Video: Quantum Gravity Breaks Causality -- And You Can Compute With It
Transcript 0:00 Flip the switch and the light turns on. “Duh,” you might say. Physicists say “causality”. Lights 0:06 don’t turn on by themselves and then make switches flip. And that sounds all well and 0:12 fine except. Quantum physics screws it up. In quantum physics, lights can turn on and 0:19 make switches flip, in some sense. And as if that wasn’t crazy enough, 0:23 some physicists now say you can actually use that to build better computers. Let’s have a look. 0:30 Quantum particles can be in two places at once. We call this a “superposition” of two 0:35 places. That’s definitely weird, but it gets weirder. The maths of quantum mechanics says 0:41 that this shouldn’t just be the case for small particles. In principle, it could happen for 0:46 anything, molecules, bananas, cats. This is why Schrödinger was going on 0:51 about a dead-and-alive ca...