Just based off this google search: http://scholar.google.com/scholar?hl=en&q=rigetti&btnG=&as_sdt=1%2C5&as_sdtp= http://scholar.google.com/scholar?hl=en&q=riget

Just based off this google search: http://scholar.google.com/scholar?hl=en&q=rigetti&btnG=&as_sdt=1%2C5&as_sdtp= http://scholar.google.com/scholar?hl=en&q=rigetti&btnG=&as_s... I'm going to guess it's Josephson Junction based. Possibly similar to D-Wave in that it's based on adiabatic computing and focused on specific optimization problems. Details from the horse's mouth have been super sparse though.