pendell
2011-06-07, 09:13 AM
link (http://physicsworld.com/cws/article/news/46193).
This appears to be another attempt to fathom the mysteries of wave-particle duality. The technique is called "weak measurement".
The theory of “weak measurement” first proposed in 1988 and developed by physicist Yakir Aharonov and his group at Tel Aviv University, Israel, has seen a fair amount of interest in recent years. The theory states that it is possible to “weakly” measure a system and so gain some information about one property without appreciably disturbing the complimentary property and so the future evolution of the entire system. Though the information obtained for each measurement is minimal, an average of multiple measurements gives an accurate estimation of the measurement of the property without distorting its final outcome.
In their experiment, the researchers sent an ensemble of single photons through a two-slit interferometer and performed a weak measurement so as to imprecisely measure the momentum of each photon. This was done using a piece of calcite, which serves as a polarizer. Depending on the direction of propagation each photon is differently polarized and the direction is measured as a function of position. This was then followed by an extremely accurate measurement of the final position of where each photon hits the “screen”, which in their case, was a camera. By combining the positions measured imprecisely at multiple points and the momentum precisely measured at the end for each photon, they were able to accurately construct an entire flow pattern for the photons.
“This weak momentum measurement does not appreciably disturb the system, and interference is still observed. Both measurements had to be repeated on a large ensemble of particles in order to gain enough information for the whole system, but we did not disturb the outcome at all.” explains Steinberg. "Our measured trajectories are consistent, as Wiseman had predicted, with the realistic but unconventional interpretation of quantum mechanics of such influential thinkers as David Bohm and Louis de Broglie,"
So, my question for the physicists in the playground.
1) If true, what impact does it have on our understanding of quantum mechanics?
2) The engineer in me wants to know what practical applications could be made of this discovery? Even if there is no direct application, might it down the road lead to something useful? And of course better understanding the cosmos we live in is always worthwhile.
Respectfully,
Brian P.
This appears to be another attempt to fathom the mysteries of wave-particle duality. The technique is called "weak measurement".
The theory of “weak measurement” first proposed in 1988 and developed by physicist Yakir Aharonov and his group at Tel Aviv University, Israel, has seen a fair amount of interest in recent years. The theory states that it is possible to “weakly” measure a system and so gain some information about one property without appreciably disturbing the complimentary property and so the future evolution of the entire system. Though the information obtained for each measurement is minimal, an average of multiple measurements gives an accurate estimation of the measurement of the property without distorting its final outcome.
In their experiment, the researchers sent an ensemble of single photons through a two-slit interferometer and performed a weak measurement so as to imprecisely measure the momentum of each photon. This was done using a piece of calcite, which serves as a polarizer. Depending on the direction of propagation each photon is differently polarized and the direction is measured as a function of position. This was then followed by an extremely accurate measurement of the final position of where each photon hits the “screen”, which in their case, was a camera. By combining the positions measured imprecisely at multiple points and the momentum precisely measured at the end for each photon, they were able to accurately construct an entire flow pattern for the photons.
“This weak momentum measurement does not appreciably disturb the system, and interference is still observed. Both measurements had to be repeated on a large ensemble of particles in order to gain enough information for the whole system, but we did not disturb the outcome at all.” explains Steinberg. "Our measured trajectories are consistent, as Wiseman had predicted, with the realistic but unconventional interpretation of quantum mechanics of such influential thinkers as David Bohm and Louis de Broglie,"
So, my question for the physicists in the playground.
1) If true, what impact does it have on our understanding of quantum mechanics?
2) The engineer in me wants to know what practical applications could be made of this discovery? Even if there is no direct application, might it down the road lead to something useful? And of course better understanding the cosmos we live in is always worthwhile.
Respectfully,
Brian P.