815 research outputs found
What makes slow samples slow in the Sherrington-Kirkpatrick model
Using results of a Monte Carlo simulation of the Sherrington-Kirkpatrick
model, we try to characterize the slow disorder samples, namely we analyze
visually the correlation between the relaxation time for a given disorder
sample with several observables of the system for the same disorder sample.
For temperatures below but not too low, fast samples (small relaxation
times) are clearly correlated with a small value of the largest eigenvalue of
the coupling matrix, a large value of the site averaged local field probability
distribution at the origin, or a small value of the squared overlap is more robust) . There is a strong correlation between the values of
the relaxation time for two distinct values of the temperature, but this
correlation decreases as the system size is increased. This may indicate the
onset of temperature chaos
The role of hidden influentials in the diffusion of online information cascades
In a diversified context with multiple social networking sites, heterogeneous
activity patterns and different user-user relations, the concept of
"information cascade" is all but univocal. Despite the fact that such
information cascades can be defined in different ways, it is important to check
whether some of the observed patterns are common to diverse contagion processes
that take place on modern social media. Here, we explore one type of
information cascades, namely, those that are time-constrained, related to two
kinds of socially-rooted topics on Twitter. Specifically, we show that in both
cases cascades sizes distribute following a fat tailed distribution and that
whether or not a cascade reaches system-wide proportions is mainly given by the
presence of so-called hidden influentials. These latter nodes are not the hubs,
which on the contrary, often act as firewalls for information spreading. Our
results are important for a better understanding of the dynamics of complex
contagion and, from a practical side, for the identification of efficient
spreaders in viral phenomena.Comment: Submitted to EPJ Data Scienc
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