‘I think I can safely say that no one understands quantum mechanics,’ said Nobel Prize winner Richard Feynman in 1965. Not to be discouraged: the famous scientist was referring to the fact that its rules are so different from those we have learned in contact with the macroscopic physical world that it is impossible to make them fit into our common sense. Even so, what this century-old science has shown is that it works and that it has changed our lives.

What is quantum science and technology? 

These disciplines are based on quantum physics, which deals with the study of matter at very small spatial scales. ‘Quantum theory explains nature on a microscopic scale and at very low temperatures, i.e. the behaviour of electrons, photons, etc.,’ David Pérez García, professor in the Department of Mathematical Analysis at the Complutense University of Madrid (UCM), describes to SMC España.

In the quantum world, ‘nature constructs a reality where particles and waves are one and the same thing,’ explains Perla Wahnón Benarroch, president of the Confederation of Spanish Scientific Societies (COSCE) and professor at the ETSIT of Telecommunications at the Polytechnic University of Madrid (UPM). Moreover, ‘it exists only with certain discrete energy states, quantized allowed states,’ says Wahnón.

How do quantum sciences and technologies differ from classical ones? 

As Pérez García explains, ‘the laws that govern these systems are very counter-intuitive from the perspective of the macroscopic phenomena at room temperature that we are used to’, which leads to the appearance of ‘very exotic effects’, explains the researcher.

These effects give rise to tremendous complexity in the quantum world, giving rise to phenomena such as superpositions, entanglement, superfluidity and superconductivity.

Quantum technologies, the main line of research of the professor at the Complutense University of Madrid (UCM), ‘aim to use these exotic effects to improve our technological capabilities,’ says Pérez García, such as ‘having more powerful computers, more secure communications, materials with better properties or more precise measurements.  In addition, the original postulates of quantum physics developed by John von Neumann in the early 1930s ‘are rich enough for new exotic quantum phenomena to continue to be discovered today,’ he adds.

What applications do quantum science and technology already have? 

Applications impact critical societal challenges such as medicine, climate, energy, food security and clean water, with technologies including ‘quantum chemistry, superconducting magnets, lasers, microprocessors, fibre optics, LEDs, new materials, supercomputers, magnetic resonance or electron microscopes,’ says the COSCE president. ‘It also explains many biological and physical energy phenomena,’ says Wahnón.

Quantum computers, which have more tools at their disposal to solve complex problems, are a new technological revolution. ‘The current race to build quantum computers can be considered the new space race,’ says Pérez García. ‘Prototypes exist, some with a moderate size of up to 100 units or cubits - quantum bits - but they are still imperfect devices,’ explains Diego Porras Torre, president of the Spanish Royal Society of Physics (RSEF) Quantum Information and Technology Specialist Group. ‘Large technology companies such as Google and IBM have experimental development programmes for quantum computers, and their potential is being studied in universities and research centres,’ he adds.

The current race to build quantum computers can be seen as the new space race

David Pérez García

Quantum computing provides solutions to the growing need for computational power, ‘especially in those applications in scientific computing, engineering or finance, which demand this capacity,’ says Porras. Quantum simulation uses controllable devices to recreate complex quantum systems and advance our understanding of the microscopic world,' says Porras.

The data encryption that will protect future economic and financial infrastructures will be more secure thanks to quantum communication, which, through cubits, ‘provides security in the transmission of information, for example, through the use of individual photons’, explains Porras.

Quantum metrology, with its ultra-precise measurement of time, ‘allows us to have better global positioning systems and a higher quality internet,’ says Humberto Michinel, professor at the University of Vigo, president of the European Optical Society and secretary general of the International Commission of Optics (ICO). It consists of ‘the use of quantum properties to make high-precision measurements, taking advantage of the sensitivity provided by atomic and photonic systems,’ says Porras.

In the medical industry, thanks to quantum simulations, ‘it will be possible to develop personalised medicines more quickly or to better understand complex systems such as the human genome or the climate,’ says Michinel. For example, photonics promises advances in medical imaging and diagnostics. In addition, quantum chemistry is supporting the development of new vaccines and drugs.

In the logistics and transport industry, these technologies will enable ‘the design of more efficient routes or optimised energy networks, which can be better solved thanks to quantum algorithms, improving the management of countless resources,’ says Michinel.

In conclusion, ‘in the long term, these technologies will redefine entire industries, improve the quality of life and offer solutions to global problems, such as energy sustainability or understanding climate change. They will also generate new jobs that will require advanced training for new generations of technologists,’ says Michinel.

How does their evolution affect us? 

Quantum science describes the physical world and ‘responds to the human desire to understand it’, says Pérez García. Claiming the importance of the development of quantum technologies ‘means betting on advances that drive innovation in key technological sectors such as medicine, cybersecurity, new energy sources or artificial intelligence, among other fields,’ explains Michinel. ‘These technologies are essential to build a more sustainable, secure, innovative and prosperous future.

Being aware of advances in these sciences allows societies to ‘better understand the changes that these technologies bring, ensuring that knowledge and benefits are distributed equitably and that new capabilities are used ethically and responsibly,’ says Michinel. ‘It also encourages investment in education and the creation of future high-quality jobs,’ he adds.

The general public is often given a distorted view of quantum science, which is presented as an exotic theory or even connected to pseudo-scientific practices

Diego Porras

‘The general public often receives a distorted view of quantum science, which is presented as an exotic theory or even connected to pseudoscientific practices,’ says Porras. For this reason, he says, ‘it is necessary to disseminate quantum physics and explain that it is based on theories that only directly affect the microscopic world, but that have been proven with great precision and are the basis of other disciplines or even applications such as lasers and electronics. It is very likely that many new applications of quantum science have yet to be discovered,’ concludes the researcher.

What can we expect from the celebration of 2025 as the International Year of Quantum Science and Technology?

‘For a country like Spain, which has a high-quality university and scientific training and research system, this celebration is an opportunity to show society an increase in investment in a field that will generate enormous economic benefits in the future,’ says Michinel.

Researcher Diego Porras points out that the RSEF's Quantum Technologies and Information Specialised Group is preparing a website for this celebration, which will be updated with material and activities related to it. He also mentions TalentQ as a useful resource, as part of the Quantum Spain project, which focuses on quantum computing.