The quantum breakthroughs set to shape 2025
By Isabella Castel-Branco
Last June, the United Nations General Assembly proclaimed 2025 as the International Year of Quantum Science and Technology (IYQ) to mark the centenary of the birth of the “new quantum theory”. The initiative aims to internationally recognise the importance of quantum science today by celebrating its past contributions and raising awareness for its future applications. Quantum science ideas have already made their way into general culture – such as Schrödinger’s cat thought experiment or Einstein’s statement that “[God] does not play dice” – but IYQ aims for more by encouraging the achievement of sustainable development goals in all aspects of life, through quantum science.
Quantum sciences is a term encapsulating all branches of science that apply to particles, which are the various building blocks of energy and matter. Quantum physics, quantum chemistry, quantum information and more – all study and exploit the intrinsic properties of the particle realm.
In accordance with the scientific method, inconsistency between theory and experiment stems either from a faulty initial hypothesis or an error/unknown in the experimental procedure or configuration. In 1900, German physicist Max Planck investigated what was known as the “Ultraviolet Catastrophe”: a theoretical prediction which yielded completely inaccurate results. Planck bypassed the issue by assuming that radiated energy was made of discrete, quantised packets he called “quanta” instead of a continuous flow (as assumed until then). His new equation produced results which corresponded to experimental measurements. In fact, what he thought was an unphysical mathematical trick was instead the foundation of quantum mechanics. This break with former physics (dubbed classical physics) unleashed a snowball of discoveries concerning particles, energy and their intersection – since the physics developed until then did not apply to particles, new “quantum” rules had to be formulated.
The present understanding of quantum phenomena is expected and encouraged to be implemented across all fields, and indeed, various sectors are gravitating towards quantum technology
Whilst the development of quantum physics began at the dawn of the 20th century, the critical turning point is widely considered as 1925. In the first period (1900-1925), pioneers created hypotheses and models by finding analogical systems in classical mechanics and adding new rules, forming “old quantum theory”. The most known is the Bohr model: the atom’s nucleus, consisting of protons and neutrons, is orbited by electrons (as we were taught in school!). Whilst refinements were made, and it was successful in describing non-classical phenomena for the first time, constrictions allowing theory to fit experiment were added on without rigour; these models were therefore unsuccessful in predicting the behaviour of more elaborate and complex quantum systems.
In 1925, three physicists, W Heisenberg, M Born and P Jordan, published a collaborative flurry of papers introducing a new mathematical language to physics to describe quantum phenomena. Similarly, in 1926, E Schrödinger produced equivalent mathematical formalism by describing particles as waves. Heisenberg’s Matrix Mechanics and Schrödinger’s Wave Equation were the foundations of “quantum mechanics”, the framework and rules which describe particle behaviour. From then on, the nascent field developed rapidly. P Dirac, another founding father of quantum mechanics, remarked: “It was very easy in those days for any second-rate physicist to do first-rate work”.
One of the greatest expectations of the quantum theory was the correspondence principle: at large scales, quantum mechanics yields classical mechanics. A large collection of particles constitutes matter as we know it since a ball, a bullet and a bob all amount to the agglomeration of many quantum systems. This principle holds true: in fact, it is possible to derive Newton’s second law from the principles of particle behaviour.
The applications of quantum knowledge have since grown vast. The most mediatised so far is quantum technology, with quantum information and quantum computers in particular. Since electronic components have reached atomic scales, quantum properties have been exploited to exponentially increase computing power and, hence, decrease computing time by manipulating individual particles instead of current bits.
The use of quantum knowledge in medical imaging, for instance, is directly relevant to IYQ goals
Whilst lesser known, the use of quantum knowledge in medical imaging, for instance, is directly relevant to IYQ goals: it is expected that MRI image reconstruction and processing could be accelerated and that diagnostic insights could be suggested through quantum computing coupled to machine learning. Similarly, quantum chemistry could quicken the development of new vaccines and treatments thanks to a more accurate understanding of complex molecular interactions. For instance, most recently, in 2024, IBM’s quantum computers were used to predict the most appropriate antibiotic treatment for patients with UTIs during the waiting period for their urine test results – the machines then outperformed the physicians.
The present understanding of quantum phenomena is expected and encouraged to be implemented across all fields, and indeed, various sectors are gravitating towards quantum technology. Thanks to its power, its potential is vast and malleable. Knowing this, the UN’s initiative aims to provide all with the relevant educational background to understand and be capable of following the future.
Image: Pierre Metivier via Flickr
