All the world’s a stage and the stage itself is space-time where all the laws of physics are merely players. But maybe space-time is not the fundamental aspect that it is believed to be. A team of researchers from Japan’s RIKEN suggests that space-time could emerge from quantum properties, and one in particular that is involved in it is called quantum magic.
That is not something out of a Marvel movie despite sounding like it. It is actually a mathematical measure of how difficult is to simulate a quantum state on a regular (read that as non-quantum) computer. It turns out that apart from the simplest quantum states, anything with a bit of chaos will end up being maximally magical, which is a wonderful mathematical euphemism for we can’t model them.
How does that relate to space-time? Well, there is a quantum theory that needed an extra ingredient and that particular flavor might be quantum magic. The theory is called bulk quantum gravity and it was proposed in the 1990s to try to reconcile gravitational and quantum theories. A requirement is that space-time is something that emerges from the theory, not something that is assumed a priori.
“Physicists have long been fascinated about the possibility that space and time are not fundamental, but rather are derived from something deeper,” lead author Kanato Goto of the RIKEN Interdisciplinary Theoretical and Mathematical Sciences, said in a statement.
A pragmatic analogy of the bulk theory is imagining an infinite cylinder (the bulk in question) holding objects that are acted on by gravity, such as a planet, a star, or more excitingly a black hole. The sleight of hand is that it is possible to consider the properties of particles on the surface of the cylinder to describe the gravitational theory that is happening inside.
“This relationship indicates that spacetime itself does not exist fundamentally, but emerges from some quantum nature,” added Goto. “Physicists are trying to understand the quantum property that is key.”
At first, researchers considered quantum entanglement of these surface particles as the crucial quantity to explain the connection, but it doesn’t fully cover the properties of gravity. In particular, the way black holes appear to destroy information, which the team approached as a manifestation of chaos. And from that chaos, they made a connection to quantum magic.
“This finding suggests that magic is strongly involved in the emergence of spacetime,” Goto argued.
It will be interesting to see what predictions and expectations this bulk quantum magic theory of gravity has – but for now, it is fun to just say its name.
The study is published in Physical Review D.