Zitterbewegung, which means “trembling motion” in German, is a predicted rapid oscillatory motion of relativistic particles such as electrons when described by the Dirac equation—the fundamental equation combining quantum mechanics and special relativity.
According to theory, this trembling arises from the interference between positive and negative energy states of the electron, causing it to exhibit extremely fast, tiny oscillations around its average position. The frequency of this motion is extraordinarily high, and the amplitude is incredibly small, making direct experimental observation extremely challenging.
Although initially a theoretical curiosity, Zitterbewegung has analogues in various modern quantum systems, such as trapped ions and graphene, where similar trembling-like effects can be studied. Understanding this phenomenon helps deepen insights into relativistic quantum mechanics and the behavior of fundamental particles.