Quantum mechanics is a branch of physics invented at the beginning of the 20th Century.  What exactly its complex equations mean is still in dispute, but what we know is that it is capable of more accurate predictions than any physical theory before it.  Since the 1980s or so, entrepreneurs and technologists have translated the insights of quantum mechanics into new, revenue-generating quantum technologies.

Quantum computing: Quantum mechanics provides a physical platform for a new kind of computing that enables problems to be solved that cannot be solved in any reasonable period of time.  Quantum computing presents new business possibilities in financial services, healthcare, pharma and many other areas.

Quantum key distribution and the Quantum Internet: Quantum computing also potentially creates some big problems, most especially that when quantum computers become a little more powerful, they will be able to break common encryption schemes – the ones that are currently used to protect e-commerce and bitcoin, for example. This problem is spawning new businesses and technologies.

The most immediate solution is post-quantum cryptography (PQC) which is an attempt to come up with new encryption schema that cannot easily be broken with a quantum computer.  Alternatively, Quantum key distribution (QKD) uses the laws of quantum physics to ensure that it is physically impossible for an interloper to steal the encryption keys from an encrypted link.

There is already much talk of building networks using QKD and how these will evolve into a Quantum Internet.  However, to make long-haul quantum networks happen will take the development of quantum repeaters – the equivalent of an optical amplifier in an optical network.  Quantum repeaters are receiving growing attention from the research community, and it is reasonable to expect commercial quantum repeaters to emerge in less than five years.

Quantum sensors: Finally, quantum sensors.  These are sensors that make use of the extreme sensitivity of quantum systems and can therefore improve on the performance of classical sensors.  Some kinds of quantum sensors have existed for years, but researchers are seeing their use expand rapidly in areas as disparate as medical imaging and oil exploration.