The motion of electrons in atoms, molecules, or crystals is of fundamental importance for a vast range of fields in science and technology. Our work opens the way to controlling and exploring this motion on atomic and molecular-length scales.

Yes, it describes a technique that allows steering electrons on atomic length and time scales for the first time.

The most direct control of processes as fundamental as chemical reactions or light emissions can be accomplished by precisely controlling the motion of the electrons that participate in chemical bonds or create an atomic dipole moment, respectively. To this end, a force variable on atomic and molecular time scales—within a millionth of a billionth of a second—and comparable in strength to the atomic Coulomb force binding the electrons to the nuclei, is required. By precisely controlling the electric field oscillations which occur in ultraintense pulses of few-cycle laser light, we have provided such a force. With this new tool we believe researchers will be able to find out about how electrons team up to form chemical bonds between neighboring atoms and how the creation or breakage of these bonds can be precisely controlled by light forces to form new molecules. Of equal importance, we may also be able to find out more about how electrons, upon their motion deep inside the interior of atoms, emit X-rays and how we can make them do so in a concerted action in order to achieve X-ray laser emission.