Can Choices Curve Spacetime?
There are hints that observers may be able to act on spacetime, not only by their physical properties, but also by their choices. As bizarre as this sounds, the idea stems from frameworks that bring quantum mechanics — the physics governing the microscopic realm — into the spacetime picture. These are being given a fresh spin by two independent groups of physicists. Giovanni Amelino-Camelia, of the University of Naples Federico II, in Italy, is leading one approach to examine whether quantum-gravitational effects might one day be detectable, manifesting in the way that different observers, Alice and Bob, disagree about their measurements of the same events. Meanwhile Caslav Brukner, of the Institute for Quantum Optics and Quantum Information in Vienna, Austria, and colleagues are calculating what would happen if Alice and Bob’s laboratories are themselves put into a quantum ‘superposition’ — in which the labs are in more than one physical state at the same time.