A rift runs deep through the heart of physics. The general theory of relativity, which describes gravity, clashes with quantum physics. In an effort to seal that physics fissure, untold numbers of physicists have spent their careers working to build a theory of quantum gravity.
“When we started, maybe 99 percent of our colleagues thought we were crackpots and that’s now down to maybe 70 percent,” quips Oppenheim, of University College London.
All known forces except gravity are formulated in terms of quantum physics. The prevailing view is that gravity will need to assimilate with its quantum colleagues. But gravity is different, Oppenheim argues. While other forces evolve within a landscape of spacetime, gravity is the warping of spacetime itself. So, Oppenheim says, “it is pretty unclear that it should have a quantum nature, in my view.”
Physicists have devised several “no-go” theorems that seemingly forbid a classical theory of gravity. Such theorems highlight inconsistencies, apparently fatal to the idea, that arise when classical gravity is applied to quantum particles. But it’s possible to get around those prohibitions by adding some randomness to the way that spacetime bends in response to quantum particles, Oppenheim reports December 4 in Physical Review X.
2023-12-08 08:00:00
Source from www.sciencenews.org