Recent experiments have revealed that beyond-mean-field corrections are much more relevant in weakly-interacting dipolar condensates than in their non-dipolar counterparts. We show that in quasi-one-dimensional geometries quantum corrections in dipolar and non-dipolar condensates are strikingly different due to the peculiar momentum dependence of the dipolar interactions. The energy correction of the condensate presents not only a modified density dependence, but it may even change from attractive to repulsive at a critical density due to the surprising role played by the transversal directions. The anomalous quantum correction translates into a strongly modified physics for quantum-stabilized droplets and dipolar solitons. Moreover, and for similar reasons, quantum corrections of three-body correlations, and hence of three-body losses, are strongly modified by the dipolar interactions. This intriguing physics can be readily probed in current experiments with magnetic atoms.doi:10.1103/PhysRevLett.119.050403Introduction.-Quantum fluctuations introduce a shift of the ground-state energy of a Bose gas, which at first order is given by the well-known Lee-HuangYang (LHY) correction [1]. However, in the weaklyinteracting regime, experiments on Bose-Einstein condensates are well described within the mean-field approximation. The situation may be crucially different in the presence of competing interactions, as recently discussed in the context of Bose-Bose mixtures [2]. In that scenario, the interplay between inter-and intra-species interactions results, at the verge of mean-field instability, in a dominant LHY correction well within the weaklyinteracting regime. The LHY correction may stabilize a collapsing condensate, resulting in the formation of quantum droplets, a novel ultra-dilute liquid whose surface tension is provided by purely quantum effects.

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