Symbiotic two-species contact process.

Area of Science:

• Statistical Physics
• Mathematical Biology
• Complex Systems

Background:

• The contact process (CP) is a fundamental model for population dynamics on lattices.
• Understanding species interactions is crucial for ecological modeling.
• Symbiosis can significantly alter population dynamics and stability.

Purpose of the Study:

• To investigate the impact of symbiotic interactions on a two-species contact process.
• To determine how symbiosis affects the critical parameters and universality class of the CP.
• To explore the role of reduced death rates in maintaining populations.

Main Methods:

• Mean-field theory analysis.
• Extensive Monte Carlo simulations on a lattice.
• Field-theoretic arguments to support critical behavior conclusions.

Main Results:

• The critical creation rate (λ(c)(μ)) decreases with increasing symbiosis (μ).
• Symbiotic interactions promote species survival, lowering the extinction threshold compared to single-species CPs.
• Simulation results align with the directed percolation (DP) universality class, despite strong corrections to scaling.

Conclusions:

• Symbiosis effectively stabilizes populations in the contact process model.
• The system exhibits critical behavior belonging to the directed percolation universality class.
• The findings have implications for understanding ecological dynamics in systems with mutualistic interactions.