Subsequently, he worked at the University of Texas at Austin until 1996 as postdoctoral fellow of the National Science Foundation, with Peter J. Rossky as his mentor.
In the summer of 2001, he worked as visiting faculty at the Center for Non-Linear Studies at Los Alamos National Lab and in 2023 he served as the Ulam Distinguished Scholar in the CNLS.
He has worked at the University of Cambridge, the École Normale Supérieure, Paris, and at Los Alamos National Lab[5] and has collaborated, among others, with Robert E.
They have worked on energy transfer in DNA molecules using methods of molecular dynamics, time-dependent density functional theory (TD-DFT) and analytical lattice models.
His APS Fellowship citation reads: “For developing theoretical and computational descriptions of quantum dynamics in molecular systems, especially for their use in understanding the migration of energy and charge in molecular electronic excited states.” Bittner has received several grants and awards for his work:[1][6][7] The John and Rebecca Moores professorship was awarded to him as recognition for "outstanding work in both research and teaching".