The principles underlying quantum technologies are well established, and have been brought to life in academic and industrial laboratories, says Prof Dmitry Krizhanovskii and Prof Pieter Kok

Since the late 20th century, our world has been powered by what computer scientists call classical computing. It’s the world of ones and zeroes that governs desktop PCs, mobile phone calls and DVD players.

But in recent years, the focus of researchers working at the cutting edge of computing has shifted. We have started to enter the quantum age. Whereas classical computer and communication systems use binary code to process information as either a one or a zero, a quantum computer operates with so-called quantum bits (or qubits) which take ones or zeroes at the same time with a certain probability. The ability of quantum computers to process ones and zeroes at the same time leads to novel types of functionalities, enabling systems to tackle very complex problems that would take even a modern classical supercomputer millions of years to solve.

Up to now scientists have been developing a variety of physical systems representing qubits, including superconducting Josephson junctions, single atoms, ions and electrons, to name just a few. The development of nanophotonic technology enabling an efficient generation, manipulation and detection of single light particles (photons) using advanced semiconductor nanostructures or 2D materials has opened the door for quantum optical applications. Nowadays, photonic qubits are considered to be one of the most prominent systems for development of quantum computation, communications, metrology and imaging.

These innovations have brought scientists to the brink of the next digital revolution. Technology companies of all kinds — from plucky start-ups to some of the world’s biggest corporations — are investing in quantum science to bring consumers devices that are smaller, faster, more powerful, more efficient and more secure.

The principles underlying quantum technologies are well established, and have been brought to life in academic and industrial laboratories. But there are still questions that will need to be addressed before we can all carry quantum devices in our pockets.

How to build an ideal single-photon source that can produce the required identical light particles at a very high repetition rate that quantum technologies rely on? How can we build a quantum communication system that can carry information over thousands of miles? What is the optimum architecture of a quantum photonic computer and can it be built using purely interfering (non-interacting) photons or an introduction of photon-photon interaction through nonlinear optical materials is required? Which devices will get the biggest boost by being upgraded from classical to quantum computer systems?

The scientists that help answer these questions will play a major role in the future of technology. As a result, more and more career opportunities for graduates of quantum-related degrees are emerging. Global brands such as Amazon, IBM, Google, Microsoft, Hitachi and Toshiba all have teams of engineers working in quantum computing or communication. As the industry grows, these teams will need to grow too. Science and engineering graduates who understand this complex field will be essential to plug the gaps that open up when companies join the quantum revolution.

MSc courses on Quantum Photonics and Nanomaterials teach students about aspects of quantum physics that are paving the way for quantum technologies. Students will study the fundamental properties of light and matter, and how they interact with each other. This includes learning how semiconductors are used in electronic and optoelectronic devices, ranging from nanophotonic circuits, and micro- and nano-sources of quantum light, to photovoltaic solar cells.

In the next few years, many more start-ups will join the quantum race, and more established companies will expand their quantum operations. Now that the route to a quantum future is being marked out, it's the perfect time for science students to take a place on the starting line.

The writers are from Department of Physics and Astronomy, University of Sheffield, UK