Time Travel Simulation Shows Quantum 'Butterfly Effect' Doesn't Exist
Here's the story – our protagonist rewinds history, locates baby Hitler, and averts global war by putting him on a path to peace … but, oh noes! This sets off a domino chain of events that stops our hero from being born, or worse, kicks off the apocalypse.
Unintended 'butterfly effect'-style consequences of time travel might be a juicy problem in science fiction, but physicists now have reason to believe in a quantum landscape, tweaking history in this way shouldn't be a major problem.
Since going back to a previous moment in time is still in the 'too hard' basket, a pair of physicists from the Los Alamos National Laboratory in the US went with the next best thing and created a simulation using an IBM-Q quantum computer.
"On a quantum computer, there is no problem simulating opposite-in-time evolution, or simulating running a process backwards into the past," says theoretical physicist Nikolai Sinitsyn.
It's hardly as complex as a Universe of human actors and historical events, but a small stage made up of correlated quantum states is plenty for researchers to replay events with tiny changes to see how things play out.
"So we can actually see what happens with a complex quantum world if we travel back in time, add small damage, and return. We found that our world survives, which means there's no butterfly effect in quantum mechanics," says Sinitsyn. ...