Genuine Multipartite Entanglement in Positronium - A Potential Quantum Sensor for Detecting Cancer


The electron-positron annihilation into two photons is a standard technology in medicine to observe e.g. metabolic processes in human bodies. A new tomograph will provide the possibility to observe not only direct e+e− annihilations but also the 3 photons from the decay of ortho-positronium atoms formed in the body.

In hospitals a PET, a Positron-Emission-Tomograph, servers as a device to determine spatial and temporal distributions of radio-active substances injected into patients. The formed positronium, a bound state of positron and electron, decays, however, also into three photons. This information was never read out and would provide not only local classical but also quantum information about the metabolic processes in human bodies, novel quantum sensors for e.g. detecting cancer can be developed.

In a Vienna-Cracow collaboration [1] it was derived that the three photons resulting from the positronium decays in human bodies are genuinely multipartite entangled, a very strong type of multipartite entanglement that involve all degrees of freedom. This holds even if all spin-states of ortho-positronium are mixed, interestingly, the GHZ-type of genuine multipartite entanglement is lost, however, not the Dicke-type of genuine multipartite entanglement. New technology, the J-PET, developed at the Jagiellonian University, will make it possible to reveal these entanglement properties of positronium.

[1] B.C. Hiesmayr and P. Moskal, Scientific Reports 7: 15349  (2017)