Wednesday, July 28, 2010

"Switching Off" the Heisenberg Uncertainty Principle

A new scheme in quantum information measurement has been proposed that might, under certain situation, defeat the limit imposed by the Heisenberg Uncertainty principle (HUP). Instead of gathering information about the state from a "classical memory", the "... particle is prepared entangled with a quantum memory.. ", which is still a device that we do not have yet.

Heisenberg’s uncertainty principle applies wherever predictions about measured quantum mechanical variables are made on the basis of classical data. It arises due to the fact that, in quantum mechanics, there are no clearly defined 0 and 1 states like those of a bit in a classical computer, and instead several alternative possibilities can exist simultaneously. “If we collect the available information about a particle in a quantum memory, this makes this information more valuable than information gathered in a classical way,” says Renato Renner, Assistant Professor at the Institute for Theoretical Physics of ETH Zurich and co-author of the paper. These quantum data then theoretically allow measured variables to be predicted with any desired precision, and the Heisenberg uncertainty becomes arbitrarily small.
We will just have to see if such a quantum memory can be produced.



Julie said...

Question here: I thought the measurement of a particular (if possible without interference) caused the superposition of state to collapse into one of two possible states. Isn't this the Shrodinger's cat analogy? There are two possibilities: 50% dead/50% alive and the mere observation dictates which one it is. You seem to be saying here that more than two possibilities exist in a quantum mechanical context. Do I understand you correctly?

Jarod said...

It only collapses into two states because the cat can either be dead or alive. Its the example used that provides us with only two possible states.