Quantum Entanglement Links Two Diamonds

[Drone]

This is so kewl. Here's why:

A group of researchers report in the December 2 issue of Science that they managed to entangle the quantum states of two diamonds separated by 15cm.

For those who forgot or don't know what quantum entanglement is:

Quantum entanglement is a phenomenon by which two or more objects share an unseen link bridging the space between them—a hypothetical pair of entangled dice, for instance, would always land on matching numbers, even if they were rolled in different places simultaneously.

But ...

But that link is fragile, and it can be disrupted by any number of outside influences. For that reason entanglement experiments on physical systems usually take place in highly controlled laboratory setups—entangling, say, a pair of isolated atoms cooled to nearly absolute zero.

But not this time. They managed to achieve this in macroscopic objects at room temperature! They used two squares of synthetically produced diamond, each 3mm across and a laser pulse, bisected by a beam splitter, passing through the diamonds and a photon detector. A phonon which was generated in the process helped them to realize that entanglement did actually happen. Even though the process didn't last long (only few picoseconds) they ran experiment over and over again to gather statistically significant results which made them conclude with confidence that entanglement had indeed been achieved.



So here's what they did:

To entangle relatively large objects, researchers harnessed a collective property of diamonds: the vibrational state of their crystal lattices. By targeting a diamond with an optical pulse, the researchers can induce a vibration in the diamond, creating an excitation called a phonon—a quantum of vibrational energy. Researchers can tell when a diamond contains a phonon by checking the light of the pulse as it exits. Because the pulse has deposited a tiny bit of its energy in the crystal, one of the outbound photons is of lower energy, and hence longer wavelength, than the photons of the incoming pulse.

To verify the process they did this:

To verify the presence of entanglement, the researchers carried out a test to check that the diamonds were not acting independently. In the absence of entanglement, after all, half the laser pulses could set the left-hand diamond vibrating and the other half could act on the right-hand diamond, with no quantum correlation between the two objects. If that were the case, then the phonon would be fully confined to one diamond.

If, on the other hand, the phonon were indeed shared by the two entangled diamonds, then any detectable effect of the phonon could bear the imprint of both objects. So the researchers fired a second optical pulse into the diamonds, with the intent of de-exciting the vibration and producing a signal photon that indicates that the phonon has been removed from the system. The phonon's vibrational energy gives the optical pulse a boost, producing a photon with higher energy, or shorter wavelength, than the incoming photons and eliminating the phonon in the process.

Oxford and NUS physicist Vlatko Vedral, who was not involved in the new research, says:

It "beautifully illustrates" the point of Austrian physicist Erwin Schrödinger's famous thought experiment in which a hypothetical cat is simultaneously alive and dead. It can't be that entanglement exists at the micro level (say of photons) but not at the macro level (say of diamonds), because those worlds interact. Schrödinger used atoms instead of photons and cats instead of diamonds, but the point is the same.

So here we have it, quantum laws in everyday life. I found this article @ Scientific American

http://www.scientificamerican.com/ar...e-entanglement



Other interesting articles from SA:

http://www.scientificamerican.com/ar...n-entanglement
http://www.scientificamerican.com/ar...-quantum-world

[theJesus]

http://www.techpowerup.com/156101/R-...st-Friend.html

[Drone]

^ So what? Anywho ..


Now entanglement can be generated, manipulated and measured. This time it's not diamonds, it's a chip. So programmable quantum processors will be real someday.

The fundamental resource that drives a quantum computer is entanglement—the connection between two distant particles which Einstein famously called 'spooky action at a distance'. The Bristol researchers have, for the first time, shown that this remarkable phenomenon can be generated, manipulated and measured entirely on a tiny silica chip.

"In order to build a quantum computer, we not only need to be able to control complex phenomena such as entanglement and mixture, but we need to be able to do this on a chip, so that we can scalably and practically duplicate many such miniature circuits—in much the same way as the modern computers we have today," says Professor Jeremy O'Brien, Director of the Centre for Quantum Photonics.

The pic above:

The chip consists of a network of tiny channels which guide, manipulate and interact single photons. Using eight reconfigurable electrodes embedded in the circuit, photon pairs can be manipulated and entangled, producing any possible entangled state of two photons or any mixed state of one photon.

Nice news. They've been working on this for the past six years. Developing quantum photonic chips ain't an easy task I suppose.

Dr Terry Rudolph from Imperial College in London, UK, believes this work is a significant advance. He said: "Being able to generate, manipulate and measure entanglement on a chip is an awesome achievement. Not only is it a key step towards the many quantum technologies— such as optical quantum computing—which are going to revolutionize our lives, it gives us much more opportunity to explore and play with some of the very weird quantum phenomena we still struggle to wrap our minds around. They have made it so easy to dial up in seconds an experiment that used to take us months, that I'm wondering if even I can run my own experiment now!"

Yay!

http://www.physorg.com/news/2011-12-...grammable.html

[W1zzard]

Originally Posted by Drone

Quantum entanglement is a phenomenon by which two or more objects share an unseen link bridging the space between them%u2014a hypothetical pair of entangled dice, for instance, would always land on matching numbers, even if they were rolled in different places simultaneously.

an easier explanation in (my opinion) is:

- you have two magic boxes, each with a black or white ball inside.
- the magic boxes are linked.
- when you open one and get a black ball, the other is guaranteed to have a white ball. and vice versa

either way. it can't be used for ftl information transfer

[Drone]

Originally Posted by W1zzard

- when you open one and get a black ball, the other is guaranteed to have a white ball. and vice versa

Yup that too. So quantum computers can have logical NOT operator (negation) "for free" without spending a single cycle on it which is awesome. Because of this the orthogonalization / normalization of matrices and any other calculations can be performed much faster. I bet with quantum computers programmers would need totally different kind of logic because this kind of computing would require a different approach

[3volvedcombat]

Originally Posted by W1zzard

an easier explanation in (my opinion) is:

- you have two magic boxes, each with a black or white ball inside.
- the magic boxes are linked.
- when you open one and get a black ball, the other is guaranteed to have a white ball. and vice versa

either way. it can't be used for ftl information transfer

Someone Should Seriously Be a Professor. A teacher, Something ^^^^^^

[Drone]

More news about entangled diamonds:

The researchers, from Oxford University, National University of Singapore, and National Research Council of Canada, also sought to exploit another property of diamond: it tends to scatter light in such a way that a photon striking it can be converted to a lower energy photon, with the remaining energy being converted into a vibration.

Diamonds are entangled with one vibration shared between them! This vibration in diamond can be detected using a laser. Researchers sent bursts of laser through both diamonds:

Most of the time the light would travel straight through the crystals but sometimes the light would dump some energy in one of the crystals, setting it ringing, and the light would then emerge with less energy - a lower frequency. The light is combined after the crystals so that when a low frequency pulse is detected, it is possible for scientists to know that one diamond is vibrating, but not which one.

‘In fact, the universe doesn't know which diamond is vibrating!’ one of the researchers explains. They think about practical application for this work in the future such as encryption:

Another possibility is explored in a related piece of work using these diamonds that makes use of the quantum character of "nothingness". It exploits this possibility to generate truly random numbers

http://www.physorg.com/news/2011-12-...-diamonds.html

[qubit]

You might want to read this together with the news article that I posted a couple of weeks ago. Drone, you've obviously put a lot of effort into your posts here to give us something of quality to read and I think that's really cool.

Power to the qubit!

Mods, I request that you do not close or merge this thread, as I think the two complement each other.

[Drone]

Originally Posted by qubit

Mods, I request that you do not close or merge this thread, as I think the two complement each other.

Yes I don't want to get this topic put in news because all the threads in the News forums will get buried pretty soon. While in Science & Technology it's easiser to navigate and "pile up" all interesting ideas and findings.

[The_Ish]

Originally Posted by W1zzard

an easier explanation in (my opinion) is:

- you have two magic boxes, each with a black or white ball inside.
- the magic boxes are linked.
- when you open one and get a black ball, the other is guaranteed to have a white ball. and vice versa

either way. it can't be used for ftl information transfer

So how is it guaranteed to have the opposite color if it's EITHER a black or white?

[Drone]

Totally unrelated but I want to post this amazing video made by JAPAN INSTITUTE OF SCIENCE AND TECHNOLOGY here because it's awesome



It's called Quantum levitation. It's awesome what magnetic field, electric current and Lorentz force can do! They use liquid nitrogen for cooling.

If only superconductivity wouldn't need that brutal cooling this technology could be used for real transportation! Maybe somewhen somewhere ...

[qubit]

Originally Posted by Drone

Totally unrelated but I want to post this amazing video made by JAPAN INSTITUTE OF SCIENCE AND TECHNOLOGY here because it's awesome



It's called Quantum levitation. It's awesome what magnetic field, electric current and Lorentz force can do! They use liquid nitrogen for cooling.

If only superconductivity wouldn't need that brutal cooling this technology could be used for real transportation! Maybe somewhen somewhere ...

Wow, that really was awesome. You could see the precise control they had over the cars too, round every bend and hump.

[Drone]

Can anyone rename my thread to Quantum Mechanics & Co. ? Because I want to post other news here without creating a new thread. Thanks.

Ok. By the grace of God Almighty and the pressures of the marketplace ... nevermind.

http://www.physorg.com/news/2012-01-...naked-eye.html

Quantum mechanics normally shows its influence only for tiny particles at ultralow temperatures, but a Cambridge team mixed electrons with light to synthesise supersized quantum particles the thickness of a human hair, that behave like superconductors.

They used some tricks:

Building microscopic cavities which tightly trap light into the vicinity of electrons within the chip, they produced new particles called polaritons which weigh very little, encouraging them to roam widely.

Polaritons are awesome because they entangle themselves quantum mechanically. Yes as always laser was involved

Injecting them in two laser spots, they found that the resulting quantum fluid spontaneously started oscillating backwards and forwards, in the process forming some of the most characteristic quantum pendulum states known to scientists, but thousands of times larger than normal. The resulting quantum liquid has some peculiar properties, including trying to repel itself. It can also only swirl around in fixed amounts, producing vortices laid out in regular lines.

Mind blowing.

By moving the laser beams apart, scientists directly controlled the sloshing of the quantum liquid, forming a pendulum beating a million times faster than a human heart.

Why did they do this? Because this is important for science and technology.

The goal of the work is to make such quantum states using an electrical battery and at room temperature, which would allow a new generation of ultrasensitive gyroscopes to measure gravity, magnetic field, and create quantum circuits.

[Drone]

Another interesting article which tells how physicists cool semiconductor by laser

Very interesting because cooling was achieved by warming LOL!

As always researchers combined two worlds – quantum physics and nano physics. Lasers, entanglement, electrons, near zero temperatures ... you'll find it all there.

http://www.physorg.com/news/2012-01-...tor-laser.html

They managed to produce a nanomembrane that is only 160 nm thick and with an area of more than 1 mm2!

In the experiment scientists shine the laser light onto the nanomembrane in a vacuum chamber. When the laser light hits the semiconductor membrane, some of the light is reflected and the light is reflected back again via a mirror in the experiment so that the light flies back and forth in this space and forms an optical resonator. Some of the light is absorbed by the membrane and releases free electrons. The electrons decay and thereby heat the membrane and this gives a thermal expansion. In this way the distance between the membrane and the mirror is constantly changed in the form of a fluctuation.

"Changing the distance between the membrane and the mirror leads to a complex and fascinating interplay between the movement of the membrane, the properties of the semiconductor and the optical resonances and you can control the system so as to cool the temperature of the membrane fluctuations. This is a new optomechanical mechanism, which is central to the new discovery. The paradox is that even though the membrane as a whole is getting a little bit warmer, the membrane is cooled at a certain oscillation and the cooling can be controlled with laser light. So it is cooling by warming! We managed to cool the membrane fluctuations to minus 269 degrees C", Koji Usami explains.

You ask why this is so cool? Because this discovery reconciles quantum mechanics with macroscopic materials to explore the Optomechanics (the interaction between light and a mechanical motion). The potential of optomechanics could pave the way for cooling components in quantum computers. So you no longer would need liquid helium, just lasers Laser cooling FTW!

And now pics:



Vacuum chamber



Koji Usami shows nanomembrane.



Laser controlled with a forest of mirrors hits the nanomembrane.

[Drone]

Now scientists want to observe 'Quantum Criticality' but they didn't get ultracold temperatures yet:

University of Chicago physicists have experimentally demonstrated for the first time that atoms chilled to temperatures near absolute zero may behave like seemingly unrelated natural systems of vastly different scales, offering potential insights into links between the atomic realm and deep questions of cosmology

Lasers and vacuum chamber is the best cooling system.

Scientists use sets of crossed laser beams to trap and cool up to 20,000 cesium atoms in a horizontal plane contained within an eight-inch cylindrical vacuum chamber. The process transforms the atoms from a hot gas to a superfluid, an exotic form of matter that exists only at temperatures hundreds of degrees below zero.

That's interesting and cool

The experimental apparatus includes a CCD camera sensitive enough to image the distribution of atoms in a state of quantum criticality. The CCD camera records the intensity of laser light as it enters that vacuum chamber containing thousands of specially configured ultracold atoms. "What we record on the camera is essentially a shadow cast by the atoms," Chin explained.

Not cold enough tho

The UChicago scientists first looked for signs of quantum criticality in experiments performed at ultracold temperatures from 30 to 12 nano-Kelvin, but failed to see convincing evidence. Last year they were able to push the temperatures down to 5.8. "It turns out that you need to go below 10 nano-Kelvin in order to see this phenomenon in our system" Chin said.

I wish them luck. Because this is one of the most important things.

http://www.physorg.com/news/2012-03-...ultracold.html

[slyfox2151]

can you Quantum Entangle 3 objects? or more?

[Damn_Smooth]

Originally Posted by slyfox2151

can you Quantum Entangle 3 objects? or more?

I can't.

[AphexDreamer]

I'm sorry but all I can think and hope for is for a Portal Gun.

Originally Posted by slyfox2151

can you Quantum Entangle 3 objects? or more?

Yes. http://en.wikipedia.org/wiki/Quantum_entanglement

[Drone]

A team that includes scientists from USC has built a quantum computer in a diamond, the first of its kind to include protection against "decoherence" – noise that prevents the computer from functioning properly.

Yeah decoherence is really annoying. But the good news is the quantum computing becomes more stable and reliable. They added some impurities to that diamond:

The team's diamond quantum computer system featured two qubits, made of subatomic particles. The spin of a rogue nitrogen nucleus became the first qubit. In a second flaw sat an electron, its spin became the second qubit. Electrons are smaller than nuclei and perform computations much more quickly, but also fall victim more quickly to "decoherence." A qubit based on a nucleus, which is large, is much more stable but slower.

As always we have a dilemma. Faster = less reliable, slower = more stable. They needed to babysit this process to protect it from nasty decoherence.

This solid-state computing system was the first to incorporate decoherence protection – using microwave pulses to continually switch the direction of the electron spin rotation. "It's a little like time travel," Lidar said, because switching the direction of rotation time-reverses the inconsistencies in motion as the qubits move back to their original position.

They tested this on Grover's algorithm (a problem when you need to search for a name in a phone book when you've only been given the phone number) and it kinda worked.

http://www.physorg.com/news/2012-04-...t-diamond.html


other info:

http://phys.org/news/2012-04-entangl...conductor.html
http://phys.org/news/2011-05-genuine...anglement.html

more:

http://phys.org/news/2012-04-evidenc...-fermions.html
http://phys.org/news/2011-10-exotic-...-approach.html
http://phys.org/news/2011-04-quantum...ts-limits.html

[Drone]

Teh qwantum interwebz is one step closer, weeeeee!

Physicists at the University of Vienna and the Austrian Academy of Sciences have achieved quantum teleportation over a record distance of 143 km. In a quantum teleportation experiment, quantum states are exchanged between two parties over long distances. The process works even if the location of the recipient is not known.

That's cool. Scientists have successfully transmitted quantum states between the two Canary Islands.

The photons had to be sent directly through the turbulent atmosphere between the two islands. The use of optical fibres is not suitable for teleportation experiments over such great distances, as signal loss would be too severe. To reach their goal, the scientists had to implement a method known as 'active feed-forward'.

It's a new kind of protocol for the transmission of information between quantum computers. Conventional data is sent alongside the quantum information, enabling the recipient to decipher the transferred signal with a higher efficiency. Their next goal is satellite-based quantum teleportation, which should enable quantum communication on a global scale. Well done, thumbs up!

http://phys.org/news/2012-09-km-phys...-distance.html

[Velvet Wafer]

all of that happening within not even a year... i guess there is something big coming in the next 10 years

[Drone]

A research team led by Australian engineers has created the first working qubit based on a single atom in silicon, opening the way to ultra-powerful quantum computers of the future. The team was able to both read and write information using the spin of an electron bound to a single phosphorus atom embedded in a silicon chip.

That's great. It means that technology can be built on silicon chips based on single atoms. They knew how to read the state of an electron's spin and now they can write the spin state.

The new result was achieved by using a microwave field to gain unprecedented control over an electron bound to a single phosphorous atom, which was implanted next to a specially-designed silicon transistor. UNSW PhD student Jarryd Pla, the lead author on the paper, says: "We have been able to isolate, measure and control an electron belonging to a single atom, all using a device that was made in a very similar way to everyday silicon computer chips."

Good news indeed. The team's next goal is to combine pairs of quantum bits to create a two-qubit logic gate – the basic processing unit of a quantum computer.

http://phys.org/news/2012-09-single-...k-quantum.html

[Drone]

The Vienna research team led by Anton Zeilinger has achieved a new milestone in the history of quantum physics: The scientists were able to generate and measure the entanglement of the largest quantum numbers to date.

Laser beam exhibiting a superposition of 100 right-handed and 100 left-handed quanta of orbital angular momenta, resulting in 200 bright spots on the inner ring.

The researchers developed a new method for entangling single photons which gyrate in opposite directions. This result is a first step towards entangling and twisting even macroscopic, spatially separated objects in two different directions.

Sounds exciting.

http://phys.org/news/2012-11-world-e...nt-quanta.html

[3870x2]

We are getting dangerously close to quantum computing. It is great to see something like this in my lifetime.

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