Three Electrons Entangled

An anonymous reader writes "Science Blog reports on Michigan researchers who have managed to entangle three electrons at once. "The quantum entanglement of three electrons, using an ultrafast optical pulse and a quantum well of a magnetic semiconductor material, has been demonstrated in a laboratory at the University of Michigan, marking another step toward the realization of a practical quantum computer. While several experiments in recent years have succeeded in entangling pairs of particles, few researchers have managed to correlate three or more particles in a predictable fashion.""

hmm..

[C21]

one step foward to achieving technology that can approach modeling the universe at 0 seconds old...

Re:hmm..

[eglamkowski]

What would be the point of a model a second 0? We're already pretty close to that. What we really need is a model of second -1! But unfortunately, no amount of quantum physics will ever tell us what existed before the bigbang.

Re:hmm..

[C21]

second 0 = point of singularity. I'm sure physicists across the world are wondering exactly what the rules of physics are for such a situation. You are wrong in saying we are close to knowing what second 0.00 is, we are VERY far from understanding even the basic rules that would govern such a situation.

Re:hmm..

[HorsePunchKid]

I guess we have have some sort of picture of what things were like at one plank time after "time zero". This is something like 10e-43 seconds. Which sounds extremely close to zero. Almost unimaginable close. But then I think, as long as you don't actually go back to the singularity, time is continuous, so there's just as much to be discovered between 10e-86 and 10e-43 seconds as there is between 10e-43 and 1 second (and between that and 10e+43, for that matter). But then I think that it's very naive to assume that time is continuous in the same sense that the real numbers are continuous. In fact, it seems like some theories [livingreviews.org] actually imply that space and time are discrete. Check out Smolin's book, Three Roads to Quantum Gravity [amazon.com] for a nice introduction to the topic.

Ashcrorgy

[orangesquid]

Wow! A real orgy! Now which States, exactly, is this legal in?

I'm all for electron entanglement, as long as Ashcroft doesn't decide it's drug paraphernalia. I mean, after all, if one of those electrons was ever part of 9,1-tetrahydracannabinol (did I get that right?)...

Re:Ashcrorgy

[iggymanz]

3 way entanglement is also a problem if any of the electrons is less than 18 years old or more than two years younger than any of the others in the case of more than one being less than 18 years old

Re:Ashcrorgy

[diggitzz]

Well, if they were all born at the same time, that makes them identical twins so it's completely illegal for them to entangle in the first place.

You can still entangle with them, one at a time, in most states, as long as they're over 18, but since they're probably moving relativistically you'll be waiting quite some time. ;)

Algorithms?

[astroboscope]

Can anyone outline some algorithms that use 3 way entanglement?

Re:Algorithms?

[diggitzz]

A 3-D Shor's Algorithm, perhaps?

The true Qsort

[onallama]

permute_array(array);
if (is_sorted(array))
return array;
else
destroy_universe();

Qubits

[Ichijo]

I remember a Bill Cosby skit about this subject. It went something like this:

God: "I want you to build a quark."
Noah: "Right... what's a quark?"
God: " Make it 300 qubits by 80 qubits by 40 qubits."
Noah: "Right... what's a qubit?"

Okay, how about this one?

[Izanagi]

Three electrons walk into a bar...

One electron says to the bartender ...

[diggitzz]

"I'm feeling a bit down today."

The other two respond, "Wow, that really puts a whole new spin on things."

not particularly on topic, but...

[gid13]

my favourite physics geek joke was always "yo mama's so fat a neutrino wouldn't pass through her" :)

Re:One electron says to the bartender ...

[wowbagger]

How can an electron be down? Quarks can be down, but leptons cannot be.

Re:One electron says to the bartender ...

[diggitzz]

Sure they can. Electrons have a 1/2hbar spin, which can be oriented in any direction, depending on how you set its basis.

Re:One electron says to the bartender ...

[diggitzz]

Forgot to add:

There is a quark named "down", but it doesn't necessarily have a spin oriented downward. Like an electron, it has a 1/2hbar spin which can be oriented in any direction to conserve angular momentum.

Here is a click-through standard model chart [particleadventure.org], and Here is an easy description of electron spin [gsu.edu].

Re:One electron says to the bartender ...

[wowbagger]

What I meant was that only quarks can "be" down, as in the down quark.

An electron may have a down spin, but only a quark can "be" down.

Re:One electron says to the bartender ...

[diggitzz]

Well the electron only said he was "feeling a bit down" ...=P

I find it humorous that you're willing to tear apart my already-lame joke on something like whether the electron was "feeling" down or claiming to actually "be" down (which he wasn't), whilst completely ignoring the fact that these electrons are feeling and talking to a bartender in the first place, the more obvious impossibilities. ;)

Re:One electron says to the bartender ...

[wowbagger]

And I find it humorous that you are responding to my humorous attempt to extend your humor as though it were an attack on your manhood.

You made a joke, I made a joke. You misunderstood my joke, I explained it.

Re:One electron says to the bartender ...

[dmiracle]

huh? Does the name down mean the quark is down? I mean we talk about spin up and spin down and somehow there is an idea of a projection operator giving you a negative number. In QM the idea of down isn't really the same as the idea of down in say, my appartment. Here I have a down determined by gavity. It means something completely different. So when it comes to naming quarks, is the idea of down more fundamental just because the particle is more fundamental? My conjecture is no. Many particle names say very little about the actual particle. Hell even calling them particles is somewhat arbitrary.

Not to be a downer but there isn't some physical observable called "downness". Of course if you hit the books and start doing some serious predictions you may get to name an observable; and if you do you sure as hell can call it the downness of particles.

Quantum Teleportation?

[bill_mcgonigle]

So does this mean you can now do Quantum Teleportation [ibm.com] without destroying the original? Well, the original could be momentarily destroyed, but if you have a second entangled particle you can rebuild it almost instantly, so it's like it's never destroyed. For all I know it wouldn't surprise me if you could destroy the particle after it's been recreated, seeing how quantum physics exists primarily to remind me how dumb I really am.

Re:Quantum Teleportation?

[wowbagger]

The first particle isn't destroyed in quantum teleportation. What is destroyed is the quantum state of they particle - what spin/polarization it had.

To put it very loosely - in quantum teleportation, the original object would be scrambled. But it would still exist as mass.

Re:Quantum Teleportation?

[exp(pi*sqrt(163))]

No. The No Clone Theorem sees to that. Basically QM is linear but cloning a particle state is non-linear. Being able to keep the original state means that the state has been cloned.

Q-Crypto

[Ratso Baggins]

Does this mean (theoretically) you could entangle a third photon to an already entangled pair and then strip it off - of course without harming the originally entangeled pair?

Re:Q-Crypto

[QEDog]

No. Since the three of them are entangled, they all collapse together when one is measured. The important thing about this article is that you need many entangled electrons to make most complicated calculations, the same way you want many logic gates connected to each other in a computer.

WOW

[_ph1ux_]

Why do I hear this guy yelling [leskobooks.com] this article to me when I read it?

Re:Once more

[You're All Wrong]

You're funny.[*]

I'm in the fucking field.

Look at what Shor himself has said about Quantum Factoring, butt-wipe. If I think it'll never work, and Shor thinks it will never work, and Shor invented the fucking algorithm then personally I think it's a pretty good bet that I'm in the right, and you're wrong.

(google groups on sci.physics for refs)

YAW.

[* funny is a sad pathetic ignorant kind of way]

Re:Once more

[You're All Wrong]

Wrong again - I am interacting, but you're just an anonymous shitwipe.

YAW.

Unfortunately...

[Hard_Code]

...it got "weird", and now the three electrons are not talking to each other.

So would this mean ...

[GreatOgre]

more focus on ternary (I think that's right) computing?

Re:So would this mean ...

[Dr. Evil]

Naw, quantum computing is damned odd. It really has nothing to do with conventional computing.

Maybe a quantum coprocessor or API (calling on a network resource) for stuff like cracking encyryption keys or well... has anybody come up with a legitimate application yet?

Mom! My electrons are entangled again!

[azav]

Aw man! Now who are we gonna get to pull em apart now that they're all tangled up.

Quantum RAID

[dbullock]

Redundant array of inexpensive electrons

Actually...

[keller]

Wouldn't this be a RAIE?

Don't get too excited

[exp(pi*sqrt(163))]

What they have done is carry out a particular entangling. Getting a bunch of particles entangled is otherwise a commonplace occurence. Any bunch of particles that interact non-trivially is entangled. It's the non-entangled states that are the exception!

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