A New Quantum Paradox Flags Errors in Our View of Reality

That quantum mechanics is a successful theory is not in dispute. It makes astonishingly accurate predictions about the nature of the world at microscopic scales. What has been in dispute for nearly a century is just what it’s telling us about what exists, what is real. There are myriad interpretations that offer their own take on the question, each requiring us to buy into certain as-yet-unverified claims—hence assumptions—about the nature of reality.

Now, a new thought experiment is confronting these assumptions head-on and shaking the foundations of quantum physics. The experiment is decidedly strange. For example, it requires making measurements that can erase any memory of an event that was just observed. While this isn’t possible with humans, quantum computers could be used to carry out this weird experiment and potentially discriminate between the different interpretations of quantum physics.

“Every now and then you get a paper which gets everybody thinking and discussing, and this is one of those cases,” said Matthew Leifer, a quantum physicist at Chapman University in Orange, California. “[This] is a thought experiment which is going to be added to the canon of weird things we think about in quantum foundations.”