An Easy-to-Follow Lesson On Superdense Coding

Learn about Superdense Coding, a fascinating technique that makes it possible to send two classical bits of information using only one qubit.

6 min readSep 29, 2025

Superdense coding is a fascinating quantum communication protocol.

It involves transmitting two classical bits of information using only one qubit.

This is very different from classical computing, where if you want to send 2 bits of information, you will need to transmit 2 bits through a channel.

Bell states are used extensively in Superdense coding.

These are maximally entangled two-qubit quantum states, and we have already discussed them in detail in the last few lessons on Into Quantum.

If you missed out on these posts, here are the links to them:

Let’s now begin with understanding Superdense coding!

Consider Alice, who wants to send 2 bits of information to Bob using a single qubit.