Example Concept: Quantum error correction involves encoding logical qubits into a larger number of physical qubits using codes such as the surface code or the Shor code. The surface code, for instance, requires a 2D lattice of qubits where each logical qubit is protected by a grid of physical qubits. The number of physical qubits needed scales polynomially with the desired error rate and fault tolerance level, meaning that as you increase the number of logical qubits, the overhead in physical qubits and the complexity of the error correction circuits increase significantly.