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Decades after physicists happened upon a stunning mathematical coincidence, researchers are getting close to understanding the link between two seemingly unrelated geometric universes.
Gravitational waves have opened up new ways to test the properties of black holes — and Einstein’s theory of gravity along with them.
The renowned British physicist, who died at 76, left behind a riddle that could eventually lead his successors to the theory of quantum gravity.
The amount of energy infusing empty space seems too small to explain without a multiverse. But physicists have at least one alternative left to explore.
A recently proposed experiment would confirm that gravity is a quantum force.
The theoretical physicist Joe Polchinski, who died Feb. 2, left a tremendous professional and personal legacy, says a friend and collaborator.
For decades, physicists have struggled to create a quantum theory of gravity. Now an approach that dates to the 1970s is attracting newfound attention.
A complete classification could lead to a wealth of new materials and technologies. But some exotic phases continue to resist understanding.