Abstract

Inspired by the works in [2] and [11] we introduce what we call k-th-order fluctuation fields and study their scaling limits. This construction is done in the context of particle systems with the property of orthogonal self-duality. This type of duality provides us with a setting in which we are able to interpret these fields as some type of discrete analogue of powers of the well-known density fluctuation field. We show that the weak limit of the k-th order field satisfies a recursive martingale problem that corresponds to the SPDE associated with the kth-power of a generalized Ornstein-Uhlenbeck process.

Highlights

  • In the context of interacting particle systems with a conserved quantity in [6, 12] one studies the time-dependent density fluctuation field X (n)(φ, η(n2t)) =1 nd/2 φ(x/n)(ηx(n2t) − ρ). x∈ZdHere φ denotes a test-function, and ηx the number of particles at site x ∈ Zd

  • In this paper we show exactly the emergence of a scenario of this type: within a general class of models with orthogonal polynomial self-duality we consider the fluctuation fields associated to orthogonal polynomials and prove that they converge, in the scaling limit, to the solution of a recursive system of martingale problems

  • Ωf = Ωk of configurations with a finite number of particles, the self-duality functions that we consider in this paper are functions Dρ : Ωf × Ω → R parametrized by the density ρ > 0 satisfying the following properties

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Summary

Introduction

In the context of interacting particle systems with a conserved quantity (such as the number of particles) in [6, 12] one studies the time-dependent density fluctuation field. In this paper we show exactly the emergence of a scenario of this type: within a general class of models with orthogonal polynomial self-duality we consider the fluctuation fields associated to orthogonal polynomials and prove that they converge, in the scaling limit, to the solution of a recursive system of martingale problems. We believe that this can be a first step in the direction of defining non-linear fields, such as the square of the density field, via approximation of the identity, i.e., via a singular linear observable (cf [11]) of the field constructed in our paper. The rest of the sections are devoted to the proof of Theorem 5.2

The infinite configuration process
The finite configuration processes
Orthogonal polynomial self-duality
Orthogonality: where
Fluctuation fields
The coordinate process
Product σ-finite reversible measures
The fluctuation fields in coordinate notation
Main result
Main theorem
Strategy of the proof
Inductive argument
Closing the equation for the carré-du-champ
Recursion relation for duality polynomials
Controlling the moments of the fields
The gradient of the fluctuation fields
Conclusion
Tightness
The γ1 term
The γ2 term
Modulus of continuity
Uniqueness
Tightness criterium
Full Text
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