The cavalier start of electrons in a crystal does not remain without consequences for their further destiny. This is reported by the Berlin researchers Peter Gaal, Wilhelm Kühn, Klaus Reimann, Michael Woerner and Thomas Elsässer of the Max Born Institute, and Rudolf Hey of the Paul Drude Institute in the latest issue of the journal Nature (Vol 450, page 1210). They studied the ultrafast motion of electrons in a gallium arsenide crystal exposed to a very high electric field for a short time. This conceptually new experiment shows for the first time a collective, ultra-high-frequency tremor movement of the electrons, which occurs in addition to the known spatial drift of these particles. The newly discovered effect could play an important role in the miniaturization of electronic components.