Science
Maldacena Claims Observers Are Required in Quantum Gravity Theory
Theories of Everything
Juan Maldacena: Geometry as Entanglement, and the Emergence of Spacetime
"There is no view from nowhere in quantum gravity. You require an observer. When you consider a slightly more complicated discussion where you include an observer that is moving in this space, so you don't just do the empty space, but you do the space with the observer, then the entropy becomes positive. Putting an observer, a real observer that is there in the system, solves this problem with the imaginary numbers that were appearing."
Juan Maldacena, author of the most-cited paper in theoretical physics, argues that quantum gravity cannot be formulated from a perspective outside the system. In perturbative quantum gravity calculations for de Sitter space, certain entropy quantities yield imaginary or negative values unless a physical observer is included in the equations. This suggests that measurement and observation are fundamentally embedded in the structure of spacetime at the quantum level, not external to it.
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Theories of Everything