Example Concept: In quantum communication, entangled qubits can be used to detect errors through entanglement-based error correction protocols. When qubits are entangled, any disturbance or error affecting one qubit can be detected by observing changes in the entangled partner, allowing for error correction without directly measuring the qubits. This principle is foundational in quantum error correction codes and QKD, where entanglement ensures that any eavesdropping attempt alters the state, thus revealing the presence of an intruder.