Dark Matter - Juli Zeh

Sebastian and Oskar have been friends since their days studying physics at university, when both were considered future Nobel Prize candidates. But their lives took divergent paths, as did their scientific views. Whenever Oskar comes to visit from his prestigious research post in Geneva, there is tension in the air, and it doesn't help their friendship that he feels Sebastian has not lived up to his intellectual capacities, having chosen marriage and fatherhood as an exit strategy.