
How Our Universe Could Emerge as a Hologram
Reprinted with permission from Quanta Magazine’s Abstractions blog.Physicists have devised a holographic model of “de Sitter space,” the term for a universe like ours, that could give us new clues about the origin of space and time.Drawing by Xi DongThe fabric of space and time is widely believed by physicists to be emergent, stitched out of quantum threads according to an unknown pattern. And for 22 years, they’ve had a toy model of how emergent spacetime can work: a theoretical “universe in a bottle,” as its discoverer, Juan Maldacena, has described it.The spacetime filling the region inside the bottle—a continuum that bends and undulates, producing the force called gravity—exactly maps to a network of quantum particles living on the bottle’s rigid, gravityfree surface. The interior “universe” projects from the lowerdimensional boundary system like a hologram. Maldacena’s discovery of this hologram has given physicists a working example of a quantum theory of gravity.But that doesn’t necessarily mean the toy universe shows how spacetime and gravity emerge in our universe. The bottle’s interior is a dynamic, Escheresque place called anti–de Sitter (AdS) space that is negatively curved like a saddle. Different directions on the saddle…Read More…
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