Blow-up profile of rotating 2D focusing Bose gases

We consider the Gross-Pitaevskii equation describing an attractive Bose gas trapped to a quasi 2D layer by means of a purely harmonic potential, and which rotates at a fixed speed of rotation $\mathrm{\Omega }$. First we study the behavior of the ground state when the coupling constant approaches $a\mathrm{\_}\ast$ , the critical strength of the cubic nonlinearity for the focusing nonlinear Schr{"o}dinger equation. We prove that blow-up always happens at the center of the trap, with the blow-up profile given by the Gagliardo-Nirenberg solution. In particular, the blow-up scenario is independent of $\mathrm{\Omega }$, to leading order. This generalizes results obtained by Guo and Seiringer (Lett. Math. Phys., 2014, vol. 104, p. 141–156) in the non-rotating case. In a second part we consider the many-particle Hamiltonian for $N$ bosons, interacting with a potential rescaled in the mean-field manner $--a\mathrm{\_}N{N}^{2\beta --1}w(N^{\beta }x),with$w$apositivefunctionsuchthat$\int_{$\mathbb{R}$^2} w(x) dx = 1$. Assuming that $\beta <1\mathrm{/}2$ and that $a\mathrm{\_}N\to a\mathrm{\_}\ast$ sufficiently slowly, we prove that the many-body system is fully condensed on the Gross-Pitaevskii ground state in the limit $N\to \mathrm{\infty }$.