When Electrons Go Wild!

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Eeezee

Diamond Member
Jul 23, 2005
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Originally posted by: silverpig
Originally posted by: Eeezee
Originally posted by: silverpig
Originally posted by: Fenixgoon
so if i interpreted the news article correctly.. that movie is showing the change in energy distribution of a single electron (or is it an atom?) as it is hit by light.
From what I get from the story they are showing the point at which an electron leaves an atom can be changed by changing the timing between laser pulses. What you are looking at is an image of recorded positions of electrons hitting a detector. When the images shifts, that's indicating the point at which the electron leaves the atom is shifting.
But then that's not really a movie of an electron at all, but rather a video of a change in detection position. This is a fine experimental method, but I think the title of the video is a bit misleading.

This would be like claiming that a video of a person's footprint in the sand is a video of the person (obviously a person was there, but you've just taped the consequence, not the actual person)
They're taking a video of the quantum state of an electron in a helium atom. Sure different electrons are invovled, but because they're identical, and come from the same state, it's fine to say this.

A better analogy would be to say I made a movie of you walking to work by taking one picture of you a day. The first one is of you leaving your front door, then the next day I take a picture a second after you leave your front door. The next day I take a picture of you 2 seconds after leaving your door etc, then build them up into a movie. You're the same person every day, and electrons don't wear clothes, so by doing this I could make a movie of you walking to work.
I already knew that aspect, I just misread the article - it was a PHOTON scattering off of the atom (not an electron, which is what I thought they originally meant - that they were taking a picture of the scattered electron by watching the oscillation)
 

silverpig

Lifer
Jul 29, 2001
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Originally posted by: Eeezee
I already knew that aspect, I just misread the article - it was a PHOTON scattering off of the atom (not an electron, which is what I thought they originally meant - that they were taking a picture of the scattered electron by watching the oscillation)
They are detecting the electron...

Each experiment generated a "bullseye" pattern showing the locations in which electrons struck the detector plate.
I think the experiment runs like so:

They use an IR laser to make electrons oscillate in a helium atom. They then use a short laser pulse from a second laser to rip the electrons off the atom. The electron then feels a weak applied electric field and drifts towards a detector where the image is generated. The rings seen are a diffraction pattern (I think... I still haven't read the paper). They can vary the timing between the two lasers to change at what point in the IR driven oscillation the short pulse laser rips the electron off.
 

RESmonkey

Diamond Member
May 6, 2007
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I doubt it but....

it caaann be possible (maybe). Not a picture picture in the sense, but you can try to figure out what kind of shape it is? Hit the whole are with photos, keep doing it from all directions/energy ranges. Get a massive supercomputer and get it to calculate a 3d solution of the object encountered. yes, I know it will change everytime a photon hits it. That's why you try to counteract this change mathemetically estimated per every photon. I dunno if there is a supercomputer that intense, but eh.

 

randay

Lifer
May 30, 2006
11,019
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Nothing is impossible! Not when you can imagine it! Thats what science is all about!
 

RESmonkey

Diamond Member
May 6, 2007
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Somehow, Yahoo confirming it doesn't mean anything to me. Is there an actual/reliable source? A University/physics site, at least?
 

Braznor

Diamond Member
Oct 9, 2005
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Quoting the article :

The filmed sequence shows the energy distribution of the electron and is therefore not a film in the usual sense.
 
Mar 10, 2005
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Originally posted by: Braznor
Quoting the article :

The filmed sequence shows the energy distribution of the electron and is therefore not a film in the usual sense.
so that's basically saying "we filmed the wake of a boat, but no boat."

what element is that supposed to be, anyway? something heavy, with all those orbits. or are those one orbit with motion blur? why is there no orbit visible across the middle?
 

Bill Brasky

Diamond Member
May 18, 2006
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Dunno if this helps any, but I found it interesting.

"Accumulating data from many ionization events, the team created clean images of the quantum state of electrons ionized at a single moment in the laser oscillation cycle. The images are the first of their kind that show such controlled electron-atom scattering. The team calls their system a stroboscope, after another device that uses periodic flashes of light to capture a still image of a hummingbird's wings, for example.

Each experiment generated a "bullseye" pattern showing the locations in which electrons struck the detector plate. To demonstrate that each image represented precisely one moment during the laser cycle--rather than , the pattern shifted upward; if the ionizing pulse came a half-cycle later, the bullseye shifted downward. This pattern shifting wouldn't have been possible with longer-lasting ionization periods.a range of ionization times--the team shifted the timing of the attosecond pulses with respect to the laser field cycle. If electrons were ionized at a time when the laser field gave them an extra boost upward"
 
Mar 10, 2005
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so the video isn't 1 contiuous shot, it's dozens of separate events at different phases of the laser wavelength. the laser ionizes the atom, and the free electron is steered into the detector. the detector spits out a bullseye picture of ??? and measuring the quantum state changes it.

not an electron. not even a video :confused:
 

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