Large collections of interacting quantum particles pose a challenge due to the enormous number of microscopic parameters and the resulting difficulties in describing, detecting, and controlling their quantum states. At the same time, they also offer new opportunities for applications such as quantum computing, quantum simulation and precision measurements. In this talk, I will describe novel experimental techniques, developed over the past years, aiming at detecting and controlling quantum many body states at the level of individual quanta:
1) "Quantum microscopes" follow a top-down approach, where large clouds of ultracold imaged with full single-particle, temporal, and spatial resolution. This enabled access to a range of previously unobserved phenomena, including non-local parity-order, light-cone spreading, amplitude Higgs modes, and entanglement waves.
2) "Atom-by-atom assembly" follows a bottom-up idea, where we try to construct many-body systems from scratch using arrays of optical tweezers. I will introduce this brand new method and speculate about future developments.