“Programming the Universe,” by Seth Lloyd
Welcome to the Machine
Review by COREY S. POWELL
. . .
More than once, I found myself recalling a scene in “Animal House” in which one of the Delta House guys has a cosmic epiphany during a cannabis-fueled conversation with his professor (Larry: “That means that one tiny atom in my fingernail could be. . . .” Professor: “. . . could be one little, tiny universe.” Pause. Larry: “Could I buy some pot from you?”) Is Lloyd doing anything more than playing physics head games? He anticipates the question, asking, “Just what does this picture of the universe as a quantum computer buy me that I didn’t already have” thanks to our “perfectly good quantum-mechanical theory of elementary particles?” For one thing, he answers, it could be a powerful new research tool. One of Lloyd’s M.I.T. colleagues, David Cory, has used a simple quantum computer to study how information flows through the subatomic world. If these devices truly match the workings of the universe, expanded versions could be used, for example, to develop a more complete theory of gravity, whose essence is still utterly mysterious. . . .