Quantum mechanics is the physics theory describing the laws of nature at the particle level. It emerged in the early 20th century and has since developed into a vital part of the technology sphere, associated with important, often perplexing phenomena. These include a system’s ability to simultaneously exist in multiple states (superposition), or to exhibit connection between particles despite large physical separation (entanglement).
Many widespread technologies such as transistors, lasers, and magnetic resonance imaging make use of properties deriving from the laws of quantum mechanics or must consider them in their design. While quantum mechanics is already embedded into existing Information and Communications Technologies (ICT), the potential of quantum resources is far greater.
Over 100 years have passed since the advent of quantum theory. This year, we celebrate the centennial of Einstein’s 1921 Nobel Prize for describing the photoelectric effect, a key milestone in its development. Systems capable of controlling and harnessing quantum resources have significantly matured since Einstein’s time. Similarly, advances in quantum theory have granted vision for non-classical applications in fields as diverse as communications, information processing, simulation, and sensing. Researchers have also made significant progress in experimental platforms such as quantum photonics, superconducting systems, and trapped ions.
As quantum information science (QIS) has matured, ICT leaders’ reactions range from disinterest to excitement. Some researchers dismiss quantum computing as a one-trick pony that will destroy our current security infrastructure by hacking into public-key cryptography. Others believe that QIS will provide the solution to nearly every problem in ICT, including a path to faster-than-light communications or the answer to managing big data.
In reality, the promise of QIS lands in the middle: it has wider potential applications than some assume, but its powers are not limitless. We do not yet know what a large-scale error-corrected quantum computer capable of breaking encryption will look like, and QIS cannot violate relativity or solve all our data problems.
The future of quantum technology, though, is bright. Quantum sensing is enabling lower noise floors than possible in any classical system, which has already improved gravitational wave detection. Quantum simulations—in which controllable quantum systems are used to study others—are advancing rapidly and could provide new scientific insights with much smaller resources than needed for error-corrected quantum computing.
In this sense, quantum information is here to stay because quantum mechanics is here to stay: the complexity of quantum systems is such that only truly quantum resources are capable of encoding and exemplifying their basic features. In the coming years, we therefore predict more measured expectations for QIS, but also a steady growth of application areas, as controllable quantum resources are increasingly put to work not just for information processing, but also fundamental science.
These advancements have spurred interest in quantum research beyond the confines of academia, as start-ups and industrial giants pursue applications for this technology, attracting hundreds of millions of dollars worldwide in federal and private investment. Key achievements include Google’s 2019 demonstration of “quantum supremacy” (using a programmable quantum system to solve a computational problem faster than known non-classical methods); just two months ago, the academic group of Jian-Wei Pan published a second report of quantum supremacy, this time using a photon-based system.
Investment and development of quantum technologies will continue, and we should be prepared to witness further milestones in the near-term.
