Our quantum world has many odd and counter-intuitive features. One of these is “tunneling” — the ability of objects to pass through walls, escape from traps, and slip under mountains into the next valley. We don’t encounter this effect in daily life; objects we’re used to are so incredibly unlikely to tunnel from one place to another that we will never hear of one doing the apparently impossible. But in the atomic and subatomic realms, even in various types of modern technology, tunneling is an essential and commonplace feature of the quantum reality in which we live.
I’ve written a short article about this phenomenon, which you can read here, emphasizing the central role that tunneling plays in the world’s most powerful microscopes. It should be suitable for anyone who has read a little about atoms.
This article lays the groundwork for a discussion of how tunneling could someday, in the distant future, end the universe as we know it. It also prepares the way for a more advanced post about how a single physics theory (i.e., a set of equations designed to describe some aspect of nature) may have multiple `vacua’ (i.e. multiple solutions that each represent different ways that the universe could be configured — what empty space could be like, and what types of fields, forces and particles could be found in the universe — over long periods of time.) If that’s confusing, stay tuned for a few days; I’ll soon explain it.