“when #light passes through a #vacuum, we don’t see a response from its fields at all, even if they are rife with #fluctuations. The fields are perfectly invisible – they might as well not be there.
Except, maybe we haven’t been looking hard enough. In the mid-1930s, when #QED was still in its infancy, the theorists Werner #Heisenberg and Hans #Euler showed that if light is strong enough, it should begin to strain the vacuum fields, such that they affect the passage of any more light passing through – an effect known as #VacuumBirefringence.”
#Quantum / #vacuum / #Hamburg / #Germany / #XRay / #lasers <https://www.newscientist.com/article/2586310-were-on-the-verge-of-seeing-the-quantum-vacuum-for-the-first-time/> (paywall) / <https://archive.md/hZmeK>
