1,566 research outputs found
Is it "natural" to expect Economics to become a part of the Natural Sciences?
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
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
The dynamic magnetization-reversal phenomena in the Ising model under a
finite-duration external magnetic field competing with the existing order for
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
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
The Origin of Helicity in Solar Active Regions
We present calculations of helicity based on our solar dynamo model and show
that the results are consistent with observational data.Comment: To appear in the Proceedings of IAU Symposium 22
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