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Our paper “The meaning of redundancy and consensus in quantum objectivity” just appeared on Quantum

A quantum state is said to be objective if multiple observers are able to recover information about the state and agree among themselves. This is in turn possible only if said information was encoded multiple times into the surrounding environment. In this paper, we show how it is not always possible for the observers to extract all of the relevant information that was initially encoded into the environment. We do this by introducing two quantities with a rigorous definition and a clear operative interpretation: “redundancy”, which quantifies how many times the information was written into the environment, and “consensus”, which is the maximum number of observers able to extract said information.

Article reference:

D.A. Chisholm, L. Innocenti, G.M. Palma, Quantum 7, 1074 (2023)

Link to the article: “https://quantum-journal.org/papers/q-2023-08-03-1074/”

Our paper “Collapse Dynamics Are Diffuse” just appeared on Physical Review Letters

Highlights

We show that any dynamics collapsing the wave function in space implies diffusion in momentum. This is relevant since it means that, in order to test the validity of thiesse models, and in general of the quantum superposition principle, one can perform experiments, known as “non-interferometric”, which look for this diffusion effect. The main advantage is that these kind of experiments do not require the creation of a large and stable superposition in space, which is typically very hard to do. This approach was successfully employed in the last decade to constrain the parameters of models of spontaneous wave function collapse and it ruled out the simplest version of the Diósi-Penrose model. Until now, one might have argued that the diffusive effects were just a feature of the specific models considered. In this article, we show that this is not the case: ny space-translation covariant dynamics that complies with the no-signaling constraint, if collapsing the wave function in space, must change the average momentum of the system and/or its spread.

Article reference:

S. Donadi, L. Ferialdi and A. Bassi, Collapse Dynamics Are Diffuse, Phys. Rev. Lett. 130, 230202 (2023).

Link to the article: “https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.130.230202”

EIC Pathfinder grant award to QuCoM

News

The University of Southampton, the Queen’s University Belfast and the University of Trieste have come together, after a 4.5 year project called TEQ (Horizon H2020), with a new Consortium to present to the European Commission a new project proposal in the frame of the HORIZON-EIC-2021-PATHFINDEROPEN-01-01 call. Together with the University of Leiden, Leiden Cryogenics S BV and Leiden Spin Imaging, the consortium consists of two experimentalists, two theorists, and two SMEs.

The project, named QuCoM, was submitted to the Commission in May 2021 and has received a positive evaluation.

The main objective of QuCoM is to demonstrate the proof of concept (TRL 1) of a levitated acceleration sensor and its ability detecting gravity of small masses and in the quantum controlled regime. Toward this objective the Consortium will explore the interplay between quantum mechanics and gravity in a parameter range accessible for cost-effective table-top experiments. Also, partners will investigate quantum superpositions in which these masses are delocalized and address some of the most popular theoretical proposals combining quantum physics and gravity in a nonstandard fashion. The proposed experiments will assess their limits of validity and/or further constrain the values of their parameters.

The experiments in question will be performed with optically and magnetically trapped micro/nano-particles based on the experimental expertise of partners in the consortium. Levitated mechanics experiments at Southampton have been already picked up by the EU Innovation Radar within the TEQ project. The state preparation, control and analysis schemes are based on the expertise of the theory partners.

QuCoM will also have a high technological impact and will play a big role in innovation. High-tech SMEs will contribute in optimizing the experimental apparatus for fulfilment of the targeted objectives, which will in turn put them in a position to offer their improved products in sub mK, low vibration cryogenic equipment to market. In particular, the LSI will explore, together with University of Leiden, the feasibility of implementing our technology into a micro-satellite platform for space-based metrology and Earth Exploration utilizing gravitational detection.

With a total grant amount of 2 753 179,00 Euros, the project will last 3 years.

Our paper “The meaning of redundancy and consensus in quantum objectivity” just appeared on Quantum

Our paper “Collapse Dynamics Are Diffuse” just appeared on Physical Review Letters

EIC Pathfinder grant award to QuCoM

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