Theoretical Physics: The Man Who Does Tricks with Strings

Juan Maldacena with a set of mathematical equations is like a magician with a wand. He can take rows of arcane symbols that describe the gravitational weirdness of a black hole and, with a flourish, pull from them equations that look suspiciously like those that govern the will-o’-the-wisp interactions of subatomic particles. What’s more, the associate professor of physics at Harvard University can perform the same trick in reverse, effectively concealing the rabbit back inside the hat.

In this playful way, the 31-year-old native of Buenos Aires has been able to suggest a way to knit together two theories previously thought to be incompatible: quantum mechanics, which deals with the universe at its smallest scales; and Einstein’s general theory of relativity, which deals with the very largest. Even as an undergraduate at Argentina’s Instituto Balseiro, Maldacena had been intrigued by the idea that a bridge spanning the two might be constructed using string theory–so called because it assumes the fundamental constituents of matter are not pointlike particles but tiny, vibrating loops of string.

When Maldacena transformed his string-theory black hole into something resembling conventional particle physics, his colleagues reacted first with disbelief, then with delight, dancing and singing (in a spoof of the Macarena), “!Ehhhh, Maldacena!”

–By J. Madeleine Nash