816 research outputs found

    Zero-Temperature Complex Replica Zeros of the ±J\pm J Ising Spin Glass on Mean-Field Systems and Beyond

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    Zeros of the moment of the partition function [Zn]J[Z^n]_{\bm{J}} with respect to complex nn are investigated in the zero temperature limit β→∞\beta \to \infty, n→0n\to 0 keeping y=βn≈O(1)y=\beta n \approx O(1). We numerically investigate the zeros of the ±J\pm J Ising spin glass models on several Cayley trees and hierarchical lattices and compare those results. In both lattices, the calculations are carried out with feasible computational costs by using recursion relations originated from the structures of those lattices. The results for Cayley trees show that a sequence of the zeros approaches the real axis of yy implying that a certain type of analyticity breaking actually occurs, although it is irrelevant for any known replica symmetry breaking. The result of hierarchical lattices also shows the presence of analyticity breaking, even in the two dimensional case in which there is no finite-temperature spin-glass transition, which implies the existence of the zero-temperature phase transition in the system. A notable tendency of hierarchical lattices is that the zeros spread in a wide region of the complex yy plane in comparison with the case of Cayley trees, which may reflect the difference between the mean-field and finite-dimensional systems.Comment: 4 pages, 4 figure

    Growing Cayley trees described by Fermi distribution

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    We introduce a model for growing Cayley trees with thermal noise. The evolution of these hierarchical networks reduces to the Eden model and the Invasion Percolation model in the limit T→0T\to 0, T→∞T\to \infty respectively. We show that the distribution of the bond strengths (energies) is described by the Fermi statistics. We discuss the relation of the present results with the scale-free networks described by Bose statistics

    Analytical controllability of deterministic scale-free networks and Cayley trees

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    According to the exact controllability theory, the controllability is investigated analytically for two typical types of self-similar bipartite networks, i.e., the classic deterministic scale-free networks and Cayley trees. Due to their self-similarity, the analytical results of the exact controllability are obtained, and the minimum sets of driver nodes (drivers) are also identified by elementary transformations on adjacency matrices. For these two types of undirected networks, no matter their links are unweighted or (nonzero) weighted, the controllability of networks and the configuration of drivers remain the same, showing a robustness to the link weights. These results have implications for the control of real networked systems with self-similarity.Comment: 7 pages, 4 figures, 1 table; revised manuscript; added discussion about the general case of DSFN; added 3 reference
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