First round is a phone interview that lasts 30 minutes or so. After the 1st round, they invited me for an on-site interview. Mostly the usual stuff, asked about my background and experience. Then the rest is technical questions.

Interviewed out of phd program. They try to pair you up with researchers who have similar academic backgrounds, at least in the first few rounds. They seem interested in hearing about your research, but probably wise to stress those aspects that are relevant to quant finance if possible (coding, stats, automation).