After obtaining his doctorate he joined Carl Wieman at the University of Colorado Boulder as a postdoctoral researcher on a small laser cooling experiment. During his two years as a postdoc he came up with a plan to combine laser cooling and evaporative cooling in a magnetic trap to create a Bose–Einstein condensate (BEC). Based on his proposal he was offered a permanent position at JILA/NIST in Boulder. For synthesizing the first Bose–Einstein condensate in 1995, Cornell, Wieman, and Wolfgang Ketterle shared the Nobel Prize in Physics in 2001.