Professor Claudia Eberlein
I am Professor of Theoretical Physics, and my research area is quantum electrodynamics. I deal with quantum systems, small things, that are close to something big, for example an isolated atom that is close to a mirror.
The atom “feels” the mirror at a distance through the light reflected from it, and thus the mirror changes the atom – despite never touching it. This can be used for building tiny lasers, like the ones that are found in CD and DVD players, or in future perhaps for building new quantum computers.
The object I am holding is a Newton’s cradle. Letting the steel balls bounce off each other, one sees that momentum is conserved in collisions. For them, momentum is mass times velocity.
Surprisingly, even though light does not have any mass, it also has momentum. When light bounces off an atom or a mirror, the total momentum stays the same, just like for the steel balls.