Yiannis Contoyiannis
University of the West
Particle physicsMagnetic fieldQuantum chromodynamicsPhysicsStatistical physicsCriticalitySpontaneous symmetry breakingGeologyCritical point (thermodynamics)Phase transitionCritical exponentSeismologyField (physics)Critical phenomenaSymmetry breakingCondensed matter physicsIntermittencyMathematicsFracture (geology)Ising modelRenormalization groupGeophysicsPower law
68Publications
19H-index
706Citations
Publications 64
Newest
We investigate the possibility to observe the QCD critical point in A+A collisions at the SPS. Guided by the QCD phase diagram expressed in experimentally accessible variables we suggest that the process C+C at 158 GeV/n freezes out very close to the critical point. We perform an analysis of the available preliminary experimental data for a variety of SPS processes. The basic tool in our efforts is the reconstruction of the critical isoscalar sector which is formed at the critical point. Our res...
#1Yiannis Contoyiannis (UoA: National and Kapodistrian University of Athens)H-Index: 19
#2Fotis K. DiakonosH-Index: 26
Last. George TheophilidisH-Index: 21
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: We investigate the spontaneous contraction generated by the atria of a frog's heart isolated in a physiological solution. In the relaxation phase, the recorded time series for two different sampling rates possesses an intermittent component similar to the dynamics of the order parameter's fluctuations of a thermal critical system belonging to the mean field universality class. This behavior is not visible through conventional analysis in the frequency space due to the presence of Brownian nois...
18 CitationsSource
#1Yiannis Contoyiannis (UoA: National and Kapodistrian University of Athens)H-Index: 19
#2Fotis K. Diakonos (UoA: National and Kapodistrian University of Athens)H-Index: 26
Last. Konstantinos Eftaxias (UoA: National and Kapodistrian University of Athens)H-Index: 29
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Abstract It has been proposed that large earthquakes (EQ) are similar to critical phenomena. A new method for the research of the critical fluctuations and for the estimation of corresponding critical exponents is applied to the very high frequency (VHF) electromagnetic (EM) time-series recorder prior to the Kozani–Grevena (K–G) earthquake (EQ) in Greece ( M s =6.6, on May 13, 1995). Such ruptures involve interactions between structures at many different scales. The system investigated might be ...
21 CitationsSource
A detailed study of correlated scalars, produced in collisions of nuclei and associated with the \sigmafield fluctuations, (\delta \sigma)^2= at the QCD critical point (critical fluctuations), is performed on the basis of a critical event generator (Critical Monte-Carlo) developed in our previous work. The aim of this analysis is to reveal suitable observables of critical QCD in the multiparticle environment of simulated events and select appropriate signatures of the critical point, asso...
#1Yiannis Contoyiannis (UoA: National and Kapodistrian University of Athens)H-Index: 19
#2Fotis K. DiakonosH-Index: 26
Last. Malakis AH-Index: 1
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We argue that the fluctuations of the order parameter in a complex system at the critical point can be described in terms of intermittent dynamics of type I. Based on this observation we develop an algorithm to calculate the isothermal critical exponent δ for a "thermal" critical system. We apply successfully our approach to the 3D Ising model. The intermittent character of these "critical" dynamics guides to the introduction of a new exponent which extends the notion of the exponent δ to nonthe...
89 CitationsSource
#2Fotis K. DiakonosH-Index: 26
Last. Konstantinos EftaxiasH-Index: 29
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#1N. G. Antoniou (UoA: National and Kapodistrian University of Athens)H-Index: 5
#2Yiannis Contoyiannis (UoA: National and Kapodistrian University of Athens)H-Index: 19
Last. C. N. Ktorides (UoA: National and Kapodistrian University of Athens)H-Index: 9
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Abstract A theoretical scheme which relates multiparticle states generated in ultrarelativistic nuclear collisions to a QCD phase transition is considered in the framework of the universality class provided by the 3D Ising model. Two different evolution scenarios for the QGP system are examined. The statistical mechanics of the critical state is accounted for in terms of (critical) cluster formation consistent with suitably cast effective action functionals, one for each considered type of expan...
73 CitationsSource
#1N. G. Antoniou (UoA: National and Kapodistrian University of Athens)H-Index: 1
#2Yiannis Contoyiannis (UoA: National and Kapodistrian University of Athens)H-Index: 19
Last. Fotis K. Diakonos (UoA: National and Kapodistrian University of Athens)H-Index: 26
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We investigate the geometry of a critical system undergoing a second-order thermal phase transition. Using a local description for the dynamics characterizing the system at the critical point {T=T}_{c},we reveal the formation of clusters with fractal geometry, where the term cluster is used to describe regions with a nonvanishing value of the order parameter. We show that, treating the cluster as an open subsystem of the entire system, new instanton-like configurations dominate the statistica...
20 CitationsSource
#1Yiannis Contoyiannis (UoA: National and Kapodistrian University of Athens)H-Index: 19
#2Fotis K. Diakonos (UoA: National and Kapodistrian University of Athens)H-Index: 26
Abstract We consider a critical system at equilibrium in terms of a characteristic extensive quantity M = M ( φ ) where φ is the corresponding order parameter. The random averaging over the configurations contributing to the critical partition function is replaced by a deterministic dynamical averaging along trajectories of a suitable defined map. At the critical point this map shows a remarkable consistency in describing characteristic properties of the system, like the fractal geometry of the ...
86 CitationsSource
#1N. G. Antoniou (UoA: National and Kapodistrian University of Athens)H-Index: 18
#2Yiannis Contoyiannis (UoA: National and Kapodistrian University of Athens)H-Index: 19
Last. Fotis K. Diakonos (UoA: National and Kapodistrian University of Athens)H-Index: 26
view all 3 authors...
Abstract A critical point of second order, belonging to the universality class of 3 d Ising model, has been recently advocated as a strong candidate for the critical behaviour of QCD with non-zero quark masses. The implications of this conjecture are investigated, in the multi-particle environment of relativistic heavy ion collisions. A universal intermittency pattern of pion density fluctuations in momentum space is found reflecting the fractal structure of the critical system in configuration ...
2 CitationsSource