.e. alpha=0, beta=1/2, gamma=1, nu=1/2. For the analysis of the numerical data, it appears to be necessary to include recently proposed corrections to scaling at and beyond the upper critical dimension.Comment: 8 pages and 13 figures; A consise summary of this work can be found in the papercore database at http://www.papercore.org/Ahrens201

Tell Bleibil, Jordanien. Grabungen am Tell Bleibil im südlichen Jordantal. Die Arbeiten der Jahre 2020 und 2021

Nach der COVID-19-pandemiebedingten Unterbrechung der Feldforschungen im Jahr 2020 wurden 2021 am Tell Bleibil im Bereich der Nordflanke des Tells neue Testschnitte angelegt, die einen Teil eines außergewöhnlich gut erhaltenen Kasemattenmauerwerks aus der Eisenzeit IIB–C (spätes 9./frühes 8.–spätes 7./frühes 6. Jh. v. Chr.), genannt »Gebäude A«, freilegen konnten. In der Feldkampagne 2021 konnten von der Lehmziegelstruktur ingesamt zwei Räume ausgegraben werden. Die Strukturen lassen sich architektonisch und funktional den massiven Steinfundamenten der bereits in der Kampagne 2019 freigelegten eisenzeitlichen Befestigungsmauer an der Nordwestflanke des Tells zuordnen. Nach einem massiven Großbrand, der das Gebäude zerstörte und diese Phase beendete, wurde die Stätte während der persischen Periode neu besiedelt. Neben der archäologischen Arbeit wurde der Fundort zudem erstmalig komplett topographisch aufgenommen

Wadi Shuʿaib, Jordanien: Das Wadi Shuʿaib Archaeological Survey Project – Archäologische Forschungen zwischen Jordantal und transjordanischem Hochland

The Wadi Shuʿaib Archaeological Survey Project (WSAS) was initiated in2016. During the fall of 2016, a first preliminary survey campaign was conductedin the region of the Wadi Shuʿaib, stretching from the town of as-Saltin the northwest to the Jordan Valley (Shuna South) in the southwest of CentralJordan. During the first survey campaign, altogether fourteen archaeologicalsites were recorded, most of which were hitherto unknown, while otherswere already known to the scholarly community, but never recorded and documentedthoroughly. The aim of the survey in future campaigns is to recordall archaeological sites in this micro region connecting the fertile Jordan Valleywith the Transjordanian Highlands

Timing is Money - Evaluating the Effects of Early Availability of Feature Films via Video on Demand

Based on survey data from 489 German potential Video On Demand users this research explores effects of early movie availability on consumers’ utility, their willingness to pay, and copyright violations. Using a triangulation approach, we employed adaptive conjoint analysis and contingent valuation methodologies. Our results show substantially increased utility levels and greater willingness to pay for Video On Demand services that offer movies simultaneously with or shortly before the first official theatrical release. Our findings bear similarities to results from experiments on hyperbolic discounting, a concept from the field of behavioral economics. Diverging from classic microeconomic theory, immediate consumption seems to be valued irrationally high. This effect is even stronger for copyright violators. Implications both for future academic research and for the motion picture industry are drawn

Critical behavior of the Random-Field Ising Magnet with long range correlated disorder

We study the correlated-disorder driven zero-temperature phase transition of the Random-Field Ising Magnet using exact numerical ground-state calculations for cubic lattices. We consider correlations of the quenched disorder decaying proportional to r^a, where r is the distance between two lattice sites and a<0. To obtain exact ground states, we use a well established mapping to the graph-theoretical maximum-flow problem, which allows us to study large system sizes of more than two million spins. We use finite-size scaling analyses for values a={-1,-2,-3,-7} to calculate the critical point and the critical exponents characterizing the behavior of the specific heat, magnetization, susceptibility and of the correlation length close to the critical point. We find basically the same critical behavior as for the RFIM with delta-correlated disorder, except for the finite-size exponent of the susceptibility and for the case a=-1, where the results are also compatible with a phase transition at infinitesimal disorder strength. A summary of this work can be found at the papercore database at www.papercore.org.Comment: 9 pages, 13 figure

Real-Space, Real-Time Approach to Quantum-Electrodynamical Time-Dependent Density Functional Theory

The Quantum-Electrodynamical Time-Dependent Density Functional Theory (QED-TDDFT) equations are solved by time propagating the wave function on a tensor product of a Fock-space and real-space grid. Applications for molecules in cavities show the accuracy of the approach. Examples include the coupling strength and light frequency dependence of the energies, wave functions, optical absorption spectra, and Rabi splitting magnitudes in cavities, as well as a description of high harmonic generation in cavities