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Caltech Scientists Film Photons With Electrons
al0ha writes "Techniques recently invented by researchers at the California Institute of Technology which allow the real-time, real-space visualization of fleeting changes in the structure of nanoscale matter have been used to image the evanescent electrical fields produced by the interaction of electrons and photons, and to track changes in atomic-scale structures."
This is actually quite applicable to quantum computing. We are getting to the point where we can define the qubits, but have trouble measuring the photon emissions that indicate the result of the computation. This will allow us to finally measure what amounts to the result of the quantum calculation. It's been a long time in coming, but this will finally allow us to make some significant strides towards commercializing quantum computing.
I didn't see that coming.
(C'mon! It's funny! Photons! Femtoseconds! Ahh.. fergetaboutit.)
There are two tiny pictures there, but no videos, and no links other than to another press release which also doesn't have videos.
Am I just not looking hard enough?
Don't thank God, thank a doctor!
http://en.wikipedia.org/wiki/Photoelectric_effect
instead of going from photon to electron then presumably back to photon so human eyes can see it, why not skip the conversion for increased efficiency? plus i have no idea how to cast/convert these data structures...
and you're using a very high resolution camera.
Film photons with electrons, and its another confusing /. title.
I own a camera you see.
These posts express my own personal views, not those of my employer
I'd say this is no big deal...
It's Friday, I'm drunk, but what the FUCK?! I can't grasp..
Fuck. CalTech. Guess them nerds do know what they're doing.
I met nerds from CalTech and MIT. MIT nerds got nothing on CalTech nerds. When it comes to physics, I'd go with CalTech nerds. p. The nerd from my Ivy League school just don't measure up, including me...
Fuck systemd. Fuck Redhat. Fuck Soylent, too. Wait, scratch the last one.
This article needs a "Schroedinger" tag. :)
"Exclusive photos of photons caught mingling with electrons", "Quantum sex scandal!", "Proton threatens divorce, electron believed gone after excitement with photon"
My webcomic
If we image things with photons, we call it a photo. Since they imaged the photons with electrons, should their image then called an electro?
The Tao of math: The numbers you can count are not the real numbers.
That his head exploded. He apparently looked at he picture, said "Wow, now I understand how a photo is simultaneously can be a wave and a particle" and then when his brain tried to rectify that paradox his head blew up. Services are at 10am on Tuesday.
Did you know 80 to 90% of the moderators on slashdot wouldn't recognize a troll even if one dragged them under a bridge.
Can be seen here: http://ust.caltech.edu/movie_gallery/#paper3
The photo-electric effect is when electrons are released from a material when they absorb energy from photons. When the energy of the photons isn't above the threshold energy of the material, you get nothing. Also the energy of the emitted electrons doesn't depend on the intensity of the light.
This new technique called PINEM (photon-induced near-field electron microscopy), is used to image the "glow" (i.e., photon emissions) that is emitted by objects that have been excited by femto-second laser pulses using short pulses of electron beams. The image of the object glow is formed by measuring the energy of the scatterred short electron beam.
So in PINEM we are measuring a photons field using an electron pulse in a way where the electrons have a scatter function and different electron energies (think of this as an "analog" 4-d picture of the photon field), in the PE-effect, we are getting some number of electrons of a fixed energy which we can count (think of this like a "geiger counter" measurement of the incident photon field on the material).
Also since you are measuring a field and not the material, in the PE-effect, the material has to absorb the photon and emit (non-coherently) at it's electron work function energy. If the absorbtion ability and/or the energy disparity beween the photons and the work function is large, PE-effect doesn't even give you anything.
As a not very good analogy to think about, with PINEM, you can effectively take a "flash" picture (the flash is the femto-second laser pulse) of the photon emmission field which doesn't disturb the material that much. With any imaging technique that tried to use the PE effect, you'd have to illumiate the material with a photon field (over time and with different intensities) which wouldn't allow you to see anything. This would be like taking a picture with no shutter over a long period of time and imaging them with a binary threshold (kinda-like how old fax machines scanned pictures before dithering). Very blurry (because of the time averaging of the illumiation to get electrons emitted), and very uninteresting (because of the single energy level, uncorrelated nature of the electron emmission from the PE-effect). As another silly analogy, PE-effect is like hearing the alarm of water going above a dam, where PINEM is like looking at the a 3-d movie of the water-level behind the dam even if the water level didn't go above the dam.
Saying this is "old news" is like saying that the transistor was old news, because we discovered lightning a long time ago. ;^)
As I understand the article, this technology works as follows: a short laser pulse excites the electrons of a sample material. After a short delay t, a short electron pulse hits the sample. The diffraction of the electron pulse is used to generate a picture of the electronic states in the sample at the time t after the excitation by the laser pulse. This is repeated several times, with different delays t. By combining these images, they can see how the electronic states develop over time. It is a combination of pump probe spectroscopy and electron microscopy, very interesting that this is possible. However the state of the electrons excited by the laser is destroyed every time an electron pulse hits the sample. You can only see the time development of electronic states by repeating the complete experiment, which is not what you want for a quantum computer. I think this is a fundamental principle of quantum mechanics described by Heisenberg's uncertainty equation. However this is not my field, and I don't know much about the details of quantum computing. Maybe this technology can help to understand what happens in a quantum computer though.