No, it is not recording and retransmitting
on
Stopping Light
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· Score: 1
Many of you said that this result is not revolutionary because it is just recording and retransmitting information which has been around for a long time. I am a quantum physicist and would like to offer some clarification in order to better see the difference.
The keyword here is "quantum" information. Light (or any other particle or anything for that matter) carries a set of physical information (speed, position, energy, angular momentum, etc.). Heisengberg's rule however tells us that there is no way to measure all this information at the same time with arbitrary precision. Measuring one characteristics basically destroys the information about something else, therefore recording and retransmitting is always confined to a subset of the physical quantities.
For those who know some physics: for example you can measure the x-component of the angular momentum but the very measurement loses _all_ information about the y-component of the angular momentum. The x-component of the retransmitted light's angular momentum might be identical to the original one's but the y-component necessarily differs.
Therefore the challenge in stopping light is the following: you want to confine the information carried by light to a small region of space _without_ actually detecting that information. This is what has been achieved in these experiments: when one retransmits the light previously captured, it will carry the same quantum properties as the original incoming light. And this is definitely something very new.
Slashdot Mirror
Many of you said that this result is not revolutionary because it is just recording and retransmitting information which has been around for a long time. I am a quantum physicist and would like to offer some clarification in order to better see the difference.
The keyword here is "quantum" information. Light (or any other particle or anything for that matter) carries a set of physical information (speed, position, energy, angular momentum, etc.). Heisengberg's rule however tells us that there is no way to measure all this information at the same time with arbitrary precision. Measuring one characteristics basically destroys the information about something else, therefore recording and retransmitting is always confined to a subset of the physical quantities.
For those who know some physics: for example you can measure the x-component of the angular momentum but the very measurement loses _all_ information about the y-component of the angular momentum. The x-component of the retransmitted light's angular momentum might be identical to the original one's but the y-component necessarily differs.
Therefore the challenge in stopping light is the following: you want to confine the information carried by light to a small region of space _without_ actually detecting that information. This is what has been achieved in these experiments: when one retransmits the light previously captured, it will carry the same quantum properties as the original incoming light.
And this is definitely something very new.
Tamas