Mimetic gravity

Advanced Science news coverage for EHT and mimetic gravity paper

EHT and mimetic gravity paper published in Scientific Reports!

My paper with Mohsen Khodadi and Javad Firouzjaee, where we show that the EHT observations of M87* and Sgr A* rule out the baseline version of mimetic gravity (see this earlier news item), has now officially been published in Scientific Reports (making this my second proper Nature publication)! The full bibliographic coordinates for the paper are Sci. Rep. 14 (2024) 26932. Here is the link to the paper (which is published Open Access).

EHT and mimetic gravity paper accepted in Scientific Reports!

My paper with Mohsen Khodadi and Javad Firouzjaee, where we show that the EHT observations of M87* and Sgr A* rule out the baseline version of mimetic gravity (see this earlier news item), has been accepted for publication in Scientific Reports, part of the Nature Portfolio collection of journals (therefore making this my second proper Nature publication)! The most significant addition compared to the earlier version is a new figure with examples of null geodesics in the space-times we studied, which shows in a very clear way why their shadow properties are pathological. You can read the preprint version of the paper on arXiv: 2408.03241.

EHT and mimetic gravity

Another exciting paper out today! With Mohsen Khodadi and Javad Firouzjaee, we show that the Event Horizon Telescope (EHT) observations basically rule out compact objects in mimetic gravity, a framework of modified gravity which has received a lot of interest as a candidate for explaining both dark matter and dark energy, and first proposed (explicitly) by Mukhanov and Chamseddine in 2013. Mohsen and collaborators studied compact objects in mimetic gravity in 2020, finding them to be highly non-trivial: in practice, the theory supports only a naked singularity, and a black hole obtained through a particular gluing procedure. What we showed in today’s paper is that the shadow properties of both these space-times are pathological, since the naked singularity does not cast a shadow, whereas the black hole casts a shadow which is way too small: for these reasons, both compact objects (and by extension mimetic gravity or, more precisely, the baseline version proposed in 2013) appear to be excluded by the EHT images of M87* and Sgr A*. You can read our results in the preprint we just posted on arXiv: 2408.03241.