(August 10, 2016 at 4:06 am)Alex K Wrote: According to what we currently know about the laws of physics, there doesn't seem to be a feasible way to break the speed-of-light barrier.
Quantum Entanglement - if you look at how causality plays out in Quantum Field Theory (that's currently the best experimentally secured description of quantum physics which also takes into account relativity), yes, there's this spooky action at a distance thing. But if you write down the mathematical formula for a communication at superluminal speeds, you find that the spooky particles and the spooky antiparticles exactly cancel each other out and you get zero; It's a famous textbook example, it's in my book as well - nature makes sure that no information can be transported until enough time has passed - as soon as enough time has elapsed, the quantum formula returns a number different from zero and communication is possible. It's the strangest thing, as if the universe had built-in machinery set up to hide superluminal messages from us.
Our only hope would be messing with space-time itself in order to shorten the path to the remote point by changing the geometry or topology of space. If you'd have a (as far as we know inexistent) substance with negative Energy, that would upset the maths of the above calculation, and information could travel faster than light (the recently often-discussed example is the Alcubierre Drive). But my personal opinion from what I've seen is that as soon as this kind of device would actually work, one would unavoidably run into time travel paradoxes. If wormholes in spacetime, connecting distant reaches via a shortcut, would exist, that would work, but it's not clear whether they can be stable and traversible without erasing everything that tries to pass them. So far, we haven't seen one. To make wormholes, one would probably again need this weird negative energy substance to keep them stable.
So my conclusion so far is that it's not completely out of the question that it might one day be feasible if some surprising physics discoveries happen, but so far, not much speaks in favour of the possibility.
Which paradoxes are we talking about here, and what would some possible solutions?
