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Y. F. Contoyiannis
National and Kapodistrian University of Athens
PhysicsCritical point (thermodynamics)Phase transitionSeismologyCritical phenomena
41Publications
15H-index
523Citations
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Publications 58
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#1Y. F. ContoyiannisH-Index: 15
Last. S.G. Stavrinides (International Hellenic University)H-Index: 1
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We investigate about the existence of static solitons solutions in the inverse G-L free energy in phase transitions of {\phi}4 theory. We calculate all the characteristics of these solitons , like localized structure, finite energy and mass . We show that solitons appears in spontaneous symmetry breaking (SSB) phenomenon only if the critical point is in excited state. When the time is introduced we shown that the static solitons of SSB remain as solitons in Minkowski space-time while the static ...
#1Y. F. ContoyiannisH-Index: 15
#2S.G. StavrinidesH-Index: 1
Last. S.M. PotirakisH-Index: 1
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The scope of this work is to serve as a guiding tool against subjective estimations on real pandemic situations (mainly due to the inability to acquire objective real data over whole populations). The previously introduced model of closed self-organized criticality (SOC), is adapted in the case of a virus-induced epidemic. In this version this physical model can distinguish the virus spread according to the virus aggressiveness. The study presented, highlights the critical value of virus density...
#1Y. F. ContoyiannisH-Index: 15
Last. F K DiakonosH-Index: 21
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The detection of power laws in real data is a demanding task for several reasons. The two most frequently met are that (i) real data possess noise, which affects the power-law tails significantly, and (ii) there is no solid tool for discrimination between a power law, valid in a specific range of scales, and other functional forms like log-normal or stretched exponential distributions. In the present report we demonstrate, employing simulated and real data, that using wavelets it is possible to ...
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#1Yiannis Contoyiannis (UWest: University of the West)H-Index: 3
#1Y. F. Contoyiannis (UWest: University of the West)H-Index: 15
Last. F K Diakonos (UoA: National and Kapodistrian University of Athens)H-Index: 21
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Abstract We show that, in continuous phase transitions, the order parameter fluctuations in time, are characterized by a resonant phenomenon, occurring whenever a physical system enters in a critical region. It is realized in the mean waiting time 〈 λ 〉 of the order parameter time-series, in the immediate neighbourhood of its equilibrium (mean) value. By varying the control parameter within the critical region, 〈 λ 〉 becomes maximum at the critical point. To illustrate this resonant behaviour, w...
Source
#1Y. F. ContoyiannisH-Index: 15
#2S.G. StavrinidesH-Index: 1
Last. S.M. PotirakisH-Index: 1
view all 6 authors...
The previously introduced model of self-organized criticality, is adapted in the case of a virus-induced epidemic. The study presented in the following lines, highlights the critical value of virus density over a population. For low values of the initial virus density (lower than the critical value) it is proved that the virus-diffusion behavior safe and it is quantitatively similar to usual real epidemical data. The study reveals that very close to the critical point, the critical slowing-down ...
#2Y. F. ContoyiannisH-Index: 15
Last. Constantinos NomicosH-Index: 18
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In this brief report we present evidence for the dynamics of the earthquake (EQ) preparation processes that led to two strong events (Mw>6) that took place in Durres (Albania) and Chania (West-Crete, Greece) on 26 and 27-11-2019, respectively. Specifically, MHz fracto-electromagnetic emissions (EME) recorded by our telemetric stations presented critical fluctuations prior to each one of these EQs. Subsequently, the EME possibly related to each one of these EQs evolved differently towards the occ...
In this work we apply the Method of Critical Fluctuations (MCF)on human Electrocardiogram (ECG) time-series. The method is able to reveal critical characteristics, in terms of physical behavior, in experimentally recorded signals. Using the concept of criticality as basic criterion for the characterization of the recorded ECG as that of a healthy person, we find a 100% verification of the characterization Myocardial infarction. In contrary in the cases of the characterization Healthy control we ...
#1Stelios M. Potirakis (UWest: University of the West)H-Index: 3
#2Yiannis Contoyiannis (UWest: University of the West)H-Index: 3
Last. Konstantinos Eftaxias (UoA: National and Kapodistrian University of Athens)H-Index: 28
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Abstract In course of the preparation of a strong earthquake (EQ), the fracture of the highly heterogeneous system surrounding the fault has been suggested to follow the theory of critical phenomena and continuous phase transitions. Among the variety of electromagnetic phenomena which have been reported to be observed prior to a strong EQ, the ground-observed fracture-induced electromagnetic emissions (EME) in the MHz band have repeatedly been reported to present intermittency-induced criticalit...
1 CitationsSource
#1Y. Contoyiannis (UWest: University of the West)H-Index: 1
#2S.M. Potirakis (UWest: University of the West)H-Index: 1
Last. Christoforos G. Theodorou (LAHC: Los Angeles Harbor College)H-Index: 8
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Abstract The drain current in nanoscale fully depleted ultra-thin body and buried oxide n-MOSFETs is studied in terms of critical dynamics. The time series formed by the measured current through the channel of the MOSFET, appears to have the form of random telegraph noise (RTN). This timeseries is analyzed by the Method of Critical Fluctuation (MCF). Its dynamics are compatible with critical intermittency. According to the quantitative analysis performed, the current-value distributions are comp...
1 CitationsSource
In this work we reveal that the inside-outside dynamic model for the production of fermion-antifermion pair (or quark-antiquark in QCD), is an out of equilibrium process. Properties of a complex system as the self-similarity and the critical point of a continuous phase transition in equilibrium appear. In this work we show that this is accomplished imposing a type of mapping process through a self-composition operator on a QED_2 bosons (or pions) field.
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