Topical Team lead Gravitational Decoherence of Entanglement

Short Description

Starting point / motivation

Space-based quantum communication as a whole, and an experiment which aims to detect decoherence of a correlated quantum state in the presence of a gravitational field specifically, entirely rely on the presence of quantum entanglement. The “Space-QUEST” mission at ESA level proposes a scenario where a special entangled photon source is located on ground.

One of the pair photons is measured there while its partner photon is transmitted to a space-based receiver on-board the ISS. The gravitational field of earth should alter the quantum entangled state and will thus make a quantum effect (decoherence) induced by gravity measureable for the first time.

This effect has been predicted in the scientific literature only recently. Observing such a new phenomenon could become the corner stone of a new theory describing both quantum physics and gravity – a long standing problem in contemporary physics. Rupert Ursin and his team, as the coordinator of ESA’s Topical Team (TT) behind Space-QUEST, were leading the effort to distil a concise experimental scientific requirement (ESR) document, describing the mission in all details.

This document has also been submitted with this call as an applicable document [FFG eCall Attachment to this proposal]. Based on the ESR document, ESA is implementing a phase A/B study within ELIPS-4 together with the space industry to implement a space segment only. The ground segment (source, detectors, telescope, …) will be implemented by the science team separately and needs funds independent from those of ESA.

Contents and goals

The goal of the TT-GRADE project proposal is to develop the mission further and bundle the inputs of the TT’s 42 international experts concerned with the Space-QUEST mission’s ESR. Since the TT forms the central hub for all scientific and technological considerations, this task is of utmost importance for the success of all implementation phases.


New technological insights during these phases by the industry as well as by the implementing science team shall be scientifically processed and made available to everyone.

We will organize workshops, will participate to meeting with ESA and the industrial consortium and will review submitted documents in the industrial study, to guarantee a successful experiment finally in space. Until the ministerial conference, we propose to leave the management work package alive, to actively support the European partners as well as their respective agencies, to sign up for further phases of the experiments as well as to commit themselves to conduct the experiment finally in space.

Expected results

We are convinced that this project will be the key to keeping the scientific lead within an ESA project in Austria and to provide vital input to the studies performed at ESA level. Ultimately, we will contribute to lowering the risk of any failure during the implementation phase substantially, further ensuring that Space-QUEST will become a great success.

This project provides the recourses and supports the prime of a science mission at the ESA level. What is proposed here is the absolute minimum what makes a lead possible. The support is absolutely necessary.


Project Partners


Austrian Academy of Sciences - Institute for Quantum Optics and Quantum Information

Contact Address

Austrian Academy of Sciences
Institute for Quantum Optics and Quantum Information
Dr. Rupert Ursin
Boltzmanngasse 3
A-1090 Vienna