Derivation of the Chern-Simons-Schrödinger equation from the dynamics of an almost-bosonic-anyon gas
Théotime Girardot, Jinyeop Lee
TL;DR
This work derives the Chern--Simons--Schrödinger (CSS) equation as the effective dynamics for an almost-bosonic extended-anyon gas in the large-$N$ limit. Using the particle-counting method of Pickl–Knowles, the authors show that, for finite times and small coupling $|eta|$, the $N$-body evolution with regularized radius $R=(\log N)^{-1/2+\varepsilon}$ remains close to a product state driven by CSS$(R,u_0)$, ultimately converging to CSS$(u_0)$ as $R\to0$ with a rate controlled by $|\,\log R|$. The analysis introduces novel controls of logarithmic divergences through Hardy-type inequalities and Grönwall-type estimates for condensate depletion and kinetic energy, enabling a rigorous link between microscopic anyon dynamics and the emergent CSS macroscopic behavior. These results provide the first derivation of CSS from a many-body anyon system, highlighting the role of the extended-anyon regularization and finite-time validity, and setting the stage for potential extensions to larger coupling or different regularizations.
Abstract
We study the time evolution of an initial product state in a system of almost-bosonic-extended-anyons in the large-particle limit. We show that the dynamics of this system can be well approximated, in finite time, by a product state evolving under the effective Chern--Simons--Schrödinger equation. Furthermore, we provide a convergence rate for the approximation in terms of the radius $R = (\log N)^{\frac{1}{2}+\varepsilon}$ of the extended anyons. These results establish a rigorous connection between the microscopic dynamics of almost-bosonic-anyon gases and the emergent macroscopic behavior described by the Chern--Simons--Schrödinger equation.
