Experimental realization of quantum zeno dynamics

TLDR

Quantum systems cannot be probed without disturbance, yet measurement back‑action and strong couplings can be harnessed to tailor and protect coherent evolution—a counterintuitive phenomenon known as quantum Zeno dynamics. The study demonstrates quantum Zeno dynamics in a rubidium Bose‑Einstein condensate spanning a five‑level Hilbert space. Measurements and strong couplings are used to dynamically disconnect state groups, confining the atoms to coherent evolution within a two‑level subregion. The experiment realizes a dynamical superselection rule, advancing protection and control of quantum dynamics and quantum information processing.

Abstract

It is generally impossible to probe a quantum system without disturbing it. However, it is possible to exploit the back action of quantum measurements and strong couplings to tailor and protect the coherent evolution of a quantum system. This is a profound and counterintuitive phenomenon known as quantum Zeno dynamics. Here we demonstrate quantum Zeno dynamics with a rubidium Bose-Einstein condensate in a five-level Hilbert space. We harness measurements and strong couplings to dynamically disconnect different groups of quantum states and constrain the atoms to coherently evolve inside a two-level subregion. In parallel to the foundational importance due to the realization of a dynamical superselection rule and the theory of quantum measurements, this is an important step forward in protecting and controlling quantum dynamics and, broadly speaking, quantum information processing.