Entanglement is the feature of quantum mechanics that has no classical counterpart, and it is a key resource behind many quantum algorithms and protocols. This module explains what entanglement is and then shows what it makes possible, using the gates and states from earlier modules.
It starts with a plain-language explanation of entanglement and why it is so unusual. From there it covers how to prepare a Bell state with a Hadamard and a CNOT gate, and then puts entangled states to work in superdense coding (sending two classical bits with one qubit) and quantum teleportation (transferring an unknown quantum state using entanglement and classical communication).
The last three lessons come from a short series that builds step by step, so watch them in order. Then continue on to Quantum Programming with Qiskit.
An accessible introduction to what entanglement is, why Einstein found it so strange, and how it is starting to be used in technology.
Michael Nielsen shows how a Hadamard gate followed by a CNOT gate turns two qubits into an entangled Bell state.
Michael Nielsen's introduction to the superdense coding protocol, which uses a shared entangled pair to send two classical bits per qubit.
Michael Nielsen walks through the teleportation protocol step by step: how an unknown qubit state is transferred using entanglement and two classical bits.