HIDEAS aims at a breakthrough in the information capacity of Quantum Communication (QC), well beyond the standard single-mode approach, by exploiting the intrinsic multi-modal and multivariate character of the radiation field. Our long term vision is that of a broadband Quantum Communication, where all the physical properties of the photons are utilized to store information. Working at the quantum level requires i) to produce quantum entanglement of light in high dimensional and multivariate spaces and ii) to create multimode quantum interfaces between light and matter in order to store high-D quantum states of light in long-lived matter degrees of freedom. Beneficial impacts will be also on Quantum Metrology. As crucial steps towards these objectives we propose five research lines:WP1 aims at bringing to the quantum realm the spectacular progress achieved by the introduction of frequency combs in the classical domain.WP2 aims at realizing sources of multimode spatially entangled light appropriate for paving the way to parallel quantum communication and information processing.WP3 aims at realizing a very high-D entanglement between twin photons produced by parametric down- conversion (PDC). It focuses on the conjugate variables angle and optical angular momentum (OAM), providing a larger alphabet for QC and a more robust non-locality.WP4 explores the non-factorable spatio-temporal X-structure of light entanglement in PDC, opening an avenue that offers unique access to the full broad band of PDC.WP5 exploits various forms of multimode light-matter entanglement, to realize multi-modal light-atom quantum interfaces and a parallel quantum memory for light (quantum hologram), with resolution and memory capacity exceeding those of classical holograms.The consortium gathers an unparalleled expertise in measuring and manipulating OAM, in generating/controlling quantum effects in multi-mode PDC and in realizing light-matter quantum interfaces.