arXiv:2501.18787 · Nonlinearity
Quantitative derivation of the two-component Gross–Pitaevskii equation in the hard-core limit with uniform-in-time convergence rate
Jacky J. Chong, Jinyeop Lee, Zhiwei Sun
Abstract
Abstract We derive, in the Gross–Pitaevskii (GP) limit, the time-dependent two-component GP equation as an effective description of the dynamics of a dilute two-component Bose gas near its ground state, which exhibits a two-component Bose–Einstein condensate. Our main result establishes a uniform-in-time bound on the convergence rate between the many-body dynamics and the effective description, explicitly quantified in terms of the particle number N . This improves upon the works of Michelangeli and Olgiati 2014 J. Nonlinear Math. Phys. 24 466–4; Olgiati 2017 Effective Non-Linear Dynamics of Binary Condensates and Open Problems pp 239–56) by providing a sharper, N -dependent, time-independent convergence rate, and also implies a uniform-in-time bound for the one-component case. Furthermore, our approach extends the framework of Benedikter et al (2015 Commun. Pure Appl. Math., 68 1399–482) to the multi-component Bose gas in the hard-core limit setting. More specifically, we develop the necessary Bogoliubov theory to analyze the dynamics of multi-component Bose gases in the GP regime.