From: John Devers ® 28/07/2001 22:41:11 Subject: Anti zeno effect? post id: 363843 Hi, the last time I posted on this subject was a thread on watched pots do not boil, this was the result of the zeno effect. Now scientists have discovered that if you watch the pot too much it can boil faster this is called the anti zeno effect. My question is what could you apply the zeno effect to and then the anti zeno effect to to make an interesting thought experiment? Is there any thing important about the zeno effect that applies to our everyday life? Would it matter to the laws of physics if the effect did not exist? http://www.nature.com/nsu/010719/010719-16.html Watching boils pot Watching boils pot Frequent check-ups could stop quantum data decaying. 18 July 2001 ERICA KLARREICH Checks can push pot over the top. PhotoDisc Good and bad news for the impatient: a watched pot can actually boil faster - but look at it too often and it may never boil at all. In a finding that offers hope for the creation of quantum computers, a new experiment has vindicated two of the most counterintuitive theories of quantum physics. The Zeno effect, proposed more than 20 years ago, predicts that frequent measurements of a quantum system will slow down or even stop the natural 'decay' of particles from high-energy states to lower-energy ones. The anti-Zeno effect, proposed just last year, predicts that numerous measurements may instead speed up decay. Although radioactive decay is a common phenomenon in the physical world - it occurs, for instance, when a radioactive atom emits a beta particle - the Zeno and anti-Zeno effects had never been observed in any spontaneously decaying system. Now Mark Raizen at the University of Texas at Austin and his colleagues have recreated both effects in the laboratory. They trapped sodium atoms in a light wave, creating a system in which the atoms could escape only by tunnelling. This is a bizarre quantum effect in which particles pop across an energy barrier that they should not theoretically have enough energy to overcome. Left to its own devices, the system would decay slowly, with sodium atoms tunnelling across the barrier every now and then. When Raizen's team observed the system every millionth of a second, the tunnelling rate slowed significantly. When they took measurements every five millionths of a second, tunnelling speeded up. "The Zeno effect has until now only been seen in very simple systems, and the anti-Zeno effect has never been seen," says Abraham Kofman at the Weizmann Institute in Israel, who first predicted the anti-Zeno effect with colleague Gershon Kurizki. "It's an outstanding experiment, in the spirit of the original proposal of the Zeno effect." It may seem paradoxical that mere observation should alter the course of events. But on the quantum level, it's a fact of life. According to quantum theory, before a particle is measured, it exists in an indecisive blur of states, hovering on both sides of a barrier at the same time. Measuring a particle entails bouncing at least one photon off it. This creates enough of a disturbance to push a particle into a definite state, either outside or inside the barrier. Where the particle lands depends on the timing of the measurement. "Once we measured it, we prevented a particle from hopping back to the undecided state," says Martin Fischer, a member of the research team who is now with the New Jersey-based microelectronics company Agere Systems. The Zeno effect offers the tantalizing possibility of eventually helping to solve one of quantum computing's biggest problems: errors arising from the decay of data. "This paper gives some encouragement, since it shows that it is possible to achieve the Zeno effect in some cases," Kofman says - in other words, to halt decay. Zeno was a philosopher of fourth century BC Greece who argued that motion is impossible. References Fischer , M. C.et al. Observation of the Quantum Zeno and Anti-Zeno effects in an unstable system. Physical Review Letters This forum is un-moderated. The views and opinions expressed are those of the individual poster and not the ABC. The ABC reserves the right to remove offensive or inappropriate messages.