As the Quantum Year comes to a close the debate on the development of these technologies has assumed unprecedented significance. What for decades was the subject of theory and abstract models is beginning to materialize in real systems, such as the IBM–Basque Country quantum computer, up and running in Donostia / San Sebastian in the Ikerbasque building in the heart of the quantum mile, just a few metres from the nanoGUNE headquarters. This advance represents a significant milestone, but it also carries a huge responsibility: the path towards applications capable of addressing the major challenges it promises has yet to be built.

One of the most significant challenges lies in bridging the gap between two realms: the classical and the quantum, in the field of computing. For decades, science, and materials science in particular, has resorted to “classical” computers to simulate nature. These methods have made it possible to explain a myriad of phenomena, particularly in atomistic systems. While more straightforward calculations are done on conventional computers, more complex ones require HPC (High Performance Computing) supercomputers, such as those available at the EHU-University of the Basque Country or the Donostia International Physics Center (DIPC).

These simulations use specialized codes such as SIESTA, which is employed by several thousand researchers worldwide and by technology companies for advanced simulations. “SIESTA is a program that allows us to ‘see’ how atoms and molecules behave without the need for actual laboratory experiments. It is software used to simulate the electronic and structural properties of materials, from biological molecules to complex solids,” explained Emilio Artacho, an Ikerbasque Research Professor at nanoGUNE and one of the creators of SIESTA in 1996, together with Pablo Ordejón, José M. Soler and Daniel Sánchez-Portal.

However, there are systems that these theories have not managed to describe accurately: those displaying strong electronic correlations in complex molecules, such as hemoglobin, or in materials with structural defects. Quantum computers offer a promising means for tackling these problems.

But integrating the two worlds is no mean task. The architectures and physical principles underpinning HPC and quantum computers are radically different, which means that the same code cannot be reused. Even so, both systems will have to collaborate: supercomputers will remain irreplaceable for certain calculations, while quantum computers will be able to solve specific parts that are currently inaccessible. This requires the development of tools capable of translating and transferring information between both environments by integrating quantum results into classical simulations.

In this vein, nanoGUNE’s researcher Yann Pouillon is working in collaboration with IBM to enable SIESTA to access quantum computers. “Right now, we are developing software geared towards better understanding complex molecules and materials, with the aim of improving the quality of life. For example, in energy, it will enable more efficient photovoltaic cells to be designed; and in the biomedical field, it will deepen our knowledge of complex molecules such as hemoglobin, which could result in new and better therapies in the future,” explained Pouillon. “The field of quantum computing is advancing so fast that it will be crucial to develop a versatile system that allows the various advances to be rapidly incorporated. In this respect, our collaborations are expanding both locally, with DIPC for example, and internationally,” said the researcher. Pouillon aims to create a hybrid, classical-quantum platform that will provide the international scientific community using SIESTA with a pioneering tool to explore new phenomena in materials, thus connecting the classical and quantum worlds effectively. This hybridizing of SIESTA with the quantum computer will enable the scientific community and businesses to use the IBM-Euskadi Quantum Computational Center in a more accessible and broader way. “In the long term, the ideal scenario would be for the quantum computer to be like when we use graphics cards in conventional computers: a highly efficient add-on for specific tasks that an HPC cannot perform,” explained Pouillon.

This move, which also involves scientists from the nanoGUNE spin-off Simune, which offers advanced software and simulation services to technology and industrial companies, represents, according to its scientific director Mónica García-Mota, “a new impetus that positions Simune as a technological channel between state-of-the-art research and industry”. “Incorporating quantum capabilities into the SIESTA code, the engine of our ASAP (Atomistic Simulation Advanced Platform), means that we will be able to offer our industrial customers an accessible interface for solving problems involving strong electronic correlations that previously could not be tackled. This turns the ASAP into the direct route enabling companies to access the power of quantum computing, and to achieve a real, effective impact on their R&D processes,” explained García-Mota.

Video of the research: https://youtu.be/21pOgTpbYl0