Quantum teleportation performed with light from a quantum dot embedded in an LED

Mar 15, 2013 by Lisa Zyga feature
Experimental set-up of the quantum teleportation device including an entangled light-emitting diode (ELED) and an assortment of beam splitters polarization controllers, detectors, and photodiodes. The researchers demonstrated that the device can generate single pairs of entangled photons with advantages compared with using a laser due to the electrical control provided by the ELED. Credit: J. Nilsson, et al. ©2013 Macmillan Publishers Limited. All rights reserved.

(Phys.org) —In a new study, physicists have teleported photonic qubits made of pairs of entangled photons that are generated by an LED containing an embedded quantum dot. The novel set-up has advantages compared to the conventional method of generating entangled photons using a laser, and could lead to a simplified technique for implementing quantum teleportation in quantum information applications.

The researchers, J. Nilsson, et al., at Toshiba Research Europe Limited and the University of Cambridge, both in Cambridge, UK, have published their paper on demonstrating using an LED in a recent issue of Nature Photonics.

As the scientists explain, quantum teleportation—a process in which quantum information is destroyed so that it may be transferred simultaneously to another location—has been proposed as a way to create quantum and protocols despite the no-cloning theorem. According to the no-cloning theorem, quantum information cannot be copied. Although no-cloning enables to have a high degree of security, it also limits the options to create quantum communication networks and increases the losses in quantum computing due to imperfect measurements.

Teleporting the information may offer a solution for these two areas. In networks, teleportation can establish a between two nodes. In quantum computing, teleportation can transfer qubits from successful , while the other qubits can be thrown out. Although quantum teleportation can be implemented with different systems, the researchers here argue that photonic qubits are best suited for the largest number of applications.

One of the most important parts of the photonic teleportation process is having a that produces single pairs of . Although lasers can be used to generate the photons, they involve practical complexities and sometimes generate multiple photon pairs, and these problems have inhibited their use in quantum information technologies.

"We can also produce entangled photon pairs by pumping a non-linear crystal with a laser," coauthor Andrew Shields at Toshiba Research Europe Limited told Phys.org. "Although this has facilitated many experiments in quantum optics in the past, it has the disadvantage that the process sometimes produces two (or more) pairs. These multiple pairs cause errors in quantum information processing schemes that become increasingly problematic as we scale to larger numbers of photons. Thus developing true quantum light sources (i.e., one that produces just one entangled pair at a time) is seen as essential to achieving useful applications in quantum communications and photonic quantum computing."

As an alternative, the researchers here created an entangled-light-emitting diode (ELED) with an indium arsenide quantum dot to generate pairs of entangled photons one at a time. Using the ELEDs, the researchers demonstrated an average teleportation fidelity that exceeds the maximum that can be achieved using only classical correlations, proving the quantum nature of the teleportation. A key difference with this set-up compared with laser-based set-ups is that here the photons are generated electrically rather than optically. One benefit of electric generation is that the emission wavelength of the quantum dot can be easily tuned using electric fields, which could make it compatible with a wide range of input photons of different wavelengths.

"It is actually quite straightforward to embed a quantum dot in an LED," Shields said. "The quantum dot is formed by a self-organizing method during the growth of the semiconductor layers. The quantum dot is comprised of indium arsenide, which has a larger lattice constant than the gallium arsenide substrate. This results in a very thin layer (about 2 monolayers thick) self-assembling into quantum dots. After growing the rest of semiconductor structure, we are left with a layer of quantum dots embedded inside the LED."

The researchers hope that the ability of the ELEDs to generate single pairs of entangled photons, along with future improvements in light collection efficiency and entanglement fidelity, will lead to the realization of a variety of teleportation-based quantum information applications.

"Quantum teleportation is an important primitive in processing," Shields said. "We are planning to apply it to quantum communications and deterministic photonic quantum logic gates."

Explore further: Physicists discuss quantum pigeonhole principle

More information: J. Nilsson, et al. "Quantum teleportation using a light-emitting diode." Nature Photonics. DOI: 10.1038/NPHOTON.2013.10

Journal reference: Nature Photonics search and more info website

4.5 /5 (27 votes)

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G_ Budai
2.3 / 5 (3) Mar 15, 2013
Damn..the worst feeling was the lack of knowledge in comprehending telecom, informatics. 01000110 01001001 01001110 01000001 01001100 01011001, after learned all that staff, now U R arriving with quantum cryptography...
baudrunner
3.4 / 5 (5) Mar 15, 2013
Like graduating with a computer programming diploma just as the days of DOS are drawing to a close.
johanfprins
1.8 / 5 (5) Mar 16, 2013
Great work!!

I hope it is dawning on the mainstream scientific community that the total energy of a SINGLE coherent light wave is determined by the emitter, and that the lowest amount of energy that can be emitted by an emitter is that of a quantum of EM-energy!

Thus, the so-called entangled "double-photon" wave does NOT consist of two separate photons but is a SINGLE wave with distributed EM-energy: No "wave-particle" Voodoo is involved!

Only when a measurement is made that disentangles the wave, are two separate photons obtained. While the wave stays entangled, it can also be forced to split in two sub-parts which are NOT separate photons. This also happens when a SINGLE photon-wave moves SIMULTANEOUSLY through two slits. No Voodoo "which-way" information is involved.
Freemove
2.3 / 5 (3) Mar 16, 2013
Another step towards quantum repeaters.

Note that Information-Theoretic True Quantum Randomness secured Communication and Storage is already operational since 2007, see eg. wuala.com/FreemoveQuantumExchange
Lurker2358
4 / 5 (4) Mar 16, 2013
Just remember, "impossible to intercept" communications works for the bad guys too, whether terrorists or rogue states.

You will no longer be able to spy on the enemy spies. You will no longer be able to spy on the terrorists to prevent their evil.
tkjtkj
3 / 5 (2) Mar 16, 2013
"Although lasers can be used to generate the photons, they involve practical complexities and sometimes generate multiple photon pairs, and these problems have inhibited their use in quantum information technologies"

http://phys.org/n...tml#nwlt


Gee, in all the yrs of discussions here involving entanglement I cant recall a single mentioning of where generation fails! .. so here i am in my imaginary world of perfection .. now destroyed by a simple revelation .. 'bad things cAN happen!' .. and do!

LeatheryObject
1 / 5 (1) Mar 16, 2013
Just remember, "impossible to intercept" communications works for the bad guys too, whether terrorists or rogue states.

You will no longer be able to spy on the enemy spies. You will no longer be able to spy on the terrorists to prevent their evil.


"Evil" is not as black and white as you may want to believe
kochevnik
1 / 5 (5) Mar 16, 2013
Just remember, "impossible to intercept" communications works for the bad guys too, whether terrorists or rogue states.

You will no longer be able to spy on the enemy spies. You will no longer be able to spy on the terrorists to prevent their evil.
One man's terrorist is another man's freedom fighter. Of course the Islamic jihad is nothing more than a movement to establish a theocracy. A cause to which YOU are sympathetic, Lurker2358
"Evil" is not as black and white as you may want to believe
Abrahamic religions all originated from Rome, and thus employ Caesar's tactic of "divide and conquer" using Hegelian dialetics
Lurker2358
3.4 / 5 (5) Mar 17, 2013
Of course the Islamic jihad is nothing more than a movement to establish a theocracy. A cause to which YOU are sympathetic, Lurker2358


If I knew, I'd sue you for that. It's slandar/libel, and is absolutely not true at all.

I hate Islam, and I wish it would disappear today.

It won't though. It would be highly practical if we could just execute all the adult male Muslims, but then that starts to be about as bad as they are.

They are apparently unteachable, so I suppose that if the rest of the world isn't going to eliminate them, then this idiotic cycle that's been going on for the past 1300 years is just going to go on for as long as the planet is here; which has got to be a greater evil than the "evil" that would be done by killing them all now and saving future generations the trouble.

See, that's the moral problem here; eliminating Islam requires everyone else to become nearly as evil as they are. Though at some point "pre-emption" is not neccesarily evil, it's just smart
johanfprins
3 / 5 (4) Mar 17, 2013
All man-made institutions eventually produce zealots who at some stage in the history of that institution control the institution, or large parts of the institution. Organized religions ALL have a bad track-record: But it is not just organized religions; also, as at present, organized science.

For example, the Royal Society of London is not the same as it was intended to remain: It has betrayed the ideals of its founding fathers to such an extent, that most of them are similar to the Muslim's who believe in Jihad; or the Christians who believed in the Crusades, etc. Similar for the AAAS who in typical Orwellian-style claim that they "advance science" but is censoring all scientific ideas which could lead to the paradigm shifts that our planet are in dire need of.

What is unfortunate is that the people within these dysfunctional organizations, who are not hair-brained zealots, allow the extremists to rule the roost; and to pull our planet down with them!
kochevnik
1 / 5 (3) Mar 17, 2013
Of course the Islamic jihad is nothing more than a movement to establish a theocracy. A cause to which YOU are sympathetic, Lurker2358


If I knew, I'd sue you for that. It's slandar/libel, and is absolutely not true at all.

I hate Islam, and I wish it would disappear today.
You only prove what I wrote. Your stupid Abrahamic religions are based upon nothing more than hatred. All of you morons should be put into a pen and only one allowed to leave. The winner can become the new Nazi pope

But thanks for your interest in suing me. I'm sure you would make an excellent case in a Moscow courtroom. Maybe you will be charged with a mysterious arson incident during your stay and you can get Pussy Riot back together behind bars!
TheGhostofOtto1923
1.7 / 5 (6) Mar 17, 2013
If I knew, I'd sue you for that. It's slandar/libel, and is absolutely not true at all.

I hate Islam, and I wish it would disappear today.
Right. Because as we all know, yours is the good religion, at least according to Bosnian serbs.

But Koch is right isn't he, that you would want to live under a theocracy? What is slanderous about assuming that? In god you trust, correct?
But thanks for your interest in suing me. I'm sure you would make an excellent case in a Moscow courtroom
Careful. Look what happened to pussy riot.
Whydening Gyre
1.8 / 5 (5) Mar 17, 2013
One man's "evil" is another man's playground. The only true "evil" is done by those who allow/manipulate it to do harm for excessive personal gain(ie - huge gobs of money).
Back to the article - I wish they would stop using "teleportation" as a term. It's not instantaneous - it's just travelling at a rate of speed even faster than light. Sort of like the speed of light relative to the speed of sound, but we just haven't figured out how to measure it, yet.
We live in a Universe of "wave/particle" combo's that combine to make other waves, which combine to make even MORE waves, and so on. THere is no such thing as a single particle of anything - just parsed segments of something else. Seems like a fairly obvious observation...
"Voodoo" is the perceptual stance (POV) taken by those who can only perceive limits on anything. Sorry, but it's a basic rule of the Universe we exist in - deal with it.
Bring back analogue Hi-Fi audio!
Jack Heart
1 / 5 (1) Mar 19, 2013
@johanfprins I just joined this site and you guys are the scientists so I will just read and learn but I just have to second your thoughts on sanctioned institutions roll in preserving stupidity in academia. For anyone who wants a detailed and documented account of just how badly they have distorted human history, particularly that of America, they can Google jackheart and read my Skinwalker posts. After a nine month intensive study of the facts my conclusion is that it is no accident and cannot be chalked up simply to blind belief in rhetorical dogma. There is something much more insidious at work there.
johanfprins
3 / 5 (2) Mar 19, 2013
@ Jack Heart
After a nine month intensive study of the facts my conclusion is that it is no accident and cannot be chalked up simply to blind belief in rhetorical dogma. There is something much more insidious at work there.


If I look at my experiences during the last decade I tend to agree with you. It just cannot be overall stupidity and mediocrity that cause mainstream scientists to consistently censor any new data and logic which have the potential to prove accepted dogma, especially in the fields that rely on quantum field theory, wrong.

For example, from the Proc. of the Royal, a manuscript of mine was rejected because I proved impeccably that the BCS model cannot explain why the electric field between two contacts must go to zero when superconduction occurs. The rejection read: "I am not an expert but will be surprised if the BCS model cannot model this. He is not an "expert" but "expert" enough to veto a manuscript since he will be "surprised"! God help mankind!
johanfprins
1 / 5 (1) Mar 19, 2013
Sorry! Withdrawn!