We are concerned with the Cauchy problem of the compressible quantum Euler system with damping in \(\mathbb {R}^d\ (d\ge 1)\) . Compared with [12], we establish the local well-posedness of solutions near constant equilibrium in the critical regularity functional framework. Furthermore, we develop a new craftsmanship condition for generally hyperbolic systems with symmetric damping and Korteweg-type dispersion, which enables us to prove the global-in-time well-posedness within the regime of small data. The so-called “gauge” function technique is mainly employed to overcome the possible derivative loss in energy estimates. Finally, we derive optimal time-decay estimates of solutions by the time-weighted Lyapunov energy method, under the assumption that the low-frequency part of the initial perturbation is bounded in \({\dot{B}}^{-\sigma _1}_{2,\infty }\) with \(\sigma _1\in (-d/2, d/2]\) .
