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Chilly chip achieves important quantum computing advance

University of California Santa Barbara Physics professor John Martinis is looking to trap sunshine in a bottle; or photons in a cavity, more precisely.  His former postdoctoral fellow Yi Yin -- now a professor at Zhejiang University in the city of Hangzhou, China -- has just published a work in the journal Phys. Rev. Letters detailing how her team used tiny superconducting structures to selectively trap and release photons.

Ms. Yin comments, "As one crucial step of achieving controllable quantum devices, we have developed an unprecedented level of manipulating light on a superconducting chip.  In our experiment, we caught and released photons in and from a superconducting cavity by incorporating a superconducting switch.  By controlling the switch on and off, we were able to open and close a door between the confined cavity and the road where photons can transmit. The on/off speed should be fast enough with a tuning time much shorter than the photon lifetime of the cavity."

The study uses a two-atom construct for the "qubit" (quantum bit) that stores the photon state information in the Fabry-Perot cavity.  The team uses a switchable mirror to act like a shutter, controlling the waveform of the released photons.

UCSB quantum chip
The UCSB superconducting quantum chip was chilled to three-hundreths of a degree Kelvin.

There were some rather significant technical hurdles that are required to achieve the team's impressive results.  The approximately 1 sq. inch chip had to be chilled to -273.12 ºC -- or about two-hundredths of a degree Kelvin above absolute zero.

The next step is to tune the device to transfer controlled-state photons between two cavities.  That will be a critical step towards quantum memory or a cavity-based quantum computing device.

Sources: UCSB, Phys. Rev. Letters

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0.02 or 0.03 K?
By XZerg on 3/5/2013 1:08:22 PM , Rating: 2
Under the image it says 0.03K and in the last 2nd para it says 0.02K, don't mind the short forms.

regardless, this sounds interesting.

RE: 0.02 or 0.03 K?
By gmyx on 3/5/2013 1:57:35 PM , Rating: 2
The article states it was chilled to -273.12 ºC. That is .03ºk off of absolute zero.

RE: 0.02 or 0.03 K?
By MozeeToby on 3/5/2013 3:10:32 PM , Rating: 5
Just .03K. Capital K, no 'º'. It's capital because it's named after a person: William Thomson, 1st Baron Kelvin. You drop the º because unlike degrees C or F, Kelvins are a direct measurement of the thermal energy of a system (something that is 20 ºC cannot be said to be 2 times warmer than something that is 10 ºC). Basically, the º calls out that the scale is arbitrary, which isn't the case for Ks.

RE: 0.02 or 0.03 K?
By MadMan007 on 3/5/13, Rating: -1
RE: 0.02 or 0.03 K?
By inighthawki on 3/5/2013 3:33:34 PM , Rating: 3
A terrible thing when someone nicely explains something for the rest of the world to learn from and gets met with sarcasm.

RE: 0.02 or 0.03 K?
By MadMan007 on 3/5/13, Rating: 0
RE: 0.02 or 0.03 K?
By ZmaxDP on 3/5/2013 9:16:59 PM , Rating: 3
It's sad when accuracy is confused with being nit-picky. Personally, I like it when someone "goes on" to explain why something isn't used instead of just correcting it's misuse.

RE: 0.02 or 0.03 K?
By inighthawki on 3/6/2013 3:32:24 PM , Rating: 2
My fault? Your post screams sarcasm. I guarantee 99% of people read your post as an insult, the equivalent of the common sarcastic insult, "thanks captain obvious"

Correct me if i a wrong
By Ammohunt on 3/5/2013 2:32:02 PM , Rating: 2
But isn't this akin to perpetual motion machines? Energy is not lost in this transaction?

RE: Correct me if i a wrong
By MozeeToby on 3/5/2013 3:17:06 PM , Rating: 3
Perpetual motion, by itself, is fine, it's extracting energy from a system that is in perpetual motion that isn't. Two black holes orbiting around each other in empty space will be stable for the lifetime of the universe (though even there, some energy is extracted in the form of gravity waves... well, according to theory anyway).

Imagine a loop of fiber optics that was efficient enough and long enough that you could connect and disconnect the ends before a signal made it all the way around. You could trap the light inside making loops and if fiber were optically perfect you could store the light that way. What they've done is found a way to connect up the ends of a loop (actually a cavity, but same thing in principle) so fast that the loop can be microscopic.

RE: Correct me if i a wrong
By MadMan007 on 3/5/2013 3:30:55 PM , Rating: 2
The photon has to come from somewhere.

OT: I have to ask
By Touche on 3/5/2013 2:23:14 PM , Rating: 2
Sorry for the OT, but I've been wondering what is it with the use of commas in headlines on this site? Why are "and" or "&" avoided? Most of the time it feels really unnatural to read headlines and interpret what was meant to be said. Is it a standard practice in US?

RE: OT: I have to ask
By MozeeToby on 3/5/2013 3:02:18 PM , Rating: 2
It has been standard practice in print for a long time (probably more than a century) to save space in headlines. Seems kind of silly on a website to me, but it makes it appear more professional or "news-y" to some people.

By drycrust3 on 3/5/2013 2:05:52 PM , Rating: 2
That will be a critical step towards quantum memory or a cavity-based quantum computing device.

The interesting thing about photons is they are what transfers energy from one atom to another, and are always present at temperatures above absolute zero. It will be interesting to see how long they can keep their "trained" photons separate from the "untrained" rabble.
Another interesting thought is since the wavelength of the photon is inversely proportional to the energy content, then maybe the treatment given to a photon can be changed depending on its energy content, e.g. the high energy content photons could be "refracted" along a different path to those of low energy content.

Wonders of Science
By mars2k on 3/6/2013 9:04:54 AM , Rating: 2
Does this mean that I will be able to store my porn in my freezer soon?

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