Eur. Phys. J. B (2012) 85: 197
https://doi.org/10.1140/epjb/e2012-20681-6

Regular Article

A comparison between the quasi-species evolution and stochastic quantization of fields

¹ Department of Physics, Northeastern University, Boston, 02115 Massachusetts, USA
² Institut für Physik, Technische Universität Dortmund, 44221 Dortmund, Germany

^a e-mail: ginestra.bianconi@gmail.com

Received: 20 August 2011
Received in final form: 29 March 2012
Published online: 18 June 2012

Abstract

The quasi-species equation describes the evolution of the probability that a random individual in a population carries a given genome. Here we map the quasi-species equation for individuals of a self-reproducing population to an ensemble of scalar field elementary units undergoing a creation and annihilation process. In this mapping, the individuals of the population are mapped to field units and their genome to the field value. The selective pressure is mapped to an inverse temperature β of the system regulating the evolutionary dynamics of the fields. We show that the quasi-species equation if applied to an ensemble of field units gives in the small β limit can be put in relation with existing stochastic quantization approaches. The ensemble of field units described by the quasi-species equation relaxes to the fundamental state, describing an intrinsically dissipative dynamics. For a quadratic dispersion relation the mean energy ⟨U⟩ of the system changes as a function of the inverse temperature β. For small values of β the average energy ⟨U⟩ takes a relativistic form, for large values of β, the average energy ⟨U⟩ takes a classical form.