Key Issue: What is quantum communication ?
Quantum communication is a field that leverages the principles of quantum mechanics - particularly superposition, entanglement, and the no-cloning theorem - to enable secure information exchange between distant locations. Quantum networks facilitate the transmission of quantum bits (qubits) between physically separated quantum processors, forming an essential element of quantum computing and communication systems. A key application is quantum cryptography, which provides inherently secure communication because any attempt to intercept or eavesdrop on a quantum communication will necessarily disturb the quantum state in a detectable way. Quantum Key Distribution (QKD) is one of the most developed applications, allowing parties to generate secure encryption keys that cannot be intercepted without detection. The technology can work through optical fiber cables or free space, though current fiber-based systems are limited to distances around 200 kilometers without quantum repeaters. IBM plans to incorporate quantum communication capabilities into their quantum computing systems by 2026, enabling quantum processors to communicate with each other through quantum links. The emerging quantum internet will support functionalities with no direct counterpart in the classical world by enabling quantum communications among remote quantum nodes. Researchers are actively working on developing quantum repeaters, improved photonic chips, and satellite-based systems to extend the range and reliability of quantum communication networks.