Les calclateurs quantiques nous aideront à mieuxc comprendre ce qui se passe au cœur du LHC du CERN (Grand Accélérateur-Collisionneur de particules). Ils devraient faire bien mieux, en nous introduisant progressivement au coeur de la physique fondamentale, physique nucléaire et physique des particules.
Deux groupes de chercheurs, dans deux expériences différentes, dont on trouvera ci-dessous les références et les résumés, en ont apporté la preuve. Il s’agissait de montrer comment des particules chargées donc très énergétiques, se comportaient dans des champs quantiques analogues à ceux que l’on rencontre dans la théorie quantique des champs
https://fr.wikipedia.org/wiki/Th%C3%A9orie_quantique_des_champs
Ceux-ci s’étendent à travers l’espace et exercent des forces sur les particules comme sur les astres. L’on commence seulement à découvrir leurs analogues, à une toute autre échelle, dans les accélérateurs.
Les chercheurs utilisèrent des calculateurs quantiques extrêmement refroidis et commandés par des lasers. Nous n’insisterons pas ici sur ces expériences qui sortent du cadre de cet article. Leurs auteurs estiment que des calculateurs quantiques de plus grande taille pourraient aborder des questions aujourd’hui sans réponses, tant en physique des particules qu’en cosmologie.
Sources
Published: 04 June 2025
Observation of string breaking on a (2 + 1)D Rydberg quantum simulator
Nature volume 642, pages 321–326 (2025
Abstract
Lattice gauge theories (LGTs) describe a broad range of phenomena in condensed matter and particle physics. A prominent example is confinement, responsible for bounding quarks inside hadrons such as protons or neutrons1. When quark–antiquark pairs are separated, the energy stored in the string of gluon fields connecting them grows linearly with their distance, until there is enough energy to create new pairs from the vacuum and break the string. Although these phenomena are ubiquitous in LGTs, simulating the resulting dynamics is a challenging task2. Here we report the observation of string breaking in synthetic quantum matter using a programmable quantum simulator based on neutral atom arrays3,4,5. We show that a (2 + 1)-dimensional LGT with dynamical matter can be efficiently implemented when the atoms are placed on a Kagome geometry6, with a local U(1) symmetry emerging from the Rydberg blockade7. Long-range Rydberg interactions naturally give rise to a linear confining potential for a pair of charges, allowing us to tune both their masses and the string tension. We experimentally probe string breaking in equilibrium by adiabatically preparing the ground state of the atom array in the presence of defects, distinguishing regions within the confined phase dominated by fluctuating strings or by broken string configurations. Finally, by harnessing local control over the atomic detuning, we quench string states and observe string-breaking dynamics exhibiting a many-body resonance phenomenon. Our work provides opportunities for exploring phenomena in high-energy physics using programmable quantum simulators
Visualizing dynamics of charges and strings in (2 + 1)D lattice gauge theories
Nature volume 642, pages 315–320 (2025)
Abstract
Lattice gauge theories (LGTs)1,2,3,4 can be used to understand a wide range of phenomena, from elementary particle scattering in high-energy physics to effective descriptions of many-body interactions in materials5,6,7. Studying dynamical properties of emergent phases can be challenging, as it requires solving many-body problems that are generally beyond perturbative limits8,9,10. Here we investigate the dynamics of local excitations in a Lattice gauge theories (LGTs)1,2,3,4 can be used to understand a wide range of phenomena, from elementary particle scattering in high-energy physics to effective descriptions of many-body interactions in materials5,6,7. Studying dynamical properties of emergent phases can be challenging, as it requires solving many-body problems that are generally beyond perturbative limits8,9,10. Here we investigate the dynamics of local excitations in a GT using a two-dimensional lattice of superconducting qubits. We first construct a simple variational circuit that prepares low-energy states that have a large overlap with the ground state; then we create charge excitations with local gates and simulate their quantum dynamics by means of a discretized time evolution. As the electric field coupling constant is increased, our measurements show signatures of transitioning from deconfined to confined dynamics. For confined excitations, the electric field induces a tension in the string connecting them. Our method allows us to experimentally image string dynamics in a (2+1)D LGT, from which we uncover two distinct regimes inside the confining phase: for weak confinement, the string fluctuates strongly in the transverse direction, whereas for strong confinement, transverse fluctuations are effectively frozen11,12. We also demonstrate a resonance condition at which dynamical string breaking is facilitated. Our LGT implementation on a quantum processor presents a new set of techniques for investigating emergent excitations and string dynamics.
Europe Solidaire 