Sending the Most Bits Per Qubit
Once upon a time, I designed a variation of the superdense coding algorithm. The variation itself is beyond the scope of this article, but the key takeaway is that I used the textbook number of qubits — two — for the superdense coding part. I was already aware of a three-qubit implementation, and then I became aware of a five-qubit implementation. If using three is better than using two, than using five must be even better than using three, right?
The reason for this article is that you always see superdense coding demonstrated with two qubits, because that’s the easiest, simplest implementation. For that matter, teleportation is also always shown with two qubits. However, there are advantages to using teleportation with more than two qubits; are there advantages to using superdense coding with more than two qubits?
Introduction
The utility of textbook superdense coding is being able to transmit two classical bits via one transmitted qubit. This gives the sender a choice of 2² = 4 possible binary messages to send.
