Monitoring could slow quantum data decay
July 20, 2001 | Source: Nature Science Update
In a finding that offers hope for the creation of quantum computers, frequent measurements have been found to slow down the “decay” of particles from high-energy states to lower-energy ones.This support for the “Zeno effect” offers the possibility of eventually helping to solve one of quantum computing’s biggest problems: errors arising from the decay of data.
Mark Raizen at the University of Texas at Austin and his colleagues 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.
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.