Graviton-like modes – link and some questions

Recently, I wrote a blog on Graviton-like modes in solids.

There is a nice report from the Columbia Quantum Initiative on the Nature paper.

It highlights the role of Aron (a key author in the paper, who passed away in 2022) and his legacy.

Undoubtedly, the graviton-like connection has created a buzz. As the above report mentions, it has also taken a lot of time and effort on the part of the authors to measure it.

Thanks to my colleague Surjeet Singh, I also learnt about the importance of heterostructures in this work and that authors do not oversell the connection to gravitons in the paper.

For me, as an outsider to the field(s), a few questions remain:

• What lessons can we learn from graviton-like modes in solids that will help us understand the actual undetected graviton?
• How is it different from the collective excitation of quasiparticles, such as exciton-polaritons in semiconductor heterostructures? Similar experimental methods are used to study them. 
• Is the prominence only due to spin-2 collective excitation? 
• Finally – applying Occam’s razor – can there be a simple explanation without evoking graviton-like modes?

It would be great to know the answers, hopefully, in the coming days.