The article by the researchers of Sharif University of Technology was included in the list of worthy researches of the International Gravity Research Foundation in 2023.
An article entitled "Dynamic dark energy derived from the local limit of the non-local theory of gravity" by Javad Tabatabaei, a PhD student, Dr. Abdul Ali Bani Hashemi, a postdoctoral researcher, and Dr. Shant Bagram, an associate professor at the Faculty of Physics of Sharif University of Technology, along with Dr. Bahram Mashhoun, a retired professor at the University of Missouri and an associate professor at the research school. Astronomy of the Research Institute of Fundamental Sciences and Faculty of Physics of Sharif University of Technology was included in the list of honorees of the International Gravity Research Foundation this year.
It is stated in this article; 95% of the universe consists of matter and dark energy, the physics of both of these components is unknown, and our observation and perception of the two dark components of the universe is only through gravity. Therefore, there is always the idea that maybe there is a more fundamental model for classical gravity. A more fundamental theory with which these two components are somehow related.
Einstein's general relativity is based on two important principles. The principle of equivalence (equivalence of gravitational mass and dead mass) and the principle of position! The principle of locality means that physics measurements are done locally and only at one point in space and time. Interestingly, there are physical phenomena such as "waves" that indicate the non-local nature of measurement. Therefore, we can seek to build a non-local theory of relativity and gravity.
This idea has been extensively analyzed in the book Nonlocal Gravity by Professor Mashhoon, which was published in 2017 by Oxford Publishing.
In the new research; Tabatabai et al have obtained the local limit of non-local gravity for the homogeneous and isotropic universe. In this article and another supplementary article, they have shown that the evolution of the constituents of the universe will be different from the standard model! Specifically, in this model, the space geometry of the universe is flat, and the cosmological constant, as a component that has a constant density, cannot be the cause of the accelerated expansion of the universe. In other words, it is the accelerating expansion of dynamical dark energy. This research group is investigating different aspects of this non-local theory of gravity and its effects on cosmology.