pERFEcTO’s work-programme has been structured and organised to address the objectives highlighted in the summary in a systematic way.
1. Interface between gravity/spacetime and quantum physics:
In a work appeared in Class. Quantum Gravity, we have put forward a Hamiltonian description of the non-local dynamics of a mechanical quantum oscillator stemming from a hypothetical small-scale structure of spacetime — characteristic of several quantum gravity models. This represents the first step towards a detailed description of optomechanical experiments aimed at unveiling these effects or ruling out the underlying theories. Further work is in progress, in collaboration with the group of Prof Marin in Florence.
In a work appeared in Nat. Commun., we have explored the interplay between quantum and time physics investigating how the concept of time localizability is affected in presence of quantum clocks.
Finally, in a work appeared in Phys. Rev. Lett., we have combined spacetime physics with indefinite causal order and shown that particle detectors can, if in a quantum-controlled superposition, harvest correlations from the vacuum of a field theory otherwise not possible to harvest.
2. Foundations of quantum physics and the quantum-to-classical transition:
The superposition principle is one of the basic tenants of quantum mechanics whose tests at mesoscopic scales are made extremely difficult by the fragility of quantum features. Experiments aiming at probing this principle, and with it also possible modifications of quantum mechanics, are under intense investigation. In a result selected as Editors’ Suggestion in Phys. Rev. A, we have extended the framework of near-field interferometry to account for large test particles. This result opened the way to performing accurate forecasts for near-field interferometry experiments both ground and space-based. We have employed these results in a recent pre-print where we showed the possibilities and limitations of ground-based matter-wave experiments with large nanoparticles.
In another recent pre-print, we have investigated the potential of Quantum Hypothesis Testing — a scheme that uses the notorious statistical inference techniques in combination with quantum resources — for studies of fundamental physics employing optomechanical set-ups. This study shows that quantum squeezed light offers an inference advantage with respect to comparable classical strategies.
3. Quantum physics and thermodynamics:
The interplay between quantum measurements and thermodynamics of quantum processes has been another pillar of pERFEcTO. In a work appeared in npj Quantum Inf., we have formulated a phase-space framework to account for the thermodynamic effect of continuously monitoring a quantum system. Successively, this framework has led to the first experimental assessment of irreversible entropy production in a mechanical mesoscopic quantum system, a result appeared as Editors’ Suggestion in Phys. Rev. Lett.
Quantum measurements are crucial ingredients also when it comes to characterising the statistic of relevant physical quantities, like work or entropy production. In a recent pre-print, we have proposed a change of paradigm with respect to the celebrated two-point measurement scheme -- used to verify the validity of the fluctuation theorem in quantum systems -- with a novel one-point measurement scheme. Our scheme does not lose information on the quantum coherence of the initial state of the process of interest, which is crucial for characterising the role of quantum correlations and coherence in the thermodynamics of quantum processes.
pERFEcTO has obtained several results at the frontiers of modern quantum physics. All these results have been disseminated via publications in top-tier peer-reviewed journals, social media (Twitter & Facebook dedicated accounts), a dedicated project website, and via seminars in academic institutions and participation at international conferences and workshops.
