Maximum entropy approach to power-law distributions in coupled dynamic-stochastic systems

Statistical properties of coupled dynamic-stochastic systems are studied within a combination of the maximum information principle and the superstatistical approach. The conditions at which the Shannon entropy functional leads to a power-law statistics are investigated. It is demonstrated that, from a quite general point of view, the power-law dependencies may appear as a consequence of "global" constraints restricting both the dynamic phase space and the stochastic fluctuations. As a result, at sufficiently long observation times the dynamic counterpart is driven into a non-equilibrium steady state whose deviation from the usual exponential statistics is given by the distance from the conventional equilibrium

EAGLE ISS - A modular twin-channel integral-field near-IR spectrograph

The ISS (Integral-field Spectrograph System) has been designed as part of the EAGLE Phase A Instrument Study for the E-ELT. It consists of two input channels of 1.65x1.65 arcsec field-of-view, each reconfigured spatially by an image-slicing integral-field unit to feed a single near-IR spectrograph using cryogenic volume-phase-holographic (VPH) gratings to disperse the image spectrally. A 4k x 4k array detector array records the dispersed images. The optical design employs anamorphic magnification, image slicing, VPH gratings scanned with a novel cryo-mechanism and a three-lens camera. The mechanical implementation features IFU optics in Zerodur, a modular bench structure and a number of high-precision cryo-mechanisms.Comment: 12 pages, to be published in Proc SPIE 7735: Ground-based & Airborne Instrumentation for Astronomy II

Hysteresis and Avalanches in the Random Anisotropy Ising Model

The behaviour of the Random Anisotropy Ising model at T=0 under local relaxation dynamics is studied. The model includes a dominant ferromagnetic interaction and assumes an infinite anisotropy at each site along local anisotropy axes which are randomly aligned. Two different random distributions of anisotropy axes have been studied. Both are characterized by a parameter that allows control of the degree of disorder in the system. By using numerical simulations we analyze the hysteresis loop properties and characterize the statistical distribution of avalanches occuring during the metastable evolution of the system driven by an external field. A disorder-induced critical point is found in which the hysteresis loop changes from displaying a typical ferromagnetic magnetization jump to a rather smooth loop exhibiting only tiny avalanches. The critical point is characterized by a set of critical exponents, which are consistent with the universal values proposed from the study of other simpler models.Comment: 40 pages, 21 figures, Accepted for publication in Phys. Rev.

Temperature contour maps at the strain-induced martensitic transition of a Cu–Zn–Al shape-memory single crystal

We study temperature changes at the reverse strain-induced martensitic transformation in a Cu–Zn–Al single crystal. Infrared thermal imaging reveals a markedly inhomogeneous temperature distribution. The evolution of the contour temperature maps enables information to be extracted on the kinetics of the interface motion

Magnetic hysteresis in the Cu-Al-Mn intermetallic alloy: experiments and modeling

We study isothermal magnetization processes in the Cu-Al-Mn intermetallic alloy. Hysteresis is observed at temperatures below the spin-freezing of the system. The characteristics of the hysteresis cycles as a function of temperature and Mn content (magnetic element) are obtained. At low temperature (5 K) a change from smooth to sharp cycles is observed with increasing Mn content, which is related to the decrease of configurational disorder. We also study a zero-temperature site-diluted Ising model, suitable for the description of this Cu-Al-Mn system. The model reproduces the main features of the hysteresis loops observed experimentally. It exhibits a disorder-induced critical line separating a disordered phase from an incipient ferromagnetic ground-state. The comparison between the model and the experiments allows to conclude that the observed change in the experimental hysteresis loops can be understood within the framework of the theory of disorder-induced criticality in fluctuationless first-order phase transitions.Comment: 30 pages, 15 eps figures, 2 tables. To appear Phys. Rev. B 59 (June 1999

Prospects for discovering supersymmetric long-lived particles with MoEDAL

We present a study on the possibility of searching for long-lived supersymmetric partners with the MoEDAL experiment at the LHC. MoEDAL is sensitive to highly ionising objects such as magnetic monopoles or massive (meta)stable electrically charged particles. We focus on prospects of directly detecting long-lived sleptons in a phenomenologically realistic model which involves an intermediate neutral long-lived particle in the decay chain. This scenario is not yet excluded by the current data from ATLAS or CMS, and is compatible with astrophysical constraints. Using Monte Carlo simulation, we compare the sensitivities of MoEDAL versus ATLAS in scenarios where MoEDAL could provide discovery reach complementary to ATLAS and CMS, thanks to looser selection criteria combined with the virtual absence of background. It is also interesting to point out that, in such scenarios, in which charged staus are the main long-lived candidates, the relevant mass range for MoEDAL is compatible with a potential role of Supersymmetry in providing an explanation for the anomalous events observed by the ANITA detector.Comment: 12 pages, 6 figures; preliminary results presented in arXiv:1903.11022; matches published version in EPJ

Universal Power Law in the Noise from a Crumpled Elastic Sheet

Using high-resolution digital recordings, we study the crackling sound emitted from crumpled sheets of mylar as they are strained. These sheets possess many of the qualitative features of traditional disordered systems including frustration and discrete memory. The sound can be resolved into discrete clicks, emitted during rapid changes in the rough conformation of the sheet. Observed click energies range over six orders of magnitude. The measured energy autocorrelation function for the sound is consistent with a stretched exponential C(t) ~ exp(-(t/T)^{b}) with b = .35. The probability distribution of click energies has a power law regime p(E) ~ E^{-a} where a = 1. We find the same power law for a variety of sheet sizes and materials, suggesting that this p(E) is universal.Comment: 5 pages (revtex), 10 uuencoded postscript figures appended, html version at http://rainbow.uchicago.edu/~krame

Magnetic hysteresis in the Cu-Al-Mn intermetallic alloy: experiments and modeling

We study isothermal magnetization processes in the Cu-Al-Mn intermetallic alloy. Hysteresis is observed at temperatures below the spin-freezing of the system. The characteristics of the hysteresis cycles as a function of temperature and Mn content (magnetic element) are obtained. At low temperature (5 K) a change from smooth to sharp cycles is observed with increasing Mn content, which is related to the decrease of configurational disorder. We also study a zero-temperature site-diluted Ising model, suitable for the description of this Cu-Al-Mn system. The model reproduces the main features of the hysteresis loops observed experimentally. It exhibits a disorder-induced critical line separating a disordered phase from an incipient ferromagnetic ground-state. The comparison between the model and the experiments allows to conclude that the observed change in the experimental hysteresis loops can be understood within the framework of the theory of disorder-induced criticality in fluctuationless first-order phase transitions.Comment: 30 pages, 15 eps figures, 2 tables. To appear Phys. Rev. B 59 (June 1999

\u3ci\u3eCase Studies in Sustainability Management - The Oikos Collection Vol. 3\u3c/i\u3e

Editor: Jordi Vives Gabriel Chapter 9, Lululemon’s commitment to the environment: A tangle of seaweed, suppliers & social responsibility, co-authored by A. Erin Bass, UNO faculty member. With the rapidly growing importance of sustainability and corporate responsibility in a globalised world, management schools are increasingly integrating long-term economic, environmental and social issues into their teaching and research. Climate change, poverty, labour standards and human rights are among the many topics that future decision-makers will need to face in their careers. Business education needs to reflect this new reality and provide a broadened understanding of value creation in order to create economic capital while developing social and preserving natural capital. Case studies can be important tools for creating learning processes on different levels - students are forced to struggle with exactly the kinds of decisions and dilemmas managers confront every day. In this reflection of reality, the values and goals of the student are systematically challenged. This can be especially valuable in the context of sustainability management - organisations are now continually forced to value the different aspects of sustainability and their interrelations: How do social issues impact the economic bottom line? How can an environmentally sound strategy create a positive impact on employee motivation and thus have measurable impact on economic performance? What comes first and why? This third collection of oikos case studies is based on the winning cases from the 2010 to 2013 annual case competition. So what makes an excellent case in sustainability management? These cases have been highly praised because they provide excellent learning opportunities, tell engaging stories, deal with recent situations, include quotations from key actors, are thought-provoking and controversial, require decision-making, provide clear take-aways and are all supported by teaching guidance and comprehensive teaching notes available to faculty. These cases are clustered in three different sections: Large Corporations and Corporate Sustainability Dilemmas , Managing Stakeholder Relations and Sustainability as a Source of Differentiation Strategies . Case Studies in Sustainability Management will be an essential purchase for educators and is likely to be a widely used as a course textbook at all levels of management education.https://digitalcommons.unomaha.edu/facultybooks/1281/thumbnail.jp

Rayleigh loops in the random-field Ising model on the Bethe lattice

We analyze the demagnetization properties of the random-field Ising model on the Bethe lattice focusing on the beahvior near the disorder induced phase transition. We derive an exact recursion relation for the magnetization and integrate it numerically. Our analysis shows that demagnetization is possible only in the continous high disorder phase, where at low field the loops are described by the Rayleigh law. In the low disorder phase, the saturation loop displays a discontinuity which is reflected by a non vanishing magnetization m_\infty after a series of nested loops. In this case, at low fields the loops are not symmetric and the Rayleigh law does not hold.Comment: 8pages, 6 figure