While teaching my future 6th grader about how quantum tunneling enables positively-charged hydrogen nucleii to overcome like-charge repulsion so that nuclear fusion may occur in the Sun, my student first made a joke about the hydrogen nucleii teleporting. I replied that quantum teleportation is a very real thing, but that it would be a lesson for another day. It’s also not what anyone would expect it to be.
The word "teleportation," of course, conjures up images of Star Trek transporters beaming crew members to and from planets, ships, and other adventurous places. Point one is that actual teleportation moves neither matter nor energy; it only moves information.
I’ve been using two younger siblings as props, but this lesson required adding myself as a third prop. Building on our lessons on superposition and entanglement, we first placed the two sibling-electrons under two bedsheets to become entangled. One sibling-electron stayed in place under one bedsheet, while the other sibling-electron took the second bedsheet and moved to the other side of the room.
I represented the third electron, the one with the information that we want to send. I moved under the first bedsheet to become entangled with the first sibling-electron.
I initially gave an extremely oversimplified explanation of what happens: my information passes through the first sibling-electron to the second sibling-electron. The first sibling-electron can be thought of as never really knowing what the information was, and daddy is so old that I immediately forgot what the information was. In the end, only the second sibling-electron has the information. The information has therefore been moved, not copied.
My student understood that quite easily, so I reduced the oversimplification. When I became entangled with the first sibling-electron, I shared some of my information. I immediately forgot the information that I shared, but I remembered the rest of it. The first sibling-electron and I had to send each of our pieces of information to the second sibling-electron in order for the information to make sense on the receiving end.
This analogy, while imperfect, maintains that the archetypical Alice and Bob at least have the required unknown quantum state along with two classical channels. It also makes clear that only information is being transmitted.
The logical progression of this lesson series is superdense coding, so that is tentatively next. However, true to reality, adding sophistication makes controlling young sibling-electrons more and more challenging.