2018-01-05 13:53:11 UTC
1. Spacetime doesn't exist.
2. Spacetime is doomed.
3. Spacetime has to be replaced by more primitive building blocks.
4. Spacetime has to reemerge from more primitive building blocks.
Nima Arkani-Hamed (06:09): "Almost all of us believe that space-time doesn't really exist, space-time is doomed and has to be replaced by some more primitive building blocks."
Nima Arkani-Hamed: "Fundamental physics started the 20th century with the twin revolutions of relativity and quantum mechanics, and much of the second half of the century was devoted to the construction of a theoretical structure unifying these radical ideas. Yet storm clouds are gathering, which point towards a new set of revolutions on the horizon in the 21st century. Space-time is doomed - how can it emerge from more primitive building blocks? And how is our macroscopic universe compatible with violent microscopic quantum fluctuations that seem to make its existence wildly implausible? In this talk I will describe these deep mysteries and outline some of our strategies for making progress on them." https://sites.google.com/a/umich.edu/lctp/other-activities/public-lectures/-the-future-of-fundamental-physics
To unify relativity and quantum mechanics means to reconcile irreconcilable concepts - Newton's absolute time and spacetime, the idiotic consequence of Einstein's 1905 false constant-speed-of-light postulate:
"The effort to unify quantum mechanics and general relativity means reconciling totally different notions of time. In quantum mechanics, time is universal and absolute; its steady ticks dictate the evolving entanglements between particles. But in general relativity (Albert Einstein's theory of gravity), time is relative and dynamical, a dimension that's inextricably interwoven with directions X, Y and Z into a four-dimensional "space-time" fabric." https://www.quantamagazine.org/20161201-quantum-gravitys-time-problem/
Perimeter Institute: "Quantum mechanics has one thing, time, which is absolute. But general relativity tells us that space and time are both dynamical so there is a big contradiction there. So the question is, can quantum gravity be formulated in a context where quantum mechanics still has absolute time?" https://www.perimeterinstitute.ca/research/conferences/convergence/roundtable-discussion-questions/what-are-lessons-quantum