Perspectives on the quantum Zeno paradox

As of October 2006, there were approximately 535 citations to the seminal 1977 paper of Misra and Sudarshan that pointed out the quantum Zeno paradox (more often called the quantum Zeno efiect). In simple terms, the quantum Zeno efiect refers to a slowing down of the evolution of a quantum state in the limit that the state is observed continuously. There has been much disagreement as to how the quantum Zeno efiect should be deflned and as to whether it is really a paradox, requiring new physics, or merely a consequence of " quantum mechanics. The experiment of Itano, Heinzen, Bollinger, and Wineland, published in 1990, has been cited around 347 times and seems to be the one most often called a demonstration of the quantum Zeno efiect. Given that there is disagreement as to what the quantum Zeno efiect is, there naturally is disagreement as to whether that experiment demonstrated the quantum Zeno efiect. Some difiering perspectives regarding the quantum Zeno efiect and what would constitute an experimental demonstration are discussed.