QUANTUM BREAKING OF ELASTIC STRING

Breaking of an atomic chain under stress is a collective many-particle tunneling phenomenon. We study classical dynamics in imaginary time b y using a conformal mapping technique, and derive an analytic formula for the probability of breaking. The result covers a broad temperature interval and interpolates between two regimes: tunneling and thermal activation. Also, we consider the breaking induced by an ultrasonic wa ve propagating in the chain, and propose to observe it in a scanning t unneling microscopy experiment.