Quantum Techniques for Studying Equilibrium in Reaction Networks

Anderson, Craciun, and Kurtz have proved that a stochastically modelled chemical reaction system with mass-action kinetics admits a stationary distribution when the deterministic model of the same system with mass-action kinetics admits an equilibrium solution obeying a certain "complex balance" condition. Here we present a proof of their theorem using tools from the theory of second quantization: Fock space, annihilation and creation operators, and coherent states. This is an example of "stochastic mechanics", where we take techniques from quantum mechanics and replace amplitudes by probabilities.