The second quantum revolution

Quantum information and quantum technologies are at the forefront of the second quantum revolution. Quantum-enhanced applications will drive the technological progress in the 21st century and will play a similar role to that of electromagnetism and digital revolution in the last century.

The key idea of quantum information is to harness quantum effects (superposition, entanglement, non-locality, Heisenberg uncertainty, randomness) and to use them as a resource to perform tasks impossible in a classical world. In a nutshell, one can view quantum information as the art of manipulation and control of individual quantum systems in order to perform useful tasks.

By using quantum systems (photons, atoms, ions, electrons etc) as qubits (quantum bits), one can have an exponential increase in computational power for certain classes of problems. For example, a future quantum computer will be able to factor (and hence break present-day codes) in a matter of minutes; the same task would take the most powerful classical computer the age of the Universe.

Quantum superposition and quantum entanglement allow for secure communication guaranteed by the laws of physics. Quantum communication is pursued by many laboratories around the world. In August 2016 China sucesfully launched the first quantum communication satellite. This is a milestone towards a future quantum internet and will provide long-distance quantum communication.

Powerful quantum sensing and imaging devices will use entangled photons to achieve super-resolution and break classical limits. In this group are quantum telescopes, quantum microscopes, quantum interferometers and quantum radars.

In contrast to their classical counterpart, quantum simulators will be able to efficiently simulate quantum systems and their dynamics. Expected applications are a better understanding of molecular dynamics which will lead to novel drugs and materials, e.g., high-temperature superconductors.

Figure 1: A map of quantum information and quantum technologies

Quantum information is a multidisciplinary field and has connection to several disciplines, from information theory, nanotechnology and engineering to mathematics and philosophy. A map of the field is shown in Figure 1. The are broadly four main areas: (i) quantum communication; (ii) quantum imaging, metrology and sensing; (iii) quantum simulation and (iv) quantum computation.

The four areas have different degrees of technological maturity. Quantum communications and quantum sensing/imaging are the first, respectively second, generation of quantum technologies. Quantum simulation and quantum computation are less mature and are expected to take longer to implement.

Other active research areas are quantum control, quantum information theory, quantum entanglement and quantum foundations. Considerable effort is invested in finding suitable physical systems to implement quantum technologies. Implementations range from quantum photonics, ion traps, superconducting qubits, spins in quantum dots, nuclear spins in silicon etc. Developing quantum algorithms is another important field, with quantum machine learning becoming quite active recently.

 Quantum technologies worldwide

Research in quantum information has increased exponentially since the early ’90s. Several countries have strong research programs in quantum technologies, including Australia, Canada, China, EU, Japan, Singapore, US. UK has a €360 mil National Quantum Technologies Programme with four quantum hubs focused on key areas: networked quantum information (Oxford), quantum communication (York), quantum imaging (Glasgow), quantum sensing and metrology (Birmingham).

In May 2016 EU launched the €1 billion Quantum Technology Flagship. This was based on the Quantum Manifesto endorsed by more than 3500 people from academia and industry.

If a few years ago it was straightforward to list all the groups working in quantum information, nowadays this is almost impossible. Research groups, laboratories and whole institutes appear worldwide on a regular basis. A very short and incomplete list of large research institutes is: Centre for Quantum Computation and Communication Technology (Australia), Vienna Center for Quantum Science and Technology (Austria), Institute for Quantum Computing (Canada), Centre for Quantum Information and Quantum Control (Canada), QuTech (Netherlands), Centre for Quantum Technologies (Singapore), Quantum Science \& Technology Institute (UK), Institute for Quantum Information and Matter (USA), Joint Quantum Institute (USA).

The significance of the field can be assessed by looking at two parameters: the amount of funding and the number of patents.

Companies

Quantum technologies are a rapidly growing market. Many high-tech companies have R&D programs in quantum technologies: Toshiba (quantum communication), IBM and Google (superconducting qubits), Microsoft (quantum algorithms), Intel, NTT. IBM has recently launched IBM-Q, a cloud-based 16-qubit quantum processor and plans to expand it into a commercial platform. Other large organisations interested in quantum technologies are ESA and NASA.

The next table summarizes some of the companies operating in this field: