Dynamics of condensation in the symmetric inclusion process. (English) Zbl 1284.82042

Grosskinsky, Stefan; Redig, Frank; Vafayi, Kiamars

Electron. J. Probab. 18, Paper No. 66, 23 p. (2013).

Summary: The inclusion process is a stochastic lattice gas, which is a natural bosonic counterpart of the well-studied exclusion process and has strong connections to models of heat conduction and applications in population genetics. Like the zero-range process, due to attractive interaction between the particles, the inclusion process can exhibit a condensation transition. In this paper we present first rigorous results on the dynamics of the condensate formation for this class of models. We study the symmetric inclusion process on a finite set \(S\) with total number of particles \(N\) in the regime of strong interaction, i.e. with independent diffusion rate \(m=m_N \to 0\). For the case \(Nm_N\to\infty\) we show that on the time scale \(1/m_N\) condensates emerge from general homogeneous initial conditions, and we precisely characterize their limiting dynamics. In the simplest case of two sites or a fully connected underlying random walk kernel, there is a single condensate hopping over \(S\) as a continuous-time random walk. In the non-fully connected case several condensates can coexist and exchange mass via intermediate sites in an interesting coarsening process, which consists of a mixture of a diffusive motion and a jump process, until a single condensate is formed. Our result is based on a general two-scale form of the generator, with a fast-scale neutral Wright-Fisher diffusion and a slow-scale deterministic motion. The motion of the condensates is described in terms of the generator of the deterministic motion and the harmonic projection corresponding to the absorbing states of the Wright-Fisher diffusion.

MSC:

82C22	Interacting particle systems in time-dependent statistical mechanics
60K35	Interacting random processes; statistical mechanics type models; percolation theory
82C26	Dynamic and nonequilibrium phase transitions (general) in statistical mechanics
82C41	Dynamics of random walks, random surfaces, lattice animals, etc. in time-dependent statistical mechanics

Keywords:

inclusion process; condensation; coarsening dynamics; Wright-Fisher diffusion