Ultrafast single-molecule videography and choreography

To understand the function of condensed matter, it would be desirable to directly watch its atomistic building blocks dynamically interact on their intrinsic length and time scales. Recently, lightwave electronics has made this long-standing dream come true. The idea is to exploit the carrier wave of light as an ultrafast, contact-free bias to interrogate and control the nanocosm. I will first review how lightwaves can drive electrons in solids into surprising sub-cycle quantum motion. By combining this idea with the sub-angstrom spatial resolution of scanning tunnelling microscopy we can set an ultrashort time window for single-electron tunnelling into a single orbital and record first atom-scale slow-motion movies of individual vibrating molecules. Finally, I will show how to directly exert femtosecond atomic forces, which can selectively choreograph a coherent structural motion of a single-molecule switch in its electronic ground state. This stunningly direct access to the atomistic world may tailor key elementary dynamics in nature and steer (bio)chemical reactions or ultrafast phase transitions, on their intrinsic spatio-temporal scales.