Central limit theorems for additive functionals of long-range zero-range processes
Xue Xiaofeng
TL;DR
The paper extends the central limit theorem for additive functionals of nearest-neighbor zero-range processes to long-range interactions on $\mathbb{Z}^d$ with kernel $\|y-x\|_2^{-(d+\alpha)}$. By leveraging a local central limit theorem for the long-range random walk and a relaxation-to-equilibrium principle, it derives dimension- and parameter-dependent CLTs in which the limit processes are Brownian motion or fractional Brownian motion with Hurst parameters in $(\tfrac12, \tfrac34]$, depending on $(d,\alpha)$. The analysis employs a martingale decomposition (Kipnis–Varadhan) and a Poisson-flow approach to control the additive functionals, with explicit normalizations $\Lambda_{d,\alpha}(N)$ and variance factors $\sigma_\gamma(V)$ that encode the effect of long-range jumps and the equilibrium fluctuations. The results unify and extend prior nearest-neighbor results (Quastel 2002) and align with related findings for long-range interacting systems, highlighting phase-transition-like changes in the scaling and limiting behavior as $\alpha$ varies. Overall, the work provides a comprehensive framework for understanding temporal fluctuations in long-range zero-range dynamics and their connections to fractional Brownian limits.
Abstract
In this paper, we extend the central limit theorem of the additive functional of the nearest-neighbor zero-range process given in \cite{Quastel2002} to the long-range case. Our main results show that in several cases the limit processes are driven by fractional Brownian motions with Hurst parameters in $(1/2, 3/4]$. A local central limit theorem of the long-range random walk and a relaxation to equilibrium theorem of the long-range zero-range process play the key roles in the proofs of our main results.
