Quantum mechanics describes systems at the molecular distance scale and below, where ideas such as uncertainty principles, superposition and entanglement are required to describe the dynamics. It explains the macroscopic behaviour of solids and the chemical elements as a consequence of interactions on the quantum scale. Many technologies rely on quantum mechanics such as: solar cells, lasers, magnetic resonance imaging scans (MRI) and batteries.
In order to solve ever more complicated problems, quantum computers have been developed that are based on quantum mechanics and they use complex qubits rather than than the binary 1 and 0s used in classical computers. Quantum computers can solve some problems exponentially faster than existing classical computers. Examples of the applications that quantum computing are expected to be useful for include: drug design, logistics and cryptography. Once esoteric ideas in quantum mechanics such as "spooky action at a distance" are now useful in distributing keys in cryptography.
Currently existing quantum computers are small and they face practical problems from decoherence and quantum noise. Industry and the government are investing billions of pounds to create larger quantum computers and they require a quantum enabled work force to develop the vast economic potential of quantum computers.
