1,752 research outputs found

    Is it "natural" to expect Economics to become a part of the Natural Sciences?

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    We are in the middle of a complex debate as to whether Economics is really a proper natural science. The 'Discussion & Debate' issue of this Euro. Phys. J. Special Topic volume is: 'Can economics be a Physical Science?' I discuss some aspects here.Comment: 7 pages; EPJ-ST special issue on 'Can Economics be a Physical Science?' Edited by S. Sinha, A. S. Chakrabarti & M. Mitr

    Fat tailed distributions for deaths in conflicts and disasters

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    We study the statistics of human deaths from wars, conflicts, similar man-made conflicts as well as natural disasters. The probability distribution of number of people killed in natural disasters as well as man made situations show power law decay for the largest sizes, with similar exponent values. Comparisons with natural disasters, when event sizes are measured in terms of physical quantities (e.g., energy released in earthquake, volume of rainfall, land area affected in forest fires, etc.) also show striking resemblances. The universal patterns in their statistics suggest that some subtle similarities in their mechanisms and dynamics might be responsible.Comment: 6 pages, 3 figs + 2 table

    Competing field pulse induced dynamic transition in Ising models

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    The dynamic magnetization-reversal phenomena in the Ising model under a finite-duration external magnetic field competing with the existing order for T<Tc0T<T_c^0 has been discussed. The nature of the phase boundary has been estimated from the mean-field equation of motion. The susceptibility and relaxation time diverge at the MF phase boundary. A Monte Carlo study also shows divergence of relaxation time around the phase boundary. Fluctuation of order parameter also diverge near the phase boundary. The behavior of the fourth order cumulant shows two distinct behavior: for low temperature and pulse duration region of the phase boundary the value of the cumulant at the crossing point for different system sizes is much less than that corersponding to the static transition in the same dimension which indicate a new universality class for the dynamic transition. Also, for higher temperature and pulse duration, the transition seem to fall in a mean-field like weak-singularity universality class.Comment: 12 pages, 17 ps & eps figures, to appear in a Special Issue of Phase Transitions (2004), Ed. S. Pur

    Kinetic models for wealth exchange on directed networks

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    We propose some kinetic models of wealth exchange and investigate their behavior on directed networks though numerical simulations. We observe that network topology and directedness yields a variety of interesting features in these models. The nature of asset distribution in such directed networks show varied results, the degree of asset inequality increased with the degree of disorder in the graphs.Comment: 6 pages, 5 figs, RevTeX