Comment on "Domain Structure in a Superconducting Ferromagnet"

According to Faure and Buzdin [Phys. Rev. Lett. 94, 187202 (2005)], in a superconducting ferromagnet a domain structure with a period small compared with the London penetration depth can arise. They claim that this contradicts to the conclusion of Sonin [Phys. Rev. B, 66, 100504 (2002)] that ferromagnetic domain structure in the Meissner state of a superconducting ferromagnet is absent in equilibrium. This contradiction is imaginary, based on misinterpretation of the results of these two papers.Comment: 1 page, no figures, final version published in Phys.Rev.Let

Critical dynamics of diluted relaxational models coupled to a conserved density (diluted model C)

We consider the influence of quenched disorder on the relaxational critical dynamics of a system characterized by a non-conserved order parameter coupled to the diffusive dynamics of a conserved scalar density (model C). Disorder leads to model A critical dynamics in the asymptotics, however it is the effective critical behavior which is often observed in experiments and in computer simulations and this is described by the full set of dynamical equations of diluted model C. Indeed different scenarios of effective critical behavior are predicted.Comment: 4 pages, 5 figure

Paramagnetic-diamagnetic interplay in quantum dots for non-zero temperatures

In the usual Fock-and Darwin-formalism with parabolic potential characterized by the confining energy \eps_o := \hbar\omega_o= 3.37 meV, but including explicitly also the Zeeman coupling between spin and magnetic field, we study the combined orbital and spin magnetic properties of quantum dots in a two-dimensional electron gas with parameters for GaAs, for N =1 and N >> 1 electrons on the dot. For N=1 the magnetization M(T,B) consists of a paramagnetic spin contribution and a diamagnetic orbital contribution, which dominate in a non-trivial way at low temperature and fields rsp. high temperature and fields. For N >> 1, where orbital and spin effects are intrinsically coupled in a subtle way and cannot be separated, we find in a simplified Hartree approximation that at N=m^2, i.e. at a half-filled last shell, M(T,B,N) is parallel (antiparallel) to the magnetic field, if temperatures and fields are low enough (high enough), whereas for N\ne m^2 the magnetization oscillates with B and N as a T-dependent periodic function of the variable x:=\sqrt{N}eB/(2m^*c\omega_o), with T-independent period \Delta x =1 (where m^* := 0.067 m_o is the small effective mass of GaAs, while m_o is the electron mass). Correspondingly, by an adiabatic demagnetization process, which should only be fast enough with respect to the slow transient time of the magnetic properties of the dot, the temperature of the dot diminishes rsp. increases with decreasing magnetic field, and in some cases we obtain quite pronounced effects.Comment: LaTeX, 28 pages; including three .eps-figures; final version accepted by J. Phys. CM, with minimal changes w.r.to v

Is Using Ornaments Still a Crime? Package Design Complexity and Brand Perception with Application to Champagne Labels

This article investigates the impact of the package design complexity on brand perception. This variable is particularly interesting because it is a choice which must be done by each brand manager no matter the product category. The packaging has been studied in many ways, and we already know its importance. A lot of existing researches are focused on the importance of its shape, its colours or its letter type. But only few studies have been done about the impact of the stylistic choice between simple and complex design on the brand perception. Furthermore, the consumer behaviour and design research both agree that the degree of simplicity of the packaging design has a significant impact on consumer’s attitudes towards a brand. In the case of this study, we defined two overall stylistic trends which come from the art literature: simple design versus overloaded design. In order to study the impact of the complexity degree, we created three labels: two representing the previously exposed styles and another one to study the relevance of a medium-loaded design. These labels were created in partnership with a printing company, present in Champagne since 1910. The three labels have the same text but different graphic designs in order to vary the degree of simplicity/complexity of the packaging observed on the market. Then, they were tested among 305 consumers according to a between-subjects experiment. The results allow the verification of different proposals from the literature: previous researches show that a simple design communicates an authentic and honest value which is also demonstrated in our study as the bottle with the simplest design is perceived as the most successful. Also, the bottle with an overloaded design is perceived as cheerful, imaginative and feminine as demonstrated by previous researches. This study demonstrates a significant impact of the package design’s level of simplicity on the brand perception as well as on consumer’s buying choices

The IIASA Energy-Multi Criteria Analysis Tool (ENE-MCA)

Researchers at the International Institute for Applied Systems Analysis (IIASA), building on work carried out within the framework of the Global Energy Assessment (GEA), have developed an interactive web-based scenario analysis tool that permits the concurrent assessment of synergies and trade-offs between multiple energy objectives at the global scale. This software, known as the IIASA Energy-Multi Criteria Analysis Policy Tool (ENE-MCA), is designed to assist national policy makers in their strategic policy planning processes. The tool extends work undertaken for the GEA and, as such, is built on the extensive set of global energy and environmental scenarios that have been generated as part of the GEA process. This document serves as an introduction to the ENE-MCA tool and as a brief manual for the typical user

Inclusive climate change mitigation and food security policy under 1.5°C climate goal

Climate change mitigation to limit warming to 1.5°C or well below 2°C, as suggested by the Paris Agreement, can rely on large-scale deployment of land-related measures (e.g., afforestation, or bioenergy production). This can increase food prices, and hence raises food security concerns. Here we show how an inclusive policy design can avoid these adverse side-effects. Food-security support through international aid, bioenergy tax, or domestic reallocation of income can shield impoverished and vulnerable people from the additional risk of hunger that would be caused by the economic effects of policies narrowly focussing on climate objectives only. In absence of such support, 35% more people might be at risk of hunger by 2050 (i.e. 84 million additional people) in a 2°C-consistent scenario. The additional global welfare changes due to inclusive climate policies are small (<0.1%) compared to the total climate mitigation cost (3.7% welfare loss), and the financial costs of international aid amount to about half a percent of high-income countries' GDP. This implies that climate policy should treat this issue carefully. Although there are challenges to implement food policies, options exist to avoid the food security concerns often linked to climate mitigation

Absence of Meissner State and Robust Ferromagnetism in the Superconducting State of UCoGe: Possible Evidence of Spontaneous Vortex State

We report ac magnetic susceptibility and dc magnetization measurements on the superconducting ferromagnet UCoGe (with superconducting and Curie temperatures of $T_{{\rm SC}} \sim 0.5$~K and $T_{{\rm Curie}} \sim 2.5$~K, respectively). In the normal, ferromagnetic state ($T_{{\rm SC}} < T < T_{{\rm Curie}}$), the magnetization curve exhibits a hysteresis loop similar to that of a regular itinerant ferromagnet. Upon lowering the temperature below $T_{{\rm SC}}$, the spontaneous magnetization is unchanged, but the hysteresis is markedly enhanced. Even deeply inside the superconducting state, ferromagnetism is not completely shielded, and there is no Meissner region, a magnetic field region of $H < H_{\rm c1}$ (a lower critical field). From these results, we suggest that UCoGe is the first material in which ferromagnetism robustly survives in the superconducting state and a spontaneous vortex state without the Meissner state is realized.Comment: 5 pages, 4 figures, to be published in J. Phys. Soc. Jp