On the duality between particles and polymers
Mustazee Rahman
TL;DR
The paper establishes a comprehensive duality between tasep-like particle systems and last passage percolation (LPP) polymers across Geometric, Exponential, and Brownian settings, using a variational (Hopf–Lax–Oleinik–style) framework. It develops a language and topology for LPP models, builds isomorphisms and space-time/space-noise dualities, and derives explicit determinantal formulas for fixed-time and fixed-boundary observables via Fredholm determinants with carefully constructed kernels. Key contributions include Johansson’s and Schütz’s determinant formulas, kernel mappings across model transitions, and rigorous limits that connect Geometric to Exponential to Brownian LPP, yielding corresponding tasep descriptions and Warren-type results. The work consolidates the KPZ-related connections between directed polymers and particle systems, providing deterministic identities and probabilistic tools to study fluctuations and limit shapes in (1+1)-dimensional growth.
Abstract
We explore the connection between tasep-like interacting particle systems and last passage percolation type polymer models, focusing on three models: Geometric, Exponential and Brownian last passage percolation and their associated tasep particle systems. We explain how formulas for certain natural observables in last passage percolation translate to formulas for tasep, by going through a notion of "duality". In turn, we obtain determinantal formulas for last passage percolation with a deterministic boundary and for tasep with a deterministic first particle trajectory.
