发布日期：2026-08-07
点击次数：
标题：The Hubble tension and other astrophysical issues in the context of scale invariance
时间：2026-8-25,10:30
主讲人：Fred Courbin (U of Barcelona, Spain)
地点：Physics Building E101
报告语言：English
Cosmological models require a gage. One of them, considered already by Dirac is to consider that gravity is scale invariant in the vacuum (SIV). This was abandoned as the Universe is not completely empty, but as always in science everything is a matter of approximation. Assuming the universe is sufficiently empty, Maeder re-considered SIV and showed that it can easily explain phenomenon over a broad range (and scales!), such as the recession of the Moon, galaxy rotation curves, wide binary stars, gravitational lensing, and more recently the Hubble tension, without invoking any dark energy. I will briefly describe the theory which hold on a first-principle assumption rather than endless epicycles and focus on how it may solve the Hubble tension exactly.
BIO:
I work mostly in observational cosmology with gravitational lensing in all regimes: strong, weak and micro, addressing the problems of Dark Matter, Dark Energy and primordial black holes as well as the study galaxy formation and evolution, quasar inner structure, quasar/galaxy co-evolution. A strong component of my research also resides in pure signal/image processing, with expertise in ill-posed inverse problems, often central to interpret astrophysical observations. I am a regular user of HST, JWST, and most world-class telescopes. In 2022, I was nominated Swiss representative on the ESO Scientific and Technical Committee. My main achievement has been to transform the field of time delay cosmography from a niche topic to a competitive cosmological probe to address the Hubble tension, one of the most important challenges in modern cosmology. This was acknowledged by my COSMICLENS ERC AdG in 2018. This work also led to the RedH0T ERC Synergy project in 2025, of which I am one of the 4 PIs with Licia Verde, Julien Lesgourgues and Adam Riess.
Host: Dandan Xu
