Example Concept: Quantum error correction codes, such as the surface code and the Shor code, work by encoding logical qubits into a larger number of physical qubits. These codes detect and correct errors by using syndrome measurements that identify error patterns without collapsing the quantum state. For instance, the surface code arranges qubits on a 2D lattice and uses stabilizer measurements to detect errors, allowing for the correction of both bit-flip and phase-flip errors, which are common forms of decoherence.