NPL envisages that appropriate metrological techniques and standards will be required to support the development of markets based on quantum information technologies. Furthermore, it is anticipated that quantum entanglement will play a significant role in precision measurements of the future.

Quantum technologies offer the prospect of processing and communicating information in fundamentally new ways. This is made possible by the defining features of quantum mechanics; i.e. the weird and wonderful phenomena of superpositions and entanglement, together with the no-cloning theorem.

Two-state quantum systems can be used to represent bits of information, similar to the ones and zeros of a classical system. A quantum system may be prepared in a superposition of the two states, and so can be in both states at a given moment in time. This unique feature has no analogue in a classical information system. The ability to prepare a quantum bit ('qubit') in a superposition state enables a variety of novel algorithms not possible in classical information theory.

Two or more of these quantum systems can be brought together and entangled; entanglement describes correlations between quantum systems that are much stronger than classical systems. Entanglement is a crucial resource in realising any of the elementary building blocks of a quantum processor. Moreover, entanglement is a phenomenon that offers enhancements in precision measurements, when compared to a classical system.

Trapped ions, neutral atoms, photons, superconducting devices, and solid-state systems are all cited as potential candidate systems for creating a quantum processor. Laboratory demonstrations of specific quantum logic gates and algorithms have been made, however a truly useful quantum processor is some considerable way off. Nevertheless, the potential gains are significant and disruptive, hence the current level of worldwide research in this topic.

Much closer to market is quantum key distribution; a technology that enables the secure transmission of cryptographic keys. Bits of a key are encoded into single photons, which are transmitted over an optical fibre to a receiver. The ability to detect the activities of an eavesdropper is guaranteed by the laws of quantum mechanics. This has obvious advantages for the secure transmission of data in markets as diverse as defence and finance.