Misleading signatures of quantum chaos

The main signature of chaos in a quantum system is provided by spectral statistical analysis of the nearest neighbor spacing distribution and the spectral rigidity given by $\Delta_3(L)$. It is shown that some standard unfolding procedures, like local unfolding and Gaussian broadening, lead to a spurious increase of the spectral rigidity that spoils the $\Delta_3(L)$ relationship with the regular or chaotic motion of the system. This effect can also be misinterpreted as Berry's saturation.Comment: 4 pages, 5 figures, submitted to Physical Review

Natural food colorants and preservatives: a review, a demand, and a challenge

The looming urgency of feeding the growing world population along with the increasing consumers’ awareness and expectations have driven the evolution of food production systems and the processes and products applied in the food industry. Although substantial progress has been made on food additives, the controversy in which some of them are still shrouded has encouraged research on safer and healthier next generations. These additives can come from natural sources and confer numerous benefits for health, beyond serving the purpose of coloring or preserving, among others. As limiting factors, these additives are often related to stability, sustainability, and cost-effectiveness issues, which justify the need for innovative solutions. In this context, and with the advances witnessed in computers and computational methodologies for in silico experimental aid, the development of new safer and more efficient natural additives with dual functionality (colorant and preservative), for instance by the copigmentation phenomena, may be achieved more efficiently, circumventing the current difficulties.The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) for financial support through national funds FCT/MCTES to CIMO (Grant UIDB/00690/2020); national funding by F.C.T. and P.I., through the Institutional Scientific Employment Program-Contract for C.P. and L.B. contracts and C.N. (Grant 2021.05369.BD) and A.K.M. (Grant 2020.06231.BD) Ph.D. grants. The authors acknowledge the FEDER-Interreg España-Portugal Programme for financial support through the Project TRANSCoLAB 0612_TRANS_CO_LAB_2_P; to ERDF through the Regional Operational Program North 2020, within the scope of Project Mobilizador Norte-01-0247-FEDER-024479: Valor- Natural. The GIP-USAL is financially supported by the Spanish “Ministerio de Ciencia and Innovación” (Grant PID2019-106167RB-I00) and “Junta de Castilla y León” (Grants SA093P20 and CLU-2018-04).info:eu-repo/semantics/publishedVersio

Globally-Linked Vortex Clusters in Trapped Wave Fields

We put forward the existence of a rich variety of fully stationary vortex structures, termed H-clusters, made of an increasing number of vortices nested in paraxial wave fields confined by trapping potentials. However, we show that the constituent vortices are globally linked, rather than products of independent vortices. Also, they always feature a monopolar global wave front and exist in nonlinear systems, such as Bose-Einstein condensates. Clusters with multipolar global wave fronts are non-stationary or at best flipping.Comment: 4 pages, 5 PostScript figure

La medida de la empatía en el alumnado de la Facultad de Ciencias de la Educación de Granada

El objetivo principal de este trabajo de investigación ha sido analizar la capacidad empática de 100 universitarios de la Facultad de Ciencias de la Educación de Granada. Para ello hemos utilizado el “Interpersonal Reactivity Index” (IRI), que es uno de los cuestionarios más utilizados para evaluar esta capacidad. Este instrumento incluye dos subescalas dedicadas a factores cognitivos, la toma de perspectiva (PT) y la fantasía (FS) y otras dos a factores emocionales, la preocupación empática (EC) y el malestar personal (PD).The main aim of this research was to analyse the capacity for empathy in 100 university students from the Faculty of Education in Granada. We used the “Interpersonal Reactivity Index” (IRI), which is one of the most common instruments used to evaluate this capacity. It contains two subscales to measure cognitive factors, perspective taking (PT) and Fantasy and two subscales to measures emotional factors, empathic concern (EC) and personal distress (PD).Departamento de Psicología Socia

Oscillatory Size-Dependence of the Surface Plasmon Linewidth in Metallic Nanoparticles

We study the linewidth of the surface plasmon resonance in the optical absorption spectrum of metallic nanoparticles, when the decay into electron-hole pairs is the dominant channel. Within a semiclassical approach, we find that the electron-hole density-density correlation oscillates as a function of the size of the particles, leading to oscillations of the linewidth. This result is confirmed numerically for alkali and noble metal particles. While the linewidth can increase strongly, the oscillations persist when the particles are embedded in a matrix.Comment: RevTeX4, 5 pages, 2 figures, final versio

Nonlinear Lattice Waves in Random Potentials

Localization of waves by disorder is a fundamental physical problem encompassing a diverse spectrum of theoretical, experimental and numerical studies in the context of metal-insulator transition, quantum Hall effect, light propagation in photonic crystals, and dynamics of ultra-cold atoms in optical arrays. Large intensity light can induce nonlinear response, ultracold atomic gases can be tuned into an interacting regime, which leads again to nonlinear wave equations on a mean field level. The interplay between disorder and nonlinearity, their localizing and delocalizing effects is currently an intriguing and challenging issue in the field. We will discuss recent advances in the dynamics of nonlinear lattice waves in random potentials. In the absence of nonlinear terms in the wave equations, Anderson localization is leading to a halt of wave packet spreading. Nonlinearity couples localized eigenstates and, potentially, enables spreading and destruction of Anderson localization due to nonintegrability, chaos and decoherence. The spreading process is characterized by universal subdiffusive laws due to nonlinear diffusion. We review extensive computational studies for one- and two-dimensional systems with tunable nonlinearity power. We also briefly discuss extensions to other cases where the linear wave equation features localization: Aubry-Andre localization with quasiperiodic potentials, Wannier-Stark localization with dc fields, and dynamical localization in momentum space with kicked rotors.Comment: 45 pages, 19 figure

Spectral fluctuation properties of spherical nuclei

The spectral fluctuation properties of spherical nuclei are considered by use of NNSD statistic. With employing a generalized Brody distribution included Poisson, GOE and GUE limits and also MLE technique, the chaoticity parameters are estimated for sequences prepared by all the available empirical data. The ML-based estimated values and also KLD measures propose a non regular dynamic. Also, spherical odd-mass nuclei in the mass region, exhibit a slight deviation to the GUE spectral statistics rather than the GOE.Comment: 10 pages, 2 figure