Quantum Zeno Effect Induced by Collisions

Abstract

It is proven experimentally that the ortho-para conversion of the nuclear spin isomers of ${}^{13}{\mathrm{CH}}_{3}\mathrm{F}$ molecules can be slowed down by increasing the gas pressure. The observed ``freezing'' of the molecular quantum states can be considered as an example of the quantum Zeno effect induced by collisions.