843 research outputs found
The mechanism of double exponential growth in hyper-inflation
Analyzing historical data of price indices we find an extraordinary growth
phenomenon in several examples of hyper-inflation in which price changes are
approximated nicely by double-exponential functions of time. In order to
explain such behavior we introduce the general coarse-graining technique in
physics, the Monte Carlo renormalization group method, to the price dynamics.
Starting from a microscopic stochastic equation describing dealers' actions in
open markets we obtain a macroscopic noiseless equation of price consistent
with the observation. The effect of auto-catalytic shortening of characteristic
time caused by mob psychology is shown to be responsible for the
double-exponential behavior.Comment: 9 pages, 5 figures and 2 tables, submitted to Physica
The Grounds For Time Dependent Market Potentials From Dealers' Dynamics
We apply the potential force estimation method to artificial time series of
market price produced by a deterministic dealer model. We find that dealers'
feedback of linear prediction of market price based on the latest mean price
changes plays the central role in the market's potential force. When markets
are dominated by dealers with positive feedback the resulting potential force
is repulsive, while the effect of negative feedback enhances the attractive
potential force.Comment: 9 pages, 3 figures, proceedings of APFA
Neutrino texture saturating the CP asymmetry
We study a neutrino mass texture which can explain the neutrino oscillation
data and also saturate the upper bound of the CP asymmetry in the
leptogenesis. We consider the thermal and non-thermal leptogenesis based on the
right-handed neutrino decay in this model. A lower bound of the reheating
temperature required for the explanation of the baryon number asymmetry is
estimated as GeV for the thermal leptogenesis and GeV for
the non-thermal one.It can be lower than the upper bound of the reheating
temperature imposed by the cosmological gravitino problem. An example of the
construction of the discussed texture is also presented.Comment: 23 pages, 6 figure
Effect of spatial bias on the nonequilibrium phase transition in a system of coagulating and fragmenting particles
We examine the effect of spatial bias on a nonequilibrium system in which
masses on a lattice evolve through the elementary moves of diffusion,
coagulation and fragmentation. When there is no preferred directionality in the
motion of the masses, the model is known to exhibit a nonequilibrium phase
transition between two different types of steady states, in all dimensions. We
show analytically that introducing a preferred direction in the motion of the
masses inhibits the occurrence of the phase transition in one dimension, in the
thermodynamic limit. A finite size system, however, continues to show a
signature of the original transition, and we characterize the finite size
scaling implications of this. Our analysis is supported by numerical
simulations. In two dimensions, bias is shown to be irrelevant.Comment: 7 pages, 7 figures, revte
Exact Phase Diagram of a model with Aggregation and Chipping
We revisit a simple lattice model of aggregation in which masses diffuse and
coalesce upon contact with rate 1 and every nonzero mass chips off a single
unit of mass to a randomly chosen neighbour with rate . The dynamics
conserves the average mass density and in the stationary state the
system undergoes a nonequilibrium phase transition in the plane
across a critical line . In this paper, we show analytically that in
arbitrary spatial dimensions, exactly and hence,
remarkably, independent of dimension. We also provide direct and indirect
numerical evidence that strongly suggest that the mean field asymptotic answer
for the single site mass distribution function and the associated critical
exponents are super-universal, i.e., independent of dimension.Comment: 11 pages, RevTex, 3 figure
Propagation and Extinction in Branching Annihilating Random Walks
We investigate the temporal evolution and spatial propagation of branching
annihilating random walks in one dimension. Depending on the branching and
annihilation rates, a few-particle initial state can evolve to a propagating
finite density wave, or extinction may occur, in which the number of particles
vanishes in the long-time limit. The number parity conserving case where
2-offspring are produced in each branching event can be solved exactly for unit
reaction probability, from which qualitative features of the transition between
propagation and extinction, as well as intriguing parity-specific effects are
elucidated. An approximate analysis is developed to treat this transition for
general BAW processes. A scaling description suggests that the critical
exponents which describe the vanishing of the particle density at the
transition are unrelated to those of conventional models, such as Reggeon Field
Theory. P. A. C. S. Numbers: 02.50.+s, 05.40.+j, 82.20.-wComment: 12 pages, plain Te
Long-term power-law fluctuation in Internet traffic
Power-law fluctuation in observed Internet packet flow are discussed. The
data is obtained by a multi router traffic grapher (MRTG) system for 9 months.
The internet packet flow is analyzed using the detrended fluctuation analysis.
By extracting the average daily trend, the data shows clear power-law
fluctuations. The exponents of the fluctuation for the incoming and outgoing
flow are almost unity. Internet traffic can be understood as a daily periodic
flow with power-law fluctuations.Comment: 10 pages, 8 figure
Dynamical Phase Transition in One Dimensional Traffic Flow Model with Blockage
Effects of a bottleneck in a linear trafficway is investigated using a simple
cellular automaton model. Introducing a blockage site which transmit cars at
some transmission probability into the rule-184 cellular automaton, we observe
three different phases with increasing car concentration: Besides the free
phase and the jam phase, which exist already in the pure rule-184 model, the
mixed phase of these two appears at intermediate concentration with
well-defined phase boundaries. This mixed phase, where cars pile up behind the
blockage to form a jam region, is characterized by a constant flow. In the
thermodynamic limit, we obtain the exact expressions for several characteristic
quantities in terms of the car density and the transmission rate. These
quantities depend strongly on the system size at the phase boundaries; We
analyse these finite size effects based on the finite-size scaling.Comment: 14 pages, LaTeX 13 postscript figures available upon
request,OUCMT-94-
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