Hubbard-model description of the high-energy spin-spectral-weight distribution in La(2)CuO(4)

The spectral-weight distribution in recent neutron scattering experiments on the parent compound La$_2$CuO$_4$ (LCO), which are limited in energy range to about 450\,meV, is studied in the framework of the Hubbard model on the square lattice with effective nearest-neighbor transfer integral $t$ and on-site repulsion $U$. Our study combines a number of numerical and theoretical approaches, including, in addition to standard treatments, density matrix renormalization group calculations for Hubbard cylinders and a suitable spinon approach for the spin excitations. Our results confirm that the $U/8t$ magnitude suitable to LCO corresponds to intermediate $U$ values smaller than the bandwidth $8t$, which we estimate to be $8t \approx 2.36$ eV for $U/8t\approx 0.76$. This confirms the unsuitability of the conventional linear spin-wave theory. Our theoretical studies provide evidence for the occurrence of ground-state d-wave spinon pairing in the half-filled Hubbard model on the square lattice. This pairing applies only to the rotated-electron spin degrees of freedom, but it could play a role in a possible electron d-wave pairing formation upon hole doping. We find that the higher-energy spin spectral weight extends to about 566 meV and is located at and near the momentum $[\pi,\pi]$. The continuum weight energy-integrated intensity vanishes or is extremely small at momentum $[\pi,0]$. This behavior of this intensity is consistent with that of the spin waves observed in recent high-energy neutron scattering experiments, which are damped at the momentum $[\pi,0]$. We suggest that future LCO neutron scattering experiments scan the energies between 450 meV and 566 meV and momenta around $[\pi,\pi]$.Comment: 23 pages, 5 figure

Charge Influence On Mini Black Hole's Cross Section

In this work we study the electric charge effect on the cross section production of charged mini black holes (MBH) in accelerators. We analyze the charged MBH solution using the {\it fat brane} approximation in the context of the ADD model. The maximum charge-mass ratio condition for the existence of a horizon radius is discussed. We show that the electric charge causes a decrease in this radius and, consequently, in the cross section. This reduction is negligible for protons and light ions but can be important for heavy ions.Comment: 4 pages, 0 figure. To be published in Int. J. Mod. Phys. D

Measures and model of the churches of São Miguel (Azores)

The religious spaces are carriers of great symbolic importance, standing out in the urban fabric not only for their location, but also for their scale in relation to the surrounding buildings. We show the relevance of the religious space in the São Miguel island (Azores) urban fabric, where the church presents itself as an element of great importance. It is the generator of the urban fabric, and it is usually strategically located as a landmark of the civic centre of the localities. This study presents an analysis of the main façades of the parish churches of the island of S. Miguel built during the eighteenth and nineteenth centuries. It highlights the existence of a typology of façade, which is a consequence of the materials and building systems existing there at the time. This demonstration continues the studies carried out by Sousa (1986) with the concept of façade “micaelense baroque ornamentation” and Caldas (2012) with the concept of “micaelense baroque façade” and “micaelense type façade”. Methodologically, the investigation was carried out through the analysis of the elements that make up the façades of the parish churches, the study of old and current photography, and drawings made in CAD; and the systematization of façades by grouping them into categories and establishing a typology between the various churches of the eighteenth and nineteenth centuries.info:eu-repo/semantics/publishedVersio

ScannerS: parameter scans in extended scalar sectors

We present the public code ScannerS–2 that performs parameter scans and checks parameter points in theories beyond the Standard Model (BSM) with extended scalar sectors. ScannerS incorporates theoretical and experimental constraints from many different sources in order to judge whether a parameter point is allowed or excluded at approximately 95% {CL}. The BSM models implemented in ScannerS include many popular BSM models such as singlet extensions, different versions of the Two-Higgs-Doublet Model, or the different phases of the Next-to Two-Higgs-Doublet Model. The ScannerS framework allows straightforward extensions by additional constraints and BSM models

Coupling and induced depinning of magnetic domain walls in adjacent spin valve nanotracks

The magnetostatic interaction between magnetic domain walls (DWs) in adjacent nanotracks has been shown to produce strong inter-DW coupling and mutual pinning. In this paper, we have used electrical measurements of adjacent spin-valve nanotracks to follow the positions of interacting DWs. We show that the magnetostatic interaction between DWs causes not only mutual pinning, as observed till now, but that a travelling DW can also induce the depinning of DWs in near-by tracks. These effects may have great implications for some proposed high density magnetic devices (e.g. racetrack memory, DW logic circuits, or DW-based MRAM).Comment: The following article has been accepted by the Journal of Applied Physic

Rheological and structural characterization of gels from whey protein hydrolysates/locust bean gum mixed systems

The gelling ability of whey proteins can be changed by limited hydrolysis and by the addition of other components such as polysaccharides. In this work the effect of the concentration of locust bean gum (LBG) on the heat-set gelation of aqueous whey protein hydrolysates (10% w/w) from pepsin and trypsin was assessed at pH 7.0. Whey protein concentrate (WPC) mild hydrolysis (up to 2.5% in the case of pepsin and 1.0% in the case of trypsin) ameliorates the gelling ability. The WPC synergism with LBG is affected by the protein hydrolysis. For a WPC concentration of 10% (w/w), no maximum value was found in the G′ dependence on LBG content in the case of the hydrolysates, unlike the intact WPC. However, for higher protein concentrations, the behaviour of gels from whey proteins or whey protein hydrolysates towards the presence of LBG becomes very similar. In this case, a small amount of LBG in the presence of salt leads to a big enhancement in the gel strength. Further increases in the LBG concentration led to a decrease in the gel strength

Scalar Casimir Effect on a D-dimensional Einstein Static Universe

We compute the renormalised energy momentum tensor of a free scalar field coupled to gravity on an (n+1)-dimensional Einstein Static Universe (ESU), RxS^n, with arbitrary low energy effective operators (up to mass dimension n+1). A generic class of regulators is used, together with the Abel-Plana formula, leading to a manifestly regulator independent result. The general structure of the divergences is analysed to show that all the gravitational couplings (not just the cosmological constant) are renormalised for an arbitrary regulator. Various commonly used methods (damping function, point-splitting, momentum cut-off and zeta function) are shown to, effectively, belong to the given class. The final results depend strongly on the parity of n. A detailed analytical and numerical analysis is performed for the behaviours of the renormalised energy density and a quantity `sigma' which determines if the strong energy condition holds for the `quantum fluid'. We briefly discuss the quantum fluid back-reaction problem, via the higher dimensional Friedmann and Raychaudhuri equations, observe that equilibrium radii exist and unveil the possibility of a `Casimir stabilisation of Einstein Static Universes'.Comment: 37 pages, 15 figures, v2: minor changes in sections 1, 2.5, 3 and 4; version published in CQ