2019-05-13, 12:17 PM
Could quantum mechanics explain the existence of space-time?
Tom Siegfried
Tom Siegfried
Quote:That sounds like entangled particles must be able to communicate faster than light. Otherwise it’s impossible to imagine how one of them could know what was happening to the other across a vast space-time expanse. But they actually don’t send any message at all. So how do entangled particles transcend the space-time gulf separating them? Perhaps the answer is they don’t have to — because entanglement doesn’t happen in space-time. Entanglement creates space-time.
At least that’s the proposal that current research in toy universes has inspired. “The emergence of space-time and gravity is a mysterious phenomenon of quantum many-body physics that we would like to understand,” Swingle suggests in his Annual Review paper. Vigorous effort by several top-flight physicists has produced theoretical evidence that networks of entangled quantum states weave the space-time fabric. These quantum states are often described as “qubits” — bits of quantum information (like ordinary computer bits, but existing in a mix of 1 and 0, not simply either 1 or 0). Entangled qubits create networks with geometry in space with an extra dimension beyond the number of dimensions that the qubits live in. So the quantum physics of qubits can then be equated to the geometry of a space with an extra dimension. Best of all, the geometry created by the entangled qubits may very well obey the equations from Einstein’s general relativity that describe motion due to gravity — at least the latest research points in that direction. “Apparently, a geometry with the right properties built from entanglement has to obey the gravitational equations of motion,” Swingle writes. “This result further justifies the claim that space-time arises from entanglement.”
Still, it remains to be shown that the clues found in toy universes with extra dimensions will lead to the true story for the ordinary space-time in which real physicists strut and fret. Nobody really knows exactly what quantum processes in the real world would be responsible for weaving space-time’s fabric. Maybe some of the assumptions made in calculations so far will turn out to be faulty. But it could be that physics is on the brink of peering more deeply into nature’s foundations than ever before, into an existence containing previously unknown dimensions of space and time (or sight and sound) that might end up making The Twilight Zone into Reality TV.