Imaging Ultrafast Quantum Dynamics on the Nanoscale

Coherence is at the heart of ultrafast electronic processes in atomic, molecular and solid systems. A brief perturbation by a light field causes a coherent response, transferring the coherence of the field to the dynamics of the electrons. The time scale associated with coherent quantum dynamics in those systems is in the attosecond domain (1 as = 10-18 s). However, decoherence destroys the coherent evolution on time scales ranging from femtoseconds to nanoseconds. Fast decoherence, the intrinsic time scales and picometer to nanometer length scales make the direct observation of coherent dynamics challenging. In my talk I will present two new approaches to provide simultaneous spatial and temporal imaging of coherent quantum dynamics, ultrafast scanning tunneling microscopy (STM) and electron holography. Here we will utilize electron wavepackets with attosecond to femtosecond temporal duration and Ångström to nanometer spatial confinement. I will present the current progress in our research and the physics questions that we will be able to address.