Against intuition
When I was studying physics in the 1990s, the matter was taken for granted. Our professors unanimously predicted that all four known fundamental forces of nature - the electromagnetic, the strong and the weak nuclear force as well as gravitation - could be combined in one overarching theory. Already in the introductory lecture we were given two reasons for this assumption: On the one hand, this simply requires "physical intuition". And on the other hand, almost everything has already been achieved on the way to unification; only gravity adorn itself.
Indeed, 20th century physics is a success story of unification. After James Clerk Maxwell had previously understood magnetism and electricity as two phenomena with a common origin, Sheldon Lee Glashow, Steven Weinberg and Abdus Salam developed a model in the late 1960s that elegantly combines the weak and electromagnetic interactions into the "electroweak force". This in turn could be expanded in the following decades with the strong nuclear force to the acclaimed and experimentally very well substantiated standard model of elementary particles. Only the fourth of the fundamental interactions, gravitation - described by Einstein's general theory of relativity - was still left out. A whole generation of physicists later, this is still the case. All attempts to set up an ultimate "world formula" failed despite immense effort. Is it possible that gravity cannot be traced at all? Does "physical intuition" turn out to be wishful thinking?
No one has to make such a judgment yet. Perhaps the theoreticians, inspired by past successes, simply took the wrong path when they tried to quantize gravity as well, after they had succeeded in doing so for all other fundamental forces. Our author Antoine Tilloy therefore takes a different approach. Starting on page 12, the researcher from the Max Planck Institute for Quantum Optics in Garching near Munich presents a new theory that combines the theory of relativity and quantum physics in such a way that gravity retains its classic character.
Wishing you an inspiring read
Your
Carsten Könneker
