November 1st, 2016
(written by lawrence krubner, however indented passages are often quotes). You can contact lawrence at: email@example.com
The reasoning behind the idea comes from several earlier discoveries by physicists, such as a 2006 paper by Shinsei Ryu and Tadashi Takayanagi showing a connection between entanglement and the geometry of spacetime. Building on that work, in 2013 Juan Maldacena and Leonard Susskind found that if two black holes became entangled, they would create a wormhole—a shortcut in spacetime predicted by general relativity. This discovery (nicknamed ER=EPR, after physicists’ shorthand for wormholes and entanglement) and others like it suggest, surprisingly, that entanglement—which was thought to involve no physical link—can produce structures in spacetime.
To understand how entanglement might give rise to spacetime, physicists first must better understand how entanglement works. The phenomenon has seemed “spooky,” in the words of Albert Einstein, ever since he and collaborators predicted it in 1935. Lately scientists have been studying the various kinds of entanglement that can exist. For instance, conventional entanglement involves linking a single characteristic (such as a particle’s spin) in multiple particles of the same type spread out in space. But one could instead entangle multiple particles of a certain kind at one location with particles of a different kind at the same location. “That’s not entanglement in space,” Balasubramanian says. “I’ve come to realize that there are other forms of entanglement that turn out to be relevant for this project of reconstructing spacetime—conventional entanglement is not enough.” Scientists are also tackling the confusing complexities of entangling larger numbers of particles.