887 research outputs found
Application of Statistical Physics to Politics
The concept and technics of real space renormalization group are applied to
study majority rule voting in hierarchical structures. It is found that
democratic voting can lead to totalitarianism by keeping in power a small
minority. Conditions of this paradox are analyzed and singled out. Indeed
majority rule produces critical thresholds to absolute power. Values of these
thresholds can vary from 50% up to at least 77%. The associated underlying
mechanism could provide an explanation for both former apparent eternity of
communist leaderships as well as their sudden collapse.Comment: Proceedings of the NATO Advanced Research Workshop, Budapest (May
1999) Eds: A. Gadomski et a
Global Physics: From Percolation to Terrorism, Guerilla Warfare and Clandestine Activities
The September 11 attack on the US has revealed an unprecedented terrorism
with worldwide range of destruction. It is argued to result from the first
worldwide percolation of passive supporters. They are people sympathetic to the
terrorism cause but without being involved with it. They just don't oppose it
in case they could. This scheme puts suppression of the percolation as the
major strategic issue in the fight against terrorism. Acting on the population
is shown to be useless. Instead a new strategic scheme is suggested to increase
the terrorism percolation threshold and in turn suppress the percolation. The
relevant associated space is identified as a multi-dimensional social space
including both the ground earth surface and all various independent flags
displayed by the terrorist group. Some hints are given on how to shrink the
geographical spreading of terrorism threat. The model apply to a large spectrum
of clandestine activities including guerilla warfare as well as tax evasion,
corruption, illegal gambling, illegal prostitution and black markets.Comment: 17 pages, 7 figures, Proceedings of the International Workshop
Randomness And Complexity in honor of Shlomo Havlin's 60th birthday held in
January 2003, Eilat, Israe
Fragmentation versus Stability in Bimodal Coalitions
Competing bimodal coalitions among a group of actors are discussed. First, a
model from political sciences is revisited. Most of the model statements are
found not to be contained in the model. Second, a new coalition model is built.
It accounts for local versus global alignment with respect to the joining of a
coalition. The existence of two competing world coaltions is found to yield one
unique stable distribution of actors. On the opposite a unique world leadership
allows the emergence of unstable relationships. In parallel to regular actors
which have a clear coalition choice, ``neutral" ``frustrated" and ``risky"
actors are produced. The cold war organisation after world war II is shown to
be rather stable. The emergence of a fragmentation process from eastern group
disappearance is explained as well as continuing western group stability. Some
hints are obtained about possible policies to stabilize world nation
relationships. European construction is analyzed with respect to european
stability. Chinese stability is also discussed.Comment: 14 pages, latex, no figures, to appear in Physica
Contrarian Deterministic Effect: the "Hung Elections Scenario"
A contrarian is someone who deliberately decides to oppoe the prevailing
choice of others. The Galam model of two state opinion dynamicsincorporates
agent updates by a single step random grouping in which all participants adopt
the opinion of their respective local majority group. The process is repeated
until a stable collective state is reached; the associated dynamics is fast.
Here we show that the introduction of contrarians may give rise to interesting
dynamics generated phases and even to a critical behavior at a contrarian
concentration . For an ordered phase is generated with a clear cut
majority-minority splitting. By contrast when the resulting disordered
phase has no majority: agents keep shifting opinions but no symmetry breaking
(i.e., the appearance of a majority) takes place. Our results are employed to
explain the outcome of the 2000 American presidential elections and that of the
2002 German parliamentary elections. Those events are found to be inevitable.
On this basis the ``hung elections scenario'' is predicted to become a common
occurrence in modern democracies.Comment: 4 pages, 3 figure
Fashion, Novelty and Optimality: An application from Physics
We apply a physical based model to describe the clothes fashion market. Every
time a new outlet appears on the market, it can invade the market under certain
specific conditions. Hence, the "old'' outlet can be completely dominated and
disappears. Each creator competes for a finite population of agents. Fashion
phenomena are shown to result from a collective phenomenon produced by local
individual imitation effects. We assume that, in each step of the imitation
process, agents only interact with a subset rather than with the whole set of
agents. People are actually more likely to influence (and be influenced by)
their close ''neighbours''. Accordingly we discuss which strategy is best
fitted for new producers when people are either simply organised into anonymous
reference groups or when they are organised in social groups hierarchically
ordered. While counterfeits are shown to reinforce the first strategy, creating
social leaders can permit to avoid them.Comment: 24 pages, 7 figure
A geometrical model for Mixed cyanide crystals
A model of diluted random field sustained by quenched volume deformations is
shown to reproduce puzzling physical features found in X(CN)_{x}Y_{1-x} mixed
cyanide crystals. X is an alkali metal (K, Na or Rb) and Y is a spherical
halogen ion (Br, Cl or I). Critical thresholds x_c at which associated first
order ferroelastic transitions disappear are calculated exactly. The diluted
random field is shown to compete with compressibility in making the transition
first order. Transitions are then found to remain first order down to x_c
except in the case of bromine dilution where they become continuous. All the
results are in excellent agreement with available experimental data.Comment: 10 pages, late
Opinion dynamics in a three-choice system
We generalize Galam's model of opinion spreading by introducing three
competing choices. At each update, the population is randomly divided in groups
of three agents, whose members adopt the opinion of the local majority. In the
case of a tie, the local group adopts opinion A, B or C with probabilities
alpha, beta and (1-alpha-beta) respectively. We derive the associated phase
diagrams and dynamics by both analytical means and simulations. Polarization is
always reached within very short time scales. We point out situations in which
an initially very small minority opinion can invade the whole system.Comment: To appear in European Physical Journal B. A few errors corrected,
some figures redrawn from the first versio
Rational Group Decision Making. A random field Ising model at T=0
A modified version of a finite random field Ising ferromagnetic model in an
external magnetic field at zero temperature is presented to describe group
decision making. Fields may have a non-zero average. A postulate of minimum
inter-individual conflicts is assumed. Interactions then produce a group
polarization along one very choice which is however randomly selected. A small
external social pressure is shown to have a drastic effect on the polarization.
Individual bias related to personal backgrounds, cultural values and past
experiences are introduced via quenched local competing fields. They are shown
to be instrumental in generating a larger spectrum of collective new choices
beyond initial ones. In particular, compromise is found to result from the
existence of individual competing bias. Conflict is shown to weaken group
polarization. The model yields new psycho-sociological insights about consensus
and compromise in groups.Comment: 25 pages, late
The dynamics of opinion in hierarchical organizations
We study the mutual influence of authority and persuasion in the flow of
opinion. Many social organizations are characterized by a hierarchical
structure where the propagation of opinion is asymmetric. In the normal flow of
opinion formation a high-rank agent uses its authority (or its persuasion when
necessary) to impose its opinion on others. However, agents with no authority
may only use the force of its persuasion to propagate their opinions. In this
contribution we describe a simple model with no social mobility, where each
agent belongs to a class in the hierarchy and has also a persuasion capability.
The model is studied numerically for a three levels case, and analytically
within a mean field approximation, with a very good agreement between the two
approaches. The stratum where the dominant opinion arises from is strongly
dependent on the percentage of agents in each hierarchy level, and we obtain a
phase diagram identifying the relative frequency of prevailing opinions. We
also find that the time evolution of the conflicting opinions polarizes after a
short transient.Comment: 6 pages, 5 figures, submitted to Phys. Rev.
The role of inflexible minorities in the breaking of democratic opinion dynamics
We study the effect of inflexible agents on two state opinion dynamics. The
model operates via repeated local updates of random grouping of agents. While
floater agents do eventually flip their opinion to follow the local majority,
inflexible agents keep their opinion always unchanged. It is a quenched
individual opinion. In the bare model (no inflexibles), a separator at 50%
drives the dynamics towards either one of two pure attractors, each associated
with a full polarization along one of the opinions. The initial majority wins.
The existence of inflexibles for only one of the two opinions is found to shift
the separator at a lower value than 50% in favor of that side. Moreover it
creates an incompressible minority around the inflexibles, one of the pure
attractors becoming a mixed phase attractor. In addition above a threshold of
17% inflexibles make their side sure of winning whatever the initial conditions
are. The inflexible minority wins. An equal presence of inflexibles on both
sides restores the balanced dynamics with again a separator at 50% and now two
mixed phase attractors on each side. Nevertheless, beyond 25% the dynamics is
reversed with a unique attractor at a fifty-fifty stable equilibrium. But a
very small advantage in inflexibles results in a decisive lowering of the
separator at the advantage of the corresponding opinion. A few percent
advantage does guarantee to become majority with one single attractor. The
model is solved exhaustedly for groups of size 3.Comment: 18 pages, 12 figure
- …