Coherence was a really fun movie shot an absolute shoestring budget but it's about like a magic comet that unlocks parallel universes at a dinner party. It's high-concept sci-fi and not realistic at all.
But it isn't about physics. It's overall theme is somewhat cryptic but it is making statements. It is less cryptic than Coen's other films like Barton Fink.
If you haven't seen the Coen Brother's filmography, start with A Serious Man. It's the kind of movie that gives you nostalgia for loneliness. It probably could have helped me in my teenage years. It's undoubtedly a cathartic movie for those who have had unfortunate luck or feel misunderstood.
In that case, it is about physics. More specifically, my experience as a graduate student sitting in QCD lectures.
There's a phrase that's repeated again and again (in one way or another), which is "but I didn't _do_ anything".
This is a pretty good video: https://www.youtube.com/watch?v=3vDmWFTvzto
Although, I think a lot of the analysis of Coen brothers can sometimes fall flat. Coen brothers films are hilarious, often in extremely dark and non-obvious ways, so oftentimes their films are overanalyzed. I often think answers to "why did the Coen brothers put this in the film?" are simply "because they thought it was funny".