Questions of whether our reality is a simulation of something deeper have kept philosophers and freshmen awake since Plato was a pup.
A pair of physicists sleep a lot easier at night now that they’ve shown that quantum weirdness involving twists in space-time can’t conceivably be simulated, adding to a list of problems that The Matrix would have no answer for. Sorry Neo.
Theoretical physicists Zohar Ringel and Dmitry Kovrizhin from the University of Oxford and the Hebrew University in Israel found a solid road-block to solving algorithms involving quantum-based Monte Carlo simulations.
The short version is, it basically means we can’t model the physics we know of on even the biggest computer imaginable.
You’re not in a simulation. Probably not, at least.
Still with us? Ok, come on down.
Monte Carlo simulations are computations based on random samples of a system. They’re not particular to quantum physics, but they are useful for turning the fuzzy world of maybes into something a bit more predictable.
For the most part they can help make short work of certain many-body problems – systems involving multiple quantum objects moving about through various dimensions.
Quantum Monte Carlo simulations are by no means perfect, though. A certain cancelling out of positives and negatives can arise, something referred to as a sign problem.
Sign-free representation would help get around it, but the way to do this for a lot of physics problems remains unclear. In fact, for some it might be downright impossible.
That’s the question Ringel and Kovrizhin were tackling; is there some sort of barrier to finding a sign-free way of applying Monte Carlo simulations to certain quantum systems?
If there isn’t, then maybe – just maybe – you’re lying bathed in gel in a pod somewhere with tubes in your head while a giant computer milks you for electricity in the world’s most inefficient battery.
But should there be an obstacle, it means classical computers could never solve the…