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Title: On effective temperature in network models of collective behavior

Journal Article · · Chaos (Woodbury, N. Y.)
DOI:https://doi.org/10.1063/1.4946775· OSTI ID:22596866
 [1];  [2]
  1. Department of Mechanical and Aerospace Engineering, New York University, Brooklyn, New York 11201 (United States)
  2. Department of Mathematics, Bar-Ilan University, 5290002 Ramat-Gan (Israel)

Collective behavior of self-propelled units is studied analytically within the Vectorial Network Model (VNM), a mean-field approximation of the well-known Vicsek model. We propose a dynamical systems framework to study the stochastic dynamics of the VNM in the presence of general additive noise. We establish that a single parameter, which is a linear function of the circular mean of the noise, controls the macroscopic phase of the system—ordered or disordered. By establishing a fluctuation–dissipation relation, we posit that this parameter can be regarded as an effective temperature of collective behavior. The exact critical temperature is obtained analytically for systems with small connectivity, equivalent to low-density ensembles of self-propelled units. Numerical simulations are conducted to demonstrate the applicability of this new notion of effective temperature to the Vicsek model. The identification of an effective temperature of collective behavior is an important step toward understanding order–disorder phase transitions, informing consistent coarse-graining techniques and explaining the physics underlying the emergence of collective phenomena.

OSTI ID:
22596866
Journal Information:
Chaos (Woodbury, N. Y.), Vol. 26, Issue 4; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 1054-1500
Country of Publication:
United States
Language:
English