Quantum technology is an emerging field of physics and engineering, which relies on the principles of quantum physics. It is about creating practical applications – such as quantum computing, quantum sensors, quantum cryptography, quantum simulation, quantum metrology or quantum imaging – based on properties of quantum mechanics, especially quantum entanglement, quantum superposition and quantum tunnelling.
Over the past 20 years, quantum technologies have made great strides: they have evolved from laboratory experiments to a multi-disciplinary field of research and development in science and engineering. In particular, the last five years have seen a tremendous acceleration driven by advances in quantum computing and the potential it can offer in the acceleration of complex computing problems.
Today, quantum technology is organised into four main domains of R&D and applications:
- Quantum computing and algorithms: Quantum effects, such as superposition and entanglement, are used to speed up certain classes of computational problems beyond the limits achievable with classical systems based on logical bits. The range of issues that can potentially be accelerated goes from optimisation or simulation to sophisticated machine and deep-learning applications.
- Quantum simulation and information processing: Applications to QCD1 (Quantum Chromo Dynamics), non-perturbative dynamics using lattice QFT and more, map of quantum field theories onto quantum devices, use of well-controlled quantum systems to simulate or reproduce the behaviour of less accessible many-body quantum phenomena, noise and error control by investigations of Hilbert-space truncation mitigations.
- Quantum sensing, metrology and materials: The high sensitivity of coherent quantum systems is used to design new classes of sensors. Detectors ranging from instruments measuring local nanoscale information to devices relying on planetary-scale coherence can significantly improve precision and enable new measurement protocols.
- Quantum communication and networks: Single or entangled photons and their quantum states are used to implement provably secure communication protocols across fibre-optic networks or quantum memory devices able to store quantum states.
Besides these four main domains of R&D, cross-cutting areas are emerging that bring together elements of more than one domain, potentially supporting a wide range of scientific and technological applications. For example, quantum software and algorithms – or a combination of quantum sensors, network software and communication protocols – can be brought together to create potentially precise, large-scale detector systems.