first round. in the format of phone or zoom. I was asked some math questions/basic physics questions. Some of them are like middle school math contest questions. Some of the focus on signal processing. I don't remember all of them. But if you are good in high school. you will be fine.

I was interviewed by only one person. They asked me why I wanted to work for them and my skills. They asked me about my thesis and if I was avaiable to move out of my country.

Two rounds of phone interviews. First round to describe yourself about your research and so on and asked some simple math question. Second round asked some brain teaser and more math questions