A quantum low pass for photons

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A quantum low pass for photons

Post by Cr6 on Sun May 21, 2017 8:41 pm

A quantum low pass for photons

Date:
   April 13, 2017
Source:
   Max Planck Institute of Quantum Optics
Summary:
   Physicists have observed a novel quantum effect that limits the number of emitted photons, outlines a new report.

https://www.sciencedaily.com/releases/2017/05/170508112406.htm



Illustration of the two-photon blockade. Top: Irradiated by a laser pulse a single atom in free space can absorb and emit only one photon at a time, without constraints on the direction of the photons. Middle: A system consisting of a cavity can absorb and emit an unlimited number of photons. Below: In case of the strongly coupled atom-cavity system the frequency of the laser light can be chosen such that the system can store and emit two photons at maximum.
Credit: MPQ, Quantum Dynamics Division


Last edited by Cr6 on Sun May 21, 2017 8:44 pm; edited 1 time in total

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Re: A quantum low pass for photons

Post by Cr6 on Sun May 21, 2017 8:43 pm

Unpolarized single-photon generation with true randomness from diamond

Date:
May 8, 2017
Source:
Tohoku University
Summary:
Scientists have demonstrated dynamically and statically unpolarized single-photon generation using diamond.



Schematic picture of unpolarized single-photon generation using a compound defect, a nitrogen vacancy center (NV center), in a diamond. Spheres, designated N and V respectively, indicate a nitrogen atom and a vacancy which comprises an NV center in the diamond lattice. Dynamically and statically unpolarized single-photon emission is induced by laser excitation for a [111]-oriented NV center in (111) diamond.
Credit: Naofumi Abe

The Tohoku University research group of Professor Keiichi Edamatsu and Postdoctoral fellow Naofumi Abe has demonstrated dynamically and statically unpolarized single-photon generation using diamond. This result is expected to play a crucial role in hardware random number generation using single photons (quantum dice or quantum coin toss), quantum cryptography and the testing of fundamental problems in quantum mechanics.


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Re: A quantum low pass for photons

Post by Cr6 on Sun May 21, 2017 8:47 pm

Researchers transmit 10 bit of information with a single photon

Date:
February 3, 2017
Source:
University of Twente
Summary:
Researchers have managed to transmit more than 10 bit of information with a single photon. They achieved this using an ingenious method for detecting individual photons. The knowledge gained from this study can be used to improve the security and speed of quantum communication.

https://www.sciencedaily.com/releases/2017/02/170203102740.htm

Researchers at the University of Twente's MESA+ research institute have managed to transmit more than 10 bit of information with a single photon. They achieved this using an ingenious method for detecting individual photons. The knowledge gained from this study can be used to improve the security and speed of quantum communication. The research results were published in the scientific journal Optics Express.

When asked "How much information can you transmit using just a single photon?" most scientists would answer 'one bit' (either a '1' or a '0'). In theory, however, there is no limit to the amount of information you can transmit with a single photon. There are, however, many practical considerations that limit the amount of information per photon. Using an innovative method, University of Twente researchers have now managed to transmit no less than 10.5 bits of information with a single particle of light.

Method

Prof. Pepijn Pinkse, one of the researchers involved, explains how the system works. "You can compare it to shining a laser pointer onto letters mounted on a groove board. The illuminated letter is the information contained in the laser pointer's light. The number of letters on the groove board determines the amount of information you can transmit with the light." The main difference is that Prof. Pinkse and his team created an alphabet of 9072 characters, and they -- unlike the laser pointer in the analogy above -- transmitted the information with a single photon. That was the key challenge in this study: single photon detection. This is because noise (random photons) can impede measurement. The researchers devised a clever ruse to eliminate any noise. They exploited the fact that individual blue photons can split into exactly two red photons. The researchers arranged for the first photon to send a signal to the detector (which is comparable to a digital camera), which then opened up very briefly. Using a mirror, the second photon was directed at the desired letter of the specially created alphabet. However, they forced this photon to make a slight detour, so that it arrived at the target letter at exactly the same time as the detector opened up. That was the only instant at which photons were able to pass into the detector. In this way, the researchers were able to eliminate noise.

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Two Out of Three Ain't bad

Post by LongtimeAirman on Mon May 22, 2017 12:13 pm

.
Hey Cr6, Thanks, I enjoyed A quantum low pass for photons and Unpolarized single-photon generation with true randomness from diamond.

But then I started reading the third article, Researchers transmit 10 bit of information with a single photon:
"ingenious method for detecting individual photons."
"10.5 bit of information with a single photon."
"In theory, however, there is no limit to the amount of information you can transmit with a single  photon."
The researchers devised a clever ruse to eliminate any noise. They exploited the fact that individual blue photons can split into exactly two red photons".

Each claim in this particular article is absurd and/or ridiculous. Fake news is now part of our reality; that includes fake science too. Please correct me if you see otherwise.
.

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Re: A quantum low pass for photons

Post by Nevyn on Mon May 22, 2017 6:16 pm

I especially liked the 10.5 bits. What the hell is 0.5 of a binary digit? Do they not even understand number systems anymore?
And the lack of a theoretical limit on the amount of information you can transfer in a single photon. That just tells me they have no theory regarding what photons are and how they work. I'd still like to hear the details though. I assume they have transferred information, just not in the way they think they have.
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Re: A quantum low pass for photons

Post by Cr6 on Sat May 27, 2017 1:13 am

We got to get a patent out there for the real Charge Field... each encyrpted/patented photon = 1 $USD.

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