Resumen: We unveil the multifractal behavior of Ising spin glasses in their low-temperature phase. Using the Janus II custom-built supercomputer, the spin-glass correlation function is studied locally. Dramatic fluctuations are found when pairs of sites at the same distance are compared. The scaling of these fluctuations, as the spin-glass coherence length grows with time, is characterized through the computation of the singularity spectrum and its corresponding Legendre transform. A comparatively small number of site pairs controls the average correlation that governs the response to a magnetic field. We explain how this scenario of dramatic fluctuations (at length scales smaller than the coherence length) can be reconciled with the smooth, self-averaging behavior that has long been considered to describe spin-glass dynamics. Idioma: Inglés DOI: 10.1073/pnas.2312880120 Año: 2024 Publicado en: Proceedings of the National Academy of Sciences of the United States of America 121, 2 (2024), e312880120 [7 pp.] ISSN: 0027-8424 Factor impacto JCR: 9.1 (2024) Categ. JCR: MULTIDISCIPLINARY SCIENCES rank: 14 / 135 = 0.104 (2024) - Q1 - T1 Factor impacto SCIMAGO: 3.414 - Multidisciplinary (Q1)