Quantum technologies encompass a wide class of devices — for information processing, communication, sensing, and simulation — which work, at their core, by exploiting quantum effects. Which type of quantum effects and why is this even possible or desirable? These are good questions at the very heart of the definition of quantum technologies.

Some concepts of Quantum Physics have already provided us with devices for everyday use. This is the case, for instance, with the transistors inside our computers and telephones, the lasers in bar code readers or the MRI systems used worldwide to diagnose patients. These existing and widespread technologies would not have been invented without the discovery of the laws of quantum physics, such as the quantisation of energy and the quantum coherence of light.

However, when we talk about quantum technologies today, we are referring to something rather different and, indeed, much more “radical”. The advent of a new technological era could be just around the corner, with the development and deployment of new devices thanks to advances in scientific and technological research, in particular the amazing ability to detect and manipulate individual quantum objects.

To understand how quantum technologies work, we must emphasise that they are not simply more precise, faster or safer. Their way of solving current problems is based on a completely different "logic”. In fact, quantum systems behave according to quantum mechanics, making use of ingredients that are not available in our current devices. Therefore, to develop a quantum device, for example a quantum computer, it is not enough to build quantum hardware, but it is also essential to create completely new software, as software running on conventional computers cannot simply be adapted.

In general, quantum information is the discipline that studies how information is processed, stored and transmitted using quantum phenomena. When we encode information in quantum systems, which can exhibit quantum properties such as superposition or quantum entanglement, this information can be processed differently than by classical means. This allows us to obtain results that go beyond those obtainable with classical information processing. Some of the applications of quantum information are: quantum computers and simulators (used to process information), quantum communication (used to transmit information securely) and quantum sensing (used to retrieve information accurately). These are the quantum 2.0 technologies to which we aspire today.

Quantum computers, in particular, are the most eagerly awaited. The reason is that they promise to solve problems intractable with traditional computers, thus making the impossible possible. For instance, quantum computers are expected to profoundly influence pharmacology, robotics, cryptography, data science, artificial intelligence and virtually any field that relies on computing power. Moreover, they could enable us to find solutions to the great challenges of our society, from healthcare to energy and the environment. In this sense, they will hopefully lead us to a new, better and more sustainable world.