There may be a layer of reality even deeper than the quantum realm Cappan/iStockphoto/Getty Images Physicists are making new inroads into the world of post-quantum theories, uncovering what reality may look like on a level deeper and stranger than the already infamously odd quantum theory. In the 1920s, physicists had several extremely useful theories for how the world works, yet they kept uncovering situations where those theories didn’t work. Through these holes in so-called classical physics, they glimpsed a deeper layer of the world that underlies everything – the quantum realm. Now, physicists are having déjà vu. Quantum theory works incredibly well, but it also has gaping holes when confronted with cosmically large objects controlled by gravity. What sort of post-quantum world could reveal itself through that hole? James Hefford at the National Institute for Research in Digital Science and Technology and Matt Wilson at Paris-Saclay University, both in France, have now developed a mathematical sketch of one plausible post-quantum world, possibly the deepest layer of reality yet. “Quantum theory doesn’t describe the entire universe,” …