XFEL to Cross Lasers for First Quantum Vacuum Detection — SkimNews
Get the Health newsletter
Daily health & science — research, biotech, public health, the studies worth knowing. Free.
- European XFEL researchers plan to cross the facility's pulsed X-ray beam with a 300-terawatt optical laser at the HIBEF research facility to detect vacuum birefringence, a 1930s prediction by Werner Heisenberg and Hans Euler.
- Felix Karbstein at the Helmholtz Institute Jena estimated that out of roughly 100 billion X-ray photons in a single XFEL pulse, only one would have its polarization flipped by the vacuum's quantum fields.
- Tom Cowan and colleagues devised a dark-field technique — placing a small circular object in the X-ray beam after the laser-strained region — to divert affected photons into a halo where a detector can spot them against the suppressed background.
- The HIBEF team completed a proof-of-principle run last year confirming the dark-field method blocks background X-rays, and researchers now hope to attempt their first real measurement next year.
- A 2013 ESO Very Large Telescope study detected polarization in light from a neutron star 400 light years away and attributed it to vacuum birefringence, but independent theorists disputed the neutron-star model assumptions required for that interpretation.
- NASA's Imaging X-ray Polarimetry Explorer strengthened the vacuum-birefringence case earlier this year, though its analysis still depends on neutron-star behavior models that the XFEL experiment is designed to bypass.
- QED has never been proved wrong and predicts the electron's magnetic moment to about 1 part in 1 trillion; a confirmed XFEL detection would push the theory into an uncharted intensity regime and could sharpen the experimental handle on dark matter.
Why it matters: For the first time, a lab experiment would test Heisenberg and Euler's 1930s vacuum-birefringence prediction with photons of known polarization before and after, removing the neutron-star-model uncertainty that still hangs over both the 2013 VLT claim and NASA's IXPE result. A confirmed detection validates QED in a new regime and offers a fresh experimental angle on dark matter.
Ask SkimNews
