The Dynamical Systems Approach to Modeling: The Universe as a Case Study

2018 ◽  
pp. 9-18
Author(s):  
Ailier Rivero-Acosta ◽  
Adrian Linares-Rodriguez ◽  
Carlos R. Fadragas
Keyword(s):  
Dynamical Systems ◽  
Systems Approach ◽  
The Universe

A New Avenue of Research for Improving the Predictability of Weather Extremes - The Eastern Mediterranen as a Case Study

2020 ◽  
Author(s):  
Assaf Hochman ◽  
Pinhas Alpert ◽  
Hadas Saaroni ◽  
Tzvi Harpaz ◽  
Joaquim G. Pinto ◽  
...  
Keyword(s):  
Dynamical Systems ◽  
Systems Approach ◽  
Eastern Mediterranean ◽  
Extreme Weather ◽  
Extreme Weather Events ◽  
Weather Extremes ◽  
Systems Perspective ◽  
Weather Events ◽  
The Mediterranean

<p>Extreme weather events have long been considered challenging to predict. It is likely that global warming will trigger extreme weather in many regions of the globe and especially over the Mediterranean ´hot spot´. Therefore, extreme weather events have been selected as one of the grand challenges of the World Climate Research Program.</p><p>The intrinsic predictability of a weather system, or any dynamical system, depends on its persistence and its active number of degrees of freedom. Recent developments in dynamical systems theory allow to compute these metrics for atmospheric configurations (1). In most of the mid-latitudes, synoptic scale patterns exert a strong control on regional weather, thus, stimulating a broad interest, especially in weather forecasting. Recently, we have integrated the dynamical systems approach with a synoptic classification algorithm over the Eastern Mediterranean (2).  It was shown that the dynamical systems perspective provides an extremely informative tool for evaluating the predictability of synoptic patterns and especially of weather extremes.</p><p>The novel perspective, which leverages a dynamical systems approach to investigate the predictability of extreme weather events, outlines a new avenue of research that may be fruitfully applied at operational weather and climate forecasting services in the Mediterranean Region and around the globe.</p><p><strong>References</strong></p><ol><li>Faranda D, Messori G, Yiou P. 2017. Dynamical Proxies of North Atlantic Predictability and Extremes. Scientific Reports <strong>7</strong>, 412782017b. DOI: 10.1038/srep4127</li> <li>Hochman A, Alpert P, Harpaz T, Saaroni H, Messori G. 2019. A New Dynamical Systems Perspective on Atmospheric Predictability; Eastern Mediterranean Weather Regimes as a Case Study. Science Advances <strong>5</strong>. DOI: 10.1126/sciadv.aau0936</li> </ol>

Universe with wet dark fluid: A dynamical systems approach

2019 ◽  
Vol 16 (08) ◽  
pp. 1950127 ◽  
Author(s):  
S. Angit ◽  
Rakesh Raushan ◽  
R. Chaubey
Keyword(s):  
Dynamical Systems ◽  
Equation Of State ◽  
Cosmological Model ◽  
Evolution Equations ◽  
Systems Approach ◽  
Wet Dark Fluid ◽  
Dark Fluid ◽  
State Formula ◽  
Frw Cosmological Model ◽  
The Universe

We investigate the dynamical systems analysis of Friedmann–Robertson–Walker (FRW) cosmological model with wet dark fluid. A new equation of state for the dark energy component of the Universe has been used. It is modeled by the equation of state [Formula: see text], which can describe a liquid, e.g. water. To analyze the evolution equations, we have introduced suitable transformation of variables. The evolution of corresponding solutions is presented by curves in the phase–plane diagram. The nature of critical points are analyzed and stable attractors are examined for our cosmological model. We determine the classical stabilities of these cosmologies. We also examine the transition of early decelerating stage of the Universe to present the accelerating stage of the Universe.

Turning Aliens into Socialists

2010 ◽  
Vol 1 (1) ◽  
pp. 75-93
Author(s):  
Jessica Moberg
Keyword(s):  
Outer Space ◽  
The United States ◽  
Second World War ◽  
World War ◽  
History Of ◽  
Swedish History ◽  
Second World ◽  
The Universe ◽  
Highly Evolved

Immediately after the Second World War Sweden was struck by a wave of sightings of strange flying objects. In some cases these mass sightings resulted in panic, particularly after authorities failed to identify them. Decades later, these phenomena were interpreted by two members of the Swedish UFO movement, Erland Sandqvist and Gösta Rehn, as alien spaceships, or UFOs. Rehn argued that ‘[t]here is nothing so dramatic in the Swedish history of UFOs as this invasion of alien fly-things’ (Rehn 1969: 50). In this article the interpretation of such sightings proposed by these authors, namely that we are visited by extraterrestrials from outer space, is approached from the perspective of myth theory. According to this mythical theme, not only are we are not alone in the universe, but also the history of humankind has been shaped by encounters with more highly-evolved alien beings. In their modern day form, these kinds of ideas about aliens and UFOs originated in the United States. The reasoning of Sandqvist and Rehn exemplifies the localization process that took place as members of the Swedish UFO movement began to produce their own narratives about aliens and UFOs. The question I will address is: in what ways do these stories change in new contexts? Texts produced by the Swedish UFO movement are analyzed as a case study of this process.

scholarly journals Nucleation is more than critical: A case study of the electroweak phase transition in the NMSSM

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Sebastian Baum ◽  
Marcela Carena ◽  
Nausheen R. Shah ◽  
Carlos E. M. Wagner ◽  
Yikun Wang
Keyword(s):  
Phase Transition ◽  
Parameter Space ◽  
Local Minima ◽  
Critical Temperatures ◽  
Electroweak Phase Transition ◽  
First Order ◽  
Vacuum Structure ◽  
The Universe ◽  
Scalar Sector

Abstract Electroweak baryogenesis is an attractive mechanism to generate the baryon asymmetry of the Universe via a strong first order electroweak phase transition. We compare the phase transition patterns suggested by the vacuum structure at the critical temperatures, at which local minima are degenerate, with those obtained from computing the probability for nucleation via tunneling through the barrier separating local minima. Heuristically, nucleation becomes difficult if the barrier between the local minima is too high, or if the distance (in field space) between the minima is too large. As an example of a model exhibiting such behavior, we study the Next-to-Minimal Supersymmetric Standard Model, whose scalar sector contains two SU(2) doublets and one gauge singlet. We find that the calculation of the nucleation probabilities prefers different regions of parameter space for a strong first order electroweak phase transition than the calculation based solely on the critical temperatures. Our results demonstrate that analyzing only the vacuum structure via the critical temperatures can provide a misleading picture of the phase transition patterns, and, in turn, of the parameter space suitable for electroweak baryogenesis.

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