Quantum quasi-neutral limits and isothermal Euler equations

Journal article

We provide a rigorous justification of the semiclassical quasi-neutral and the quantum many-body limits to the isothermal Euler equations. We consider the nonlinear Schrödinger–Poisson–Boltzmann system under a quasi-neutral scaling and establish the convergence of its solutions to the isothermal Euler equations. Different from the previous results that dealt with the linear Poisson equations, the system under our consideration accounts for the exponential nonlinearity in the potential. A modulated energy method is adopted, allowing us to derive the stability estimates and asymptotics. Furthermore, we focus our analysis on the many-body quantum problem via the von Neumann equation and establish a mean-field limit in one dimension by using Serfaty’s functional inequalities, thus connecting the quantum many-body dynamics with the macroscopic hydrodynamic equations. A refined analysis of the quasi-neutral scaling for the massless systems is presented, and the well-posedness of the underlying quantum dynamics is established. Moreover, the construction of well-prepared admissible initial data is obtained. Our results provide a rigorous mathematical analysis for the derivation of quantum hydrodynamic models and their limits, contributing to the broader understanding of interactions between quantum mechanics and compressible fluid dynamics.

Authors: Ben-Porat, I; Chen, GG; Yuan, D

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: IOP Publishing
• Journal: Nonlinearity
• Volume: 39
• Issue: 6
• Pages: 065005
• Article number: 065005
• Publication date: 2026-06-05
• Acceptance date: 2026-04-22
• DOI: 10.1088/1361-6544/ae638a
• EISSN: 1361-6544
• ISSN: 0951-7715
• Language: English
• Keywords: 35Q83, 82B40, 82D10, 35Q35, 35Q70, 35Q82; isothermal Euler equations; mean-field derivation; modulated energy; quantum many-body dynamics; quasi-neutral limit; Schrödinger–Poisson equations