Issue
EPL
Volume 87, Number 3, August 2009
Article Number 38003
Number of page(s) 6
Section Interdisciplinary Physics and Related Areas of Science and Technology
DOI http://dx.doi.org/10.1209/0295-5075/87/38003
Published online 21 August 2009
EPL, 87 (2009) 38003
DOI: 10.1209/0295-5075/87/38003

Disconnected-connected network transitions and phase separation driven by co-evolving dynamics

O. Gräser1, C. Xu2 and P. M. Hui1

1   Department of Physics and Institute of Theoretical Physics, The Chinese University of Hong Kong Shatin, Hong Kong, China
2   School of Physical Science and Technology, Soochow University - Suzhou 215006, China

graeser@phy.cuhk.edu.hk
cxu@suda.edu.cn
pmhui@phy.cuhk.edu.hk

received 27 May 2009; accepted in final form 20 July 2009; published August 2009
published online 21 August 2009

Abstract
A general model that involves agents competing in an evolutionary game and an adaptive networking environment is proposed and studied. Using the snowdrift game as an example, an agent may switch character or rewire the connection when the actual payoff is less than what the agent expected of its character. Depending on the value of a payoff parameter and the initial fraction of cooperators, the system shows two distinct phases: A frozen phase, in which all non-cooperative agents are expelled as isolated agents from clusters of cooperators, and a phase in which agents of different characters form a connected network that continues to evolve. The connectivity of agents of different characters differs significantly in both phases. A theory that treats the two characters separately is constructed. The theory captures the co-evolving dynamics driven disconnected-connected network transition, the phase separation, the phase diagram, and how the system evolves in time.

PACS
87.23.Kg - Dynamics of evolution.
89.75.Fb - Structures and organization of complex systems.
05.65.+b - Self-organized systems.

© EPLA 2009