DecoXtreme · Decocherence of Levitated Microscopic Particles in Extreme Isolation

One of the most intriguing features of quantum mechanics is the superposition principle, which allows a quantum object to be in two classically distinguishable states “at the same time”. Levitated objects, like nanoparticles, are an exciting platform to put the superposition principle at test, with simultaneously large masses and delocalization distances. Recently, in 2020 and 2021, the center of mass motion of a levitated nanoparticle was experimentally cooled down to the quantum regime. To achieve this milestone, the experiment had to be performed in extreme isolation conditions (e.g., ultra-high vacuum). Now the field faces the challenge to promote the high-purity quantum ground state cooled state of the nanoparticle to a more complex quantum state, which can be subsequently used for applications. DecoXtreme, is a multidisciplinary study devoted to provide the theoretical framework that allows to push the experiments with levitated nanoparticles deep in the quantum regime, by improving the current theoretical description of decoherence, envisioning strategies to mitigate its effects, and certifying the quantum properties of the observed quantum phenomena. To achieve this goal, we propose to promote the description of decoherence to move beyond the memoryless and continous noise approximations, to design decoherence protected states exploiting collective properties of levitated objects, and to analyze how to quantumness has to be certified in extreme isolation conditions. If successful, our rigorous theoretical analysis combined with the corresponding experimentally realistic constraints will uncover the path to longer lifetimes for quantum superpositions and, ultimately, lead to a better understanding of the nature of quantum phenomena.