Quantum gravity: new results from IceCube and Fermi data

In a ground-breaking research study featured in Nature Astronomy, a collaborative research team from the University of Naples "Federico II," the University of Wroclaw, and the University of Bergen explored a quantum gravity model. This model suggested that the velocity of ultrarelativistic particles lessens as their energy increases. Though this effect is minuscule, proportional to the energy-to-Planck-scale ratio of the particle, it can become noticeable when observing distant astrophysical sources.

The researchers used gamma-ray flashes from the Fermi telescope and high-energy neutrinos from the IceCube Neutrino Observatory to test their hypothesis. They believed that some neutrinos and gamma-ray flashes might share a common origin. However, they appear at different times due to a reduction in velocity based on energy.

Lead author, Professor Giovanni Amelino-Camelia from the University of Naples, representing the team, stated, "We found initial evidence supporting quantum gravity models that predict this effect by merging data from IceCube and Fermi. This discovery is a significant advancement in quantum gravity research, marking the first instance of evidence supporting quantum gravity at this statistical data level."

Amelino-Camelia added, "While these findings are early-stage, they lay a robust foundation for more in-depth future investigations. As we gather more data from our gamma-ray and neutrino telescopes, even if the effect is not confirmed, our results will still provide strict limits on the relevant model parameters. This in itself is a unique and noteworthy achievement in quantum gravity research."

More info: Giovanni Amelino-Camelia et al, Could quantum gravity slow down neutrinos?, Nature Astronomy (2023). DOI: 10.1038/s41550-023-01993-z . www.nature.com/articles/s41550-023-01993-z