The vacuum in Quantum Physics is a concept as fascinating as it is disconcerting because far from being a space devoid from all content, it represents a dynamic scene where particles and antiparticles constantly emerge and annihilate one another, guided by Heisenberg's uncertainty principle. These fluctuations in quantum vacuum, though brief, leave an indelible impression that allows for significantly improving theoretical predictions about the behaviour of subatomic particles, something that is fundamental for interpreting data in experiments such as the LHC.

Traditionally, theoretical models that predict this behaviour have been based on diagrams by Nobel Prize winner Richard Feynman, which rapidly give place to hard-to-solve complicated theoretical calculations.

The paper that has just been presented by an international scientific team, led by the Instituto de Física Corpuscular (IFIC, UV-CSIC), suggests an innovative approach that provides more precise mathematical representations in real physical processes.. The absence of infinities, along with the intrinsic quantum nature of particle physics, has allowed the scientific team to successfully implement their new algorithm in a quantum computer.

“When a mathematical formality leads to unnecessary complications, it’s usually a sign that there’s a more elegant and direct way of getting to a result,” Germán Rodrigo explains, principal investigator of the LHCPHENO group at the IFIC and leader of the study. “The method that we’ve developed clearly incorporates the fundamental physical principle of causality, or cause-and-effect. In addition to making possible more advanced theoretical predictions, it offers a new perspective to understand the enigmatic quantum properties of the vacuum state,” claims the CSIC theoretical physicist at the IFIC.

This method, published in Physical Review Letters scientific magazine, has been implemented in a quantum computer for the first time, a progress featured in another article published in Quantum Science and Technology magazine.

Applications in quantum computing

This milestone has facilitated the prediction, for the first time this types of platforms, of the Higgs boson decay rate, the elemental particle responsible for mass in the universe. Achieving this outcome in a quantum computer, in addition to validating its capacity for tackling advanced problems in theoretical physical, opens up new possibilities for the use of quantum computing in elemental particle simulations and other applications in high-energy physics.

Jorge Martínez de Lejarza, doctoral student at the IFIC and one of the authors of the last project, points out: “Quantum computers promise to revolutionise 21st century computing, surpassing classical computers in the resolution of certain specific problems. In particle physics we face some of the biggest challenges in science and, in this sense, our missions is to reformulate them to allow for their execution in quantum computers, thus, contributing to progressing toward a better understanding of the universe.”

This progress opens up new opportunities for the development of applications in quantum computing and represents a significant step in the exploration of frontiers in particle physics. Both papers have been done in collaboration with research staff from the University of Salamanca, the Autonomous University of Sinaloa (Mexico) and the CERN Quantum Technology Initiative.

References:

S. Ramírez-Uribe, P.K. Dhani, G.F.R. Sborlini and G. Rodrigo, Rewording Theoretical Predictions at Colliders with Vacuum Amplitudes, Phys. Rev. Lett. 133 (2024) 211901. DOI: https://doi.org/10.1103/PhysRevLett.133.211901

J.J.Martínez de Lejarza, D.F. Rentería-Estrada, M. Grossi and G. Rodrigo, Quantum integration of decay rates at second order in perturbation theory, Quantum Sci.Technol. 10 (2025) 2, 025026. DOI: https://doi.org/10.1088/2058-9565/ada9c5