Our paper “Testing Whether Gravity Acts as a Quantum Entity When Measured” published on Physical Review Letters.
The work describe a multi-interferometer experimental setup that can, in principle, reveal the non-classicality of a spatial superposition-sourced gravitational field if an irreducible disturbance is caused by a measurement of gravity.
On 10th September 2024, a QuCoM Steering Committee took place among the PIs of QuCoM partner organization to discuss the development of upcoming deliverables and milestones. The participants also discussed the outcomes of the dissemination strategy and adjustment of the collection of information. The partners viewed the project video that was created by the group of the University of Southampton and published in late May 2024. The partners discussed the possibility to meet in person in the spring 2025 to discuss project progresses and results in view of the project end in September 2025. The overall evaluation of scientific progresses is positive while the management continues to work smoothly.
On 9th September 2024, a QuCoM scientific meeting took place in Trieste with the aim of updating on progress and defining next steps and new collaborations to achieve the objectives of the project. The following talks were given:
A total of 20 participants from all 7 project partners attended the meeting.
As part of the Dissemination Plan of QuCoM, the Consortium released a project video in May 2024. The scientific question and QuCoM’s approach to addressing this question are central to the video. The video aims to illustrate and communicate that QuCoM is a project testing gravity in a new way. It also explains why gravity needs to be tested and that gravity is not well understood on the small/quantum scale. Additionally, it highlights QuCoM’s approach of using levitated particles and explains the rationale behind this method. The final product is available for all project teams to distribute and disseminate through their channels as a project presentation to the general public, the scientific community and funding agencies potentially interested in financing further research connected to QuCoM.
The video was conceived and created by the Southampton node. Special thanks to Marion Cromb and Jakub Wardak.
The QuCoM consortium recently concluded its first review meeting on November 20, 2023, achieving significant progress in the various work packages outlined in the agenda.
The meeting, conducted remotely, commenced with a warm welcome by G. Kregar, who initiated the session with an introduction and tour du table, setting a collaborative tone for the discussions.
Key Highlights of the Agenda:
The successful outcome of the QuCoM Review Meeting I underscores the consortium’s commitment to advancing quantum research, fostering collaboration, and pushing the boundaries of scientific exploration.
Ario Altamura and Tommaso Feri join QuCoM in the University of Trieste node. We wish them good work!
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/”
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”
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.
