Terahertz collisions

摘要

It comes so naturally to us. To get a handle on new objects, say two marbles, children bounce them off each other to see whether they scatter or break. Scientists hunting for new phenomena in quantum physics are no less captivated by the idea of colliding atoms or elementary particles. Intense lasers have become a strong ally in that pursuit, ever since it was discovered that their oscillating electric field can rip an electron from an atom through quantum-mechanical tunnelling.