Abstract
Quantum mechanics has been the driving force behind the major technological revolutions of the second half of the 20th century, lying at the heart of, amongst other things, the transistor, the laser and navigation systems. Yet these innovations have not made use of the most subtle concepts – those that were the subject of so much debate amongst the founders of quantum mechanics: quantum superposition and entanglement. These concepts, which still defy our intuitions today, pave the way for new ways of encoding and manipulating information. Observing and exploiting them, however, requires an unprecedented degree of control over physical systems.
Decades of research in quantum physics, applied to a wide variety of systems – ranging from light to semiconductor and superconducting components, via atoms – have gradually made it possible to manipulate highly ‘pure’ elementary quantum systems, and to demonstrate, and subsequently master, quantum superposition and entanglement. It is now possible to generate light photon by photon, to synthesise artificial matter atom by atom, to sculpt artificial atoms using microelectronic tools, and to entangle photons and natural or artificial atoms.
These scientific advances are now making it possible to develop the first applications that utilise entanglement and superposition. These include, in particular, the development of quantum processors capable of performing calculations beyond the reach of current supercomputers, the implementation of communication protocols secured by the fundamental laws of quantum mechanics, and the development of ultra-sensitive sensors, facilitating, for example, the detection of gravitational waves. The applications are numerous, spanning fields linked to digital sovereignty, whilst also promising new scientific discoveries.
We shall endeavour to describe the early stages of this adventure, in which fundamental research and technological developments are advancing resolutely hand in hand. It is a rapidly expanding field at international level, where a certain poetry and aesthetic blend on a daily basis with extreme scientific ambitions and intense competition, commensurate with the stakes involved.
Pascale Senellart’s lectures are taking place as part of the International Year of Quantum Science and Technology , which in 2025 marks the 100th anniversary of the discovery of quantum physics.
