Quantum mechanics provides, to date, the most accurate understanding of the microscopic world of atoms, molecules and photons. Many experiments have so far confirmed the accuracy of quantum mechanics in describing the properties of microscopic systems but in everyday life we do not observe any of the counterintuitive phenomena that are predicted to take place in the quantum world, superpositions above all. This is the core issue being addressed by the TEQ project: is the lack of observation of quantum coherence at the macroscopic level a manifestation of a breakdown of quantum linearity, or simply the consequence of the fact that no one so far was able to create a macroscopic quantum superposition?
The overall objective of TEQ is the identification of the fundamental limitations to the applicability of quantum mechanics towards the establishment of a novel paradigm for quantum-enhanced technology that makes use of large-scale devices. Specifically, the TEQ project will: deliver low-noise traps for NanoCrystals (NCs) compatible with a cryogenic environment; design and realize specific detection and cooling strategies for trapped charged NCs; demonstrate experimentally the effectiveness of non-interferometric tests of non-standard decoherence acting upon quantum superposition states of massive NCs ; deliver a theoretical platform of clear experimental applicability for the study of refined collapse models, macroscopic quantum effects, and the investigation of time-dilation decoherence; allow for the assessment, and the potential ruling out, of models for quantum gravity.
TEQ has made steps to enhance the experimental capability for testing noise predicted by CSL-type collapse models by levitated mechanical systems. We have explored technical options and did find solutions to trap nano- and micro-meter sized particles in low noise environments. We have used mechanical vibration isolation techniques and have found way to decouple the experimental systems from acoustic noise. We have developed a low-noise Paul trap with electronics to reduce the electromagnetic noise generated by the trap itself. We pioneered a completely new technology of Meissner traps based on type-1 superconductors in cryostats. TEQ has pushed the theoretical framework for the investigation of the potential effects of collapses to uncharted territories, providing new tools for the characterisation of macroscopicity of the state of mesoscopic quantum systems. In doing so, the project has allowed the fundamental understanding of the interplay between the size of a superposition and the mechanisms that could affect it in a detrimental manner, including those of a gravitational nature. The project has allowed the exploration of potential scenarios where such effects would be magnified, from the use of rotational degrees of freedom to the suitable exploitation of geometric and fabrication arrangements able to amplify the effects of a collapse mechanism.
