Near-threshold correlations of neutrons

The appearance of charged-particle clustering in near-threshold configuration is a phenomenon that can be explained in the Open Quantum System description of the atomic nucleus. In this work we apply the realistic Shell Model Embedded in the Continuum to elucidate the emergence of neutron correlations in near-threshold many-body states coupled to l=1,2 neutron decay channels. Spectral consequences of such continuum coupling are briefly discussed together with the emergence of complex multi-neutron correlations.Comment: Invited talk at XXXIII Mazurian Lakes Conference on Physic

Granular-Scale Elementary Flux Emergence Episodes in a Solar Active Region

We analyze data from Hinode spacecraft taken over two 54-minute periods during the emergence of AR 11024. We focus on small-scale portions within the observed solar active region and discover the appearance of very distinctive small-scale and short-lived dark features in Ca II H chromospheric filtergrams and Stokes I images. The features appear in regions with close-to-zero longitudinal magnetic field, and are observed to increase in length before they eventually disappear. Energy release in the low chromospheric line is detected while the dark features are fading. In time series of magnetograms a diverging bipolar configuration is observed accompanying the appearance of the dark features and the brightenings. The observed phenomena are explained as evidencing elementary flux emergence in the solar atmosphere, i.e small-scale arch filament systems rising up from the photosphere to the lower chromosphere with a length scale of a few solar granules. Brightenings are explained as being the signatures of chromospheric heating triggered by reconnection of the rising loops (once they reached chromospheric heights) with pre-existing magnetic fields as well as to reconnection/cancellation events in U-loop segments of emerging serpentine fields. We study the temporal evolution and dynamics of the events and compare them with the emergence of magnetic loops detected in quiet sun regions and serpentine flux emergence signatures in active regions. Incorporating the novel features of granular-scale flux emergence presented in this study we advance the scenario for serpentine flux emergence.Comment: 24 pages, 9 figures. Accepted for publication in Solar Physic

The emergence of interstellar molecular complexity explained by interacting networks

Recent years have witnessed the detection of an increasing number of complex organicmolecules in interstellar space, some of them being of prebiotic interest. Disentanglingthe origin of interstellar prebiotic chemistry and its connection to biochemistry andultimately, to biology is an enormously challenging scientific goal where the applicationof complexity theory and network science has not been fully exploited. Encouragedby this idea, we present a theoretical and computational framework to model theevolution of simple networked structures toward complexity. In our environment,complex networks represent simplified chemical compounds and interact optimizing thedynamical importance of their nodes. We describe the emergence of a transition fromsimple networks toward complexity when the parameter representing the environmentreaches a critical value. Notably, although our system does not attempt to model the rulesof real chemistry nor is dependent on external input data, the results describe the emer-gence of complexity in the evolution of chemical diversity in the interstellar medium.Furthermore, they reveal an as yet unknown relationship between the abundances ofmolecules in dark clouds and the potential number of chemical reactions that yieldthem as products, supporting the ability of the conceptual framework presented here toshed light on real scenarios. Our work reinforces the notion that some of the propertiesthat condition the extremely complex journey from the chemistry in space to prebioticchemistry and finally, to life could show relatively simple and universal patterns

Quantum Valence Criticality as Origin of Unconventional Critical Phenomena

It is shown that unconventional critical phenomena commonly observed in paramagnetic metals YbRh2Si2, YbRh2(Si0.95Ge0.05)2, and beta-YbAlB4 is naturally explained by the quantum criticality of Yb-valence fluctuations. We construct the mode coupling theory taking account of local correlation effects of f electrons and find that unconventional criticality is caused by the locality of the valence fluctuation mode. We show that measured low-temperature anomalies such as divergence of uniform spin susceptibility \chi T^{-\zeta) with $\zeta~0.6$ giving rise to a huge enhancement of the Wilson ratio and the emergence of T-linear resistivity are explained in a unified way.Comment: 5 pages, 3 figures, to be published in Physical Review Letter

Random manifolds in non-linear resistor networks: Applications to varistors and superconductors

We show that current localization in polycrystalline varistors occurs on paths which are, usually, in the universality class of the directed polymer in a random medium. We also show that in ceramic superconductors, voltage localizes on a surface which maps to an Ising domain wall. The emergence of these manifolds is explained and their structure is illustrated using direct solution of non-linear resistor networks