QUELLE EST L'ÉNERGIE DU VIDE ?

Conference as part of the TimeWorld World Scientific Congresses: TimeWorld presents and promotes knowledge in all its forms: theoretical, applied, and prospective. TimeWorld offers a state-of-the-art presentation on a major theme, with a multicultural and interdisciplinary approach. It provides an opportunity for researchers, industry, academics, artists, and the general public to meet to generate scientific ideas and develop new projects. https://timeworldevent.com/fr/ ------------------------------------------------------------------------ Bruno Mansoulié is a physicist at the CEA, in the particle physics department, which he directed for five years. He has contributed to several important discoveries in the field, including the W and Z particles at CERN in 1984, the top quark at Fermilab (USA) in 1995, and the famous Higgs boson at CERN in 2012. He has been a member since its inception (1992) of the international ATLAS collaboration, which built one of the two huge detectors at the LHC, CERN's large proton collider. After the start of the LHC in 2008, he was part of the data analysis team searching for the Higgs boson. After its discovery in 2012 by the ATLAS and CMS collaborations, he led the ATLAS teams that extended and crossed measurements on this new particle, thus allowing precise comparisons with theory. For this work he received the 2023 Charpak-Ritz Prize from the French Physical Society and the Swiss Physical Society. Deeply committed to the dissemination and questioning of science, Bruno Mansoulié has given numerous lectures open to the public and published two books for the general public. Lecture: What is the energy of the vacuum? November 18, 2023, at the Cnam in Paris during the TimeWorld Energy conference. Our universe is expanding, and this expansion is accelerating. For the theory of general relativity, this acceleration is due to a parameter that can be interpreted as the energy of the cosmic vacuum. Thanks to observations over the past few decades, the value of this parameter is now known with good precision. For quantum theory, which claims to understand the elementary fields and particles present in the universe, vacuum energy is an ill-defined concept but should not be included in calculations, where it plays only a background role. However, the confrontation of these two visions raises one of the most important problems in fundamental physics. In the lecture, I will try to describe in simple words the two theoretical views, where the problem lies, and why it is impossible to ignore it today.