Elfner develops dynamical computation simulations to better understand high energy conditions and the
quark–gluon plasma. She became interested in the influence of the initial and final states on the trajectory of
heavy ion collisions. To quantitatively evaluate the impact of these boundary conditions, she adopted an event-by-event strategy that makes use of transport theory. She developed a hadronic transport approach known as SMASH (Simulating Many Accelerated Strongly-interacting Hadrons). SMASH is part of the
National Science Foundation JETSCAPE framework. Her model predicted that the dynamics and viscosity of the plasma depends on the initial state and any quantum fluctuations. In 2011, Elfner was appointed a visiting professor at
Duke University where she was based in the
quantum chromodynamics group. She decided to return to Germany because of the creation of the accelerator FAIR (
Facility for Antiproton and Ion Research). She was one of the youngest researchers to ever be appointed professor in Germany. Elfner was made Head of Simulations at the Helmholtz Centre for Heavy Ion Research in 2018. == Awards and honors ==