High Temperature Bose-Einstein Condensation Observed

ultracool writes "Two separate research groups claim to have observed Bose-Einstein condensation (BEC) in quasiparticles at much higher temperatures than atomic BEC — one at 19 Kelvin and the other at room temperature. The 19 K BEC was composed of half-matter, half-light quasi-particles called polaritons, and the room temperature condensate was composed of 'magnons' (packets of magnetic energy). There is some skepticism among physicists as to whether these really are BECs. If they are true BECs, these experiments are the first evidence of them in the solid state." Just in case you need a brush up on BEC, like I did, check out the Wikipedia article on Bose-Einstein condensation.

Comments

Re:The Wiki article

[Zugok]

You could have tried the external links at the end of the page.

Can't Be

[Jah-Wren Ryel]

A high-temperature Bose-Einstein condensate? It can't be.
You know how the saying goes - "No highs, no lows, gotta be Bose!"

Oh wait, that's a different kind of Bose.

Nevermind.

Re:Can't Be

[Anonymous Coward]

Damn. No sense of humor.

Re:Can't Be

[hachete]

It was Bose-Eisenstein, all the way down the steps.

Re:Can't Be

[gstoddart]

A high-temperature Bose-Einstein condensate? It can't be.
You know how the saying goes - "No highs, no lows, gotta be Bose!"

Oh wait, that's a different kind of Bose.

As much as I'm gonna get marked off-topic for this ... to those of us who don't have 'golden ears', Bose speakers sound just fine. I rather like my set of four 201's which makes the basis for my AV system.

They never claimed to sell the speakers with the greatest degree of fidelity, they claim to sell speakers that sound good to the majority of listeners. Of course, that is true of most speakers sold in the world.

That 1% of people who *can* actually hear the difference aren't big enough to sway most speaker manufacturers. For the rest of us, most speakers are probably reasonably interchangeable anyway.

Cheers

Re:Can't Be

[Anonymous Coward]

... he's not talking about the bose speakers ... he's talking about BEC ... the bose speakers have nothing to do with this

Re:Can't Be

[gstoddart]

... he's not talking about the bose speakers ... he's talking about BEC ... the bose speakers have nothing to do with this

Actually, when he said "No highs, no lows, must be Bose" he was specifically talking about Bose speakers and making a joke. (Bose speakers shift things to the mid-range.)

Maybe you missed the part where he said "Oh, different Bose".

I know that Bose speakers has nothing to do with BEC, but the OP injected a funny, which did refer to Bose speakers. Which is what I responded to.

Cheers

Re:Can't Be

[Anonymous Coward]

They never claimed to sell the speakers with the greatest degree of fidelity, they claim to sell speakers that sound good to the majority of listeners. Of course, that is true of most speakers sold in the world.

Indeed, most speakers do sound good to the majority of listeners. But there is a lot more to it than just "sounding good." Ultimately, what it comes down to is bang for the buck. Bose, like Monster cable, charges premium prices for pedestrian quality.

That 1% of people who *can* actually hear the difference aren't big enough to sway most speaker manufacturers. For the rest of us, most speakers are probably reasonably interchangeable anyway.

Way more than 1% can hear the difference. The trick is to do an A/B comparison. Few people have the time or the energy to set up two speaker systems in the same room with approximately the same placement so that they can flip back and forth on the same material.

Many a/v stores do have the facilities to do provide a/b comparisons, but the rumours are strong, and the evidence even stronger, that part of the contract that all official Bose dealers must sign is that they are forbidden from setting up any A/B comparisons with Bose speakers, at least no comparisons where Bose has not specified the parameters, including the competing speakers.

Without the ability to do an objective test, you are right, probably less than 5% of the population can tell the difference.

Re:The Wiki article

[NinjaFarmer]

I did check the Wikipedia article, and it just said something about how Einstien was still alive and that the effects of Bose-Einstien condensation had tripled over the last year...

Are you sure you are reading from the correct encyclopedia? You should probably check the article on uncyclopedia to be sure....

Re:The Wiki article

[Anonymous Coward]

That's strange, because when it comes to only pretending to read something I stare at for a few minutes, I can hold my own against the best of them, and I didn't notice anything of the sort. Then I checked the history page, and unless you're writing this comment from Wednesday (you're not), nobody's changed anything...
Anyway, thanks for having me, dinner was marvelous, we should do this again sometime...
hugs & kisses & hearts & flowers,
~ken

Solid State?

[FlavorText]

I thought Bose-Einstein condensate was a completely different state of matter. How then, could it appear in a "solid state"?

Re:Solid State?

[k98sven]

I thought Bose-Einstein condensate was a completely different state of matter. How then, could it appear in a "solid state"?

Good question. And damn hard to explain in terms that don't sound insane to the layman :)

Thing is, the condensed particles here aren't the particles that make up the solid. They're not quite real particles, even. They're so-called quasiparticles, which are a fancy way condensed-matter physicists have of describing what the rest of us call "interactions". Each interaction has its own kind of quasiparticle, (and some silly name ending with -on) and they're basically described just like real particles are. The trick is you can describe the system in terms of these virtual particles instead of the real ones and simplify the problem.

To give an analogy, you could think about a bubble moving through some liquid. The bubble isn't actually a real particle - it's just the overall effect of a bunch of gas molecules pressing and bouncing against the liquid molecules. But thinking of it as just a "bubble particle" is a lot simpler.

Anyway. So the condensate here isn't made up of the solid's atoms. It's made up of quasiparticles. And this is why there's some debate on whether this should be called a BEC or not. On one hand, they can, and do have coherence here. On the other hand, they're just not really real! :)

But it's also pointed out they're extremely short-lived. It's indeed questionable if you can call something a BEC if it's short-lived, because a BEC is supposedly a low and stable state. (So the question becomes "How stable should it be to be a BEC?") But regardless of that, it's no less interesting.

My guess is, people will probably continue to call every BEC-like kind of condensate a BEC. When the need arises to distinguish the two, they'll have to invent a new term for that context, like "quasiparticle condensate" or something.

Re:Solid State?

[raka]

The bit about "solid state" was almost B.S.

Normal matter, including every BEC I have heard
of is made of atoms, which are quantum particles.
However solids, like every other kind of matter
(even BECs!) support excitations, which can
also be quantum particles (or quasi-particles).

It seems that they have made a BEC out
of the quasi particles in in a solid (which
is not itself a BEC).

Re:Solid State?

[wass]

Let me attempt a hopefully-understandable explanation. I'm a graduate student in experimental condensed-matter physics.

You can think about it in a coneptually-easier way by thinking about vibrations, which is more intuitive. The simplest model in which to think about vibrations would be in one dimension. Imagine you have a collection of some equal masses, equally spaced, with equal springs between each of those masses. If you excite the system anwhere (ie, push some of the masses), it will vibrate throughout the whole system because each 'atom' is coupled through the springs. The individual excitations of such a system would be the collective 'modes' of oscillation of the system. A mode is a specific oscillation that once set up will continue uninterrupted (without friction). For a simple one-dimensional system like the modes would be a sinusoidal oscillations of the system, where the wavelength of each mode would be the twice the length of the 'crystal' divided by an integer. See the wiki page on the Normal Mode with a cute animation.

You can extend this to three-dimensions by considering a three-dimensional grid of massive atoms, connected by springs. Real crystals don't have to be cubic, they can have a number of various arrangements (hexagonal, trigonal, diamond structure), and the effective spring constants can be different in different directions. But N masses, in 3 dimensions, will have 3N distinct modes. What's important to see is that each mode would have its own frequency, and wavelength, and typically the speed of propagation of each mode doesn't have to be the same. Also of note is that each mode has its own energy.

If you now consider a real crystal, and apply these same concepts but within the realm of quantum mechanics, you get a similar result, but each 'mode' now becomes a 'quanta' of lattice vibration. These vibration quanta are called phonons, which are bosons (they have spin 0, and bosons have integer spin). Even a small chunk of crystal will have on the order 10E23 atoms, so this is a huge number of allowed quantizations, and they can be thought of as a continuum. Each allowed 'mode' will again have its own frequency, wavelength, and energy. If you have a chunk of crystal at any non-zero temperature, any of the modes above the ground state (the ground state is the mode with the lowest allowed energy) can be 'occupied' with a finite probability. As you approach zero temperature, the probability of any mode above the ground state being occupied approaches zero.

A Bose-Einstein Condensate refers to an effective phase transition that happens as you cool the system and it becomes harder to excite the higher energy states as system becomes highly occupied in the ground state. There is a phase transition, the presence of which can be manifested by different qualities in things like specific heat, magnetization, magnetic susceptibility, etc. The crystal is still a solid crystal per-se (meaning it has a well-defined atomic ordering) but the occupations of the various modes of the system will drastically change, building into a near divergence at the ground state.

In the 'magnon' case as mentioned in TFA, you can think of it like phonons described above, but instead of two atoms exchanging vibrational energy, they are exchanging magnetic energy. Each electron is a spin-1/2 dipole (a fermion, not a boson), and there are interactions between two neighboring spins. Spin interactions are highly model dependent, meaning the types of atoms and shape of the crystal has huge impact on the interactions, which is why some materials are magnetic and some are non-magnetic. If you quantize the magnetic interactions you get spin-waves or magnons, similar to the sine-wave vibrational modes of the lattice above except the direction of the spin-moment changes instead of the atom displacement in the lattice.

Re:Solid State?

[Anonymous Coward]

It's good to see that I'm not the only super-genius here.

Re:Solid State?

[Anonymous Coward]

No offense, but that explanation is almost entirely incomprehensible. It introduces unfamiliar terms ("crystal," "effective spring constants," "effective phase transition," etc.) with no context from which to infer their meaning, and uses words in ambiguous ways (for example, it took me a while to understand that a "mode" describes not a single back-and-forth motion, but rather a specific frequency of motion). Additionally, it provides no assistance in making significant conceptual leaps, such as the one from "modes" to this new and apparently redundant concept called "quanta."

I was lost long before you ever mentioned the Bose-Einstein Condensate. It's possible you were cursed with a particularly slow pupil, I'll admit. But even so, your lesson plan was no help either.

I understand you're trying to help, at least, and I'm sure everyone appreciates the effort. But God, man, please try to work on your teaching skills before you're asked to actually start teaching.

Re:Solid State?

[Scarblac]

I parse that as "we're making shit up, then condense that into something real, at room temperature." :-)

Seriously, I had no idea Slashdot articles could be this far above my head.

Re:Solid State?

[doug363]

On the question of whether a BEC made of quasiparticles is really a BEC: a laser beam fits (some) definitions of a BEC of photons, but most physicists don't immediately think laser beams when someone talks about BECs. I'd think that these "BECs" would be considered in the same way: technially a BEC perhaps, but not the definitive example of one. After all, the quasiparticles are just quantized vibrational modes of non-EM fields.

Re:Solid State?

[Gulthek]

Awesome comment, thanks!

Although for future lecturing reference, you kinda lost me when we moved onto real crystals. But that may just have been the innate complexity of the subject matter.

Re:Solid State?

[cybrpnk2]

Perhaps you can answer (or speculate about) a question I've always wondered about concerning BECs. Say you create a BEC from radioactive atoms and you keep it cooled down for several half-lives of whatever element isotope you've used. What happens? Does being in a BEC halt radioactive decay? Does radioactive decay affect a BEC during its existence? Will the decay products pop out when the BEC warms?

Re:Solid State?

[kickdown]

I'm scared.

Re:Solid State?

[Anonymous Coward]

His explanation was completely comprehensible. And if he is ever asked to teach on this subject matter he will be teaching students who actually have a background in physics since this isnt something you see in your introductory physics courses. So with that in mind his teaching skills are on point.

Re:Solid State?

[Engine]

Being in a BEC does not halt radioactive decay. I don't see why it should.

Radioactive decay does affect a BEC. Firstly, it frees energy that will heat the BEC. A BEC of atoms is so cold that even recoils from (ordinary light) photons destroys it, then imaging what the recoils from the decay would do. Secondly, a BEC can only consist of identical particles. Emitting a alpha or beta particle leaves you with an other species and this can no longer be part of the BEC.

I am a Ph.D. student actually working with BECs so I should know what I am talking about. I am not as confident expressing my thoughts in english, so sorry for any confusion I might cause.

Re:Solid State?

[wass]

Sorry that I'm unable to boil all of quantum mechanics and solid-state physics into a single easily-comprehensible slashdot posting, while spending a maximum of 15 minutes writing it. I included a few mentions to wikipedia (eg on modes) to aid you, and also quoted certain terms for you to look up on your own. Any quoted terms below, please look up yourself if you don't understand. This post can hopefully get you started. But I can't believe I'm being criticized for spending my own time trying to help someone entirely unfamiliar with the field understand something.

A mode is the collective motion of the atoms in the crystal, not a single frequency. A mode will oscillate at a specific frequency, however. If you write the 'equations of motion' for all atoms in the crystal in 'matrix' form, the modes would correspond to the 'eigenvalues' of that matrix. I'm sure these sentence will confuse you, but again, I can't boil linear algebra anad its application to mechanics down into a few understandable sentences to be comprehended in only a few minutes. f I tried to go too basic into all the details that post would evolveee into a textbook sized tome.

So a crystal will have several different modes. This is very much like quantum mechanics, where energy states are quantized, and each so-called 'eigenstate' has a specific 'wavefunction' associated with it. These oscillatory modes are called 'phonons', which are 'bosons'. The 'magnons' referred to in the articles are different modes. In those cases it's not vibrations they're 'quantizing' but magnetic interactions. The electrons on the atoms in the lattice are tiny 'magnetic dipoles', which can rotate, interact with magnetic fields, interact with other nearby electrons, etc. Again, if this paragraph confuses you then look up the terms in quotes.

Re:Solid State?

[SimplyI]

Thanks for your post. It was articulate and informative. I had only ever known wikipedia's less in-depth explanation. It's unfortuneate assholes exist, yes. I guess since you offered a bit of an explanation he decided it was your duty to teach him everything you know. Oh well.

Re:Solid State?

[Anonymous Coward]

Being in a BEC does not halt radioactive decay.

Has anybody done such an experiment? Just for the hell of it?

How identical is 'identical'? All the particles have to be exactly the same charge, same isotope, etc?

What kind of particles have been used to create BECs so far? Some metal ions and now quasiparticles, of course, but has anyone made a BEC with (multiatom) molecules?

Thanks for satisfying my curiosity.

Re:Solid State?

[Yusaku Godai]

I think that rather than blaming the teacher you should blame your own lack of comprehension skills. My personal background in Physics doesn't extend much past that of a sophomore Physics undergrad, though I do have a strong background in math, and I thought that his post was entirely understandable and very eye-opening for me as to how all this stuff works, and what the research in TFA was trying to do.

Re:Solid State?

[Engine]

Not what I know of. Rb87, the most popular isotope used in these experiments is slightly radioactive, but the halflife is too long to make any difference.

Identical means the same isotope and same charge. Also only neutral atoms since any charge would make it very hard to achieve the density needed to achieve BEC (ions repel each other, you know). I don't think there is any BEC with ions.

Mostly alkali atoms have been used (the ones leftmost in the periodic table). These are the ones most straightforward to cool with lasers. They have also made BEC with spin polarized He. And yes, BECs with moleculs have been made. But I think the detection of these BECs are indirect. Usually, a BEC with atoms are made and then through manipulating the scattering length (the interaction between the atoms) with a magnetic field (Feschbach resonances) a molecular BEC is made.

If this answer is incomprehensible, it might be because it is Saturday night here and we are having a great party. I am a little (just a little) drunk right know ;-). (WTF am I doing on slashdot.)

Re:Solid State?

[Anonymous Coward]

Actually, I was trying to help him by pointing out specific ways in which his explanation lacked clarity, at least to a person with no background in physics or math, but a definite interest in understanding the article. My hope was to let him know exactly which aspects of his lesson plans need work. Sorry if that makes me an "asshole."

Re:Solid State?

[shadwstalkr]

You talk purdier than a two dollar whore.

Seriously though, your explanation is a lot easier to understand than Kittel's.

Re:Solid State?

[Starker_Kull]

Sorry that I'm unable to boil all of quantum mechanics and solid-state physics into a single easily-comprehensible slashdot posting

Unacceptable! I'm sure the AC who was complaining about unfamiliar words like "crystal" could write a similar length article on some easy technical topic, like how to write a C compiler, without using technical terms like 'bit' or 'keyboard' that might confuse...

Seriously, thanks for the explanation - some of us appreciate it when a professional in a field takes the time to give an accurate description.

Re:Solid State?

[Anonymous Coward]

oh yeah? well, you're just a big poopie-head!

Re:Solid State?

[on the 8ball]

no, you're not an "asshole", you're an analogy to the particles called "bosons", you're a "bozo". His post was great, your reply was asinine.

Just think about *this*

[bcat24]

In the time it took you to read that Wikipedia article, David Banh wrote and published a groundbreaking paper on the subject.

Re:The Wiki article

[bcat24]

Yeah, because nobody can edit external links on Wikipedia articles.

Solid state?

[RyanFenton]

How can a mishmash of atoms collapsed into the same space (b-e condensate) have a 'solid state'? Their radius' overlap. Is this more like a gas freezing without any other transition?

Ryan Fenton

A *live* Wikipedia page? Thanks guys. Nice work.

[NereusRen]

Oh, for the love of...

Editors, if you link a Wikipedia page from the summary, PLEASE link a historical revision. That way, whatever vandalism happens won't affect the link, and thus fewer people will be tempted to even vandalize at all.

Seriously, do the editors have any sense at all? It's not like this is a new problem.

Bose

[Anonymous Coward]

I don't know how this can make the front page. Bose is overpriced junk. Thanks for the Slashvertisement!

So Star Trek was right...

[Anonymous Coward]

But can you reverse the angular momentum of polaritrons in order to counteract a magneton beam?

Re:So Star Trek was right...

[Anonymous Coward]

It depends if the magneton beam is in sinusoidal form, and has been generated from a dilithium pool.

Ok, I'll be waiting outside.

Re:So Star Trek was right...

[AJWM]

Yes, but only if you route the plasma conduits through the Heisenberg compensators.

Re:So Star Trek was right...

[MobileTatsu-NJG]

"But can you reverse the angular momentum of polaritrons in order to counteract a magneton beam?"

It's like filling a ballon until it pops!

Hey baby... like my shiny Commander's pips?

Can anyone read the articles.

[raka]

Unfortunately I'm at home, so I can't read the actual articles.
The main thing I am wondering about is dimensionality. I've seen
lectures before where people have come up with pancake like-systems
that are *like* BECs at 1 Kelvin, but unfortunately you can't meet the
pedantic requirements for BEC in less than 3d.

But if these systems are 3d, then it seems reasonable. We are talking
about quasi-particles here. As one of these abstracts says, their
(effective) mass is much less than that of an atom, therefore for they
can have much higher energies than atoms of similar momentum. Because
BEC is all about getting (the uncertainty of) momentum * (uncertainty of)
position down below a magic number, it seems reasonable.

Re:Can anyone read the articles.

[k98sven]

Kasprzak et al. is 2d, Demokritov et al is 3d.

I haven't delved into the details, but the latter one seems to have a much higher lifetime as well, and I guess is the more proper BEC of the two. I presume it's the more interesting result, since as you say (and the references indicate) the 2d-quasiparticle-condensate thing has been done before.

(Since it's not my field, don't put too much faith in my impressions of what seesm to be 'interesting'. For all I know, this could be undergrad-level condensed-matter physics by now ;) )

Re:Can anyone read the articles.

[Yehooti]

Certainly the math escapes me after so many years but I think that the chronos sinclastic infindubula theorms cover this nicely. Clark covered this nicely in the early '70's.

Re:Can anyone read the articles.

[raka]

You are probably right, but ... Deveaud-Plédran happily dismisses both assertions. "BEC is forbidden only in two dimensions for an infinite system without disorder. We have a finite system with disorder, so standard BEC is allowed. And despite the quasiparticle nature and very short lifetime, we have shown that we are able to get a thermal equilibrium."

Well the bit about disorder is prossibly a triumph of hope over experience, but they are right about the finite system size. They say 2-d systems can't have phase coherence over infinite distances, but who cares as long as the coherence is as big as the device! Still, in practice people probably will care about picosecond lifetimes, with or without thermal equilibrium.

Re:Can anyone read the articles.

[God Of Atheism]

It is indeed, at least I did learn about it in an undergraduate course on statistical physics.

However, one of the authors of the first claimed that what they created was a proper BEC as well since it was finite. He claimed it was only impossible to have infinite two dimensional BECs. I don't have any idea as to the validity of this claim though.

Re:A *live* Wikipedia page? Thanks guys. Nice work

[Pink Tinkletini]

And whatever corrections are made won't be updated in the link, either. With many eyes, after all, all errors are shallow--isn't that the founding principle of Wikipedia? A crush of visitors should improve the article beyond anything seen in Britannica or the New York Post.

Wait, what?

Re:The Wiki article

[LurkerXXX]

Even better, the idiots who insist on using as a reference a website any 12-year-old can change whenever he feels like it could at least learn to use it right.

Dear Wikipedia fanboys,
Learn to fucking reference it right. When you make a link to it, include the full link to the timestamp of the state it is in when you read it.

Example: http://en.wikipedia.org/w/index.php?title=Bose%E2% 80%93Einstein_condensate&diff=78635928&oldid=78633 658
would have been the correct way to reference Wikipwdia for the grandparent wiki fanboy.

That way, while the content may or may not be either excellent material written by an expert on the field, or the ramplings of a moronic 12-year-old who felt like he knew how things 'work' better than the Ph.D. in the field whose entry he just erased, at least you know the reader will be looking at the same content you did.

huh

[sydres]

I always assumed probably wrongly that a B-E condensate was when groups of atoms dropped to an energy state that allowed them to act like one very large and coordinated atom. Would not thermodynamics keep in a system like a B-E this organization from occurring at temps that much higher than zero kelvin, forces like vanderwahls and electro weak forces. or if some physisististist care to enlighten a mathematical wannabee

Re:huh

[raka]

You intuation is right.

They cool thing about BEC is that it violates that intuition. Until B&E published, everyone thought that "much higher than zero kelvin" meant when that (in the appropriate units) the temperature (i.e. roughly the average energy per particle) had to be (much) less than the difference in energy between lowest state and any of the the others. If you think about this assumption, you will see that it nearly comes from
Bolzman's law (and if you don't know what Boltzman's law is, and are not a science or engineering student, you probably don't care).

Satyendranath (sp?) Bose came up with the bombshell that although Bolztman's law is right Bolztman's law operates differently for quantum particles. Some quantum particles (nowadays called Bosons) are more likely than expected to get into the same quantum state. They will do this wheneve the temperature is low enough
that their momentum uncertainty forces their position uncertainty to be at least as large as the typical distance between partciles (i.e their wavefunctions must "overlap" coherently, and again if you don't understand, you don't care).

So even ordinary BECs happen at relatively high temeratures. Unfortunately these temperatures are still in the nanokelvin range, at least for atoms under experimental conditions.

Re:huh

[sydres]

so its almost like when electrons become stimulated in a laser they all jump to pretty much identical states and act like a coherent population, or at least till one drops back causing all to follow suit, only in a B-E its that they give up energy to act as a "population" and its not just electrons doing this. At least that is how I am envisioning it, thanks for enlightening

Wow

[SpacePunk]

"Magnons are the quanta of magnetic excitations in a magnetically ordered ensemble of magnetic moments."

This statement caused my bogometer to break. Now the needle is stuck all the way right at WTF.

Re:Wow

[samurphy21]

This feels like an episode of Stargate SG-1 where Carter says something technical to explain a wormhole phenomenon, and all the military guys start looking at each other like monkeys looking for poop to fling while I'm yelling at the screen in frustration because whatever she said, while sci-fi-ish in its veracity wasn't as hard to follow as the writers tried to make it seem.

Look at that, that's all one sentence, isn't it?

Re:Wow

[raka]

Nahh, all the magenets are there for their reasons. Even if one of the reasons was that someone was not thinking about writing sensible Enslsigh.

Re:Wow

[MustardMan]

Ok, since your "bogometer" seems to go off at one of the most highly respected scientific publications, on the planet... let me do a little physics-to-layman translation for ya.

quanta: packets of things that are quantized, like, you know, everything that happens at the atomic scale
magnetic excitations: increase in magnetic energy, for example by periodically flipping the moment like an oscillator
magnetically ordered: lined up
ensemble: group of stuff
magnetic moments: little tiny magnets formed by the electron spin.

A photon is a quanta of light energy, an energy level in a hydrogen atom is a quantized electron orbit, and a magnon is a quanta of magnetic energy. It's described using perfectly normal terminology that most undergrad physics students should be comfortable with.

Re:Wow

[SpacePunk]

------------------
Ok, since your "bogometer" seems to go off at one of the most highly respected scientific publications, on the planet... let me do a little physics-to-layman translation for ya.
-------------------

yeah, yeah, yeah. I get it... it's a nerd jerk off magazine. It all becomes more and more trekish every year.

Re:The Wiki article

[Pink Tinkletini]

On September 29th, this article was linked from Slashdot, a high-traffic Internet site.
All prior and subsequent edits are noted in the revision history.

I just love what that template leaves unexplained.

What 'chu talking about WIllis?

[OverlordQ]

If they are true BECs, these experiments are the first evidence of them in the solid state.

Bah real physicists start the day with a nice large glass of Bose-Einstein Condensate (Now with Calcium)

More like O'Neil.

[raka]

Carter: "Well how do *you* think it's done".

Oneil: "Magnets."

Re:More like O'Neil.

[KDR_11k]

Who knows what makes these inanimate objects dance their infernal jitterbug?

I do! I do! I think they're controlled by a series of really big magnets buried under the Earth's crust.

You're an ignorant dolt, Max.

High Temp Booze Condensation?

[s-orbital]

I was noticing it was pretty hot this afternoon. I guess Einsteins beer was left in the sun too long, and even though it was warm, condensation still formed on its bottle.
A pretty amazing scientific phenomenon alright!

Re:High Temp Booze Condensation?

[KDR_11k]

Is that the beer he used the chisel on?

Yes, I really am dumb.

[raka]

By the way "magenets" and "Enslisigh" were not put there on purpose, out of any sense of irony. They are there because I can't write sensible English. I might give Enslisigh a try though....

Re:A *live* Wikipedia page? Thanks guys. Nice work

[Jeff DeMaagd]

"We gave the word mob a bad name!"

Re:The Wiki article

[Rei]

*Whoosh*

The Number of Elephants Has Tripled!.

What?

[ms1234]

Someone understood that?

The thing I love about science...

[Arivia]

it's the only way to lose an English major in an English sentence.

Re:The thing I love about science...

[TheLink]

In Law, there's more than one way to lose an English Major in an English sentence. ;)

BEC = world peace

[Anonymous Coward]

A BEC at room temperature would provide for macroscopic quantum phenomenon.

BECs are the fifth state of matter. If you could induce an object to exist in a state like a BEC, you'd experience some rather magical possibilities.

When the DeBroglie wavelength exceeds the molecular mean spacing, the atoms become a BEC. This is when all the quantum wave functions of the atoms exist in the same stage, so a million atoms equals the same as one. This is only possible with bosons, so their electrons can exist in the same energy states (integer spin values, unlike fermions).

So basically, if the atoms exist in the same quantum wave function the conductivity increases a trillion-fold, the BEC will start to crawl up the sides of containers exihibiting anti-gravity, and the entire thing will weigh as much as one individual atom.

Therefore, it's hypothesized that if regular objects could exist as BEC, you could drop that object through a table (exhibiting aspects of quantum tunneling), you could make glass superconduct, and thus supersede the laws of thermodynamics, revolutionzing the world with unlimited energy, ridding our dependence on fragmented energies, and otherwise institute world peace.

Of course, it's impossible.

Re:The Wiki article

[Broken scope]

The site make it very easy to pick a version of a page to link. The left side of the page say cite this article. Click it and use the link it provides.

Re:The Wiki article

[Anonymous Coward]

... idiots ... any 12-year-old can ... fanboys ... learn to fucking reference ... ... ramplings of a moronic 12-year-old ...

Dude... I am so feeling the love.

It's times like this I just know teh intarweb is the most beautiful thing, evar.

I see.

[Anonymous Coward]

This bodes poorly for the release of the playstation 3, then.

Re:The Wiki article

[Anonymous Coward]

Wikipedia fanboys

Perhaps we could call them "wikipediaphiles".

Cold Fusion, Hot BEC

[Anonymous Coward]

Why do I get the feeling that a warm BEC is right up there with Cold Fusion?

Re:The Wiki article

[Tjeerd]

For people who still don't understand anything of it, there is a very good article here about Bose-Einstein. Even some nice applets to play with sliders to see how it all works.

Please translate.

[posterlogo]

I have a Ph.D. in biology, and I am interested in current research in many other fields as well. That said, I have no idea WTF the *significance* of the current breakthrough is. What does it mean? Why isn't there even a one sentence half-assed attempt in the summary? Thanks for the wiki-link. If I wanted to seriously brush up while trying to navigate the ridiculous wiki, I'd go there. Seriously, most people might just want to know why they should give a shit that BE condensation has been observed at solid-state. Don't get me wrong, I think there is something fascinating in all this, just wish the summary would have pointed to that aspect instead of regurgitating the so-called claimes of a breakthrough.

Re:Please translate.

[ultracool]

How about you RTFA? "What practical applications will this lead to? "We are still exploring the basic physics of this phenomenon," says Deveaud. "But just achieving this phase in the solid state is exciting. In the mid 1900s, transistors replaced vacuum lamps, and now most useful devices are made in the solid state," he explains. "Polaritons, although made with a photon, are really quasi-particles in the solid. It is likely that they can be manipulated much as electrons are -- an advance that has led to incredible new technologies such as the CCD chips in digital cameras."

Re:Please translate.

[raka]

Seriously, most people might just want to know why they should give a shit that BE condensation has been observed at solid-state. Don't get me wrong, I think there is something fascinating in all this, just wish the summary would have pointed to that aspect instead of regurgitating the so-called claimes of a breakthrough.

It depends on what you find important, remember most physics is a lot less practical than most biology. In my view people are interested in BEC because it is one of the few systems in which lots of quantum particles sit around and interact strongly, and of those, it is probably the most experimentally accessible. As for BEC in solid state quasiparticles, time will tell and I can only speculate from a position of ignorance. On the one hand it might sacrifice what I called "expermantal accessiblilty", because you have to deal with all the muck inside real solids, on the other hand a high temperature condensate made of magnons seems a lot more practical than normal condensates. Maybe it is easy to interface it to electronic control and measurement, so you can create and probe all kinds of weird and wonderful quantum states. Don't be surised if someone comes up with a paper trying to plug this as the next big thing in Quantum Computation.

Re:Please translate.

[Anonymous Coward]

The reason BECs are interesting is because you have a macroscopic number of particles behaving as a single quantum mechanical state. If you can then manipulate the BEC you've created, you have a mechanism by which you could build a quantum computer.

Since you have a macroscopic number of particles being acted upon, it's significantly less prone to interference with the environment than another variety of quantum computer scientists are trying to build with 'quantum dots'.

Re:Please translate.

[Anonymous Coward]

As a bio PhD you should be *especially* intersted in this field of BECs and quantum coherence, unless your bio sub-field consists of shuttling pap smears of gaint pandas or some such.

Quantum coherence of quasiparticles at room temps has the potential to explain the phenomenon of consciousness, dream states, subjective experience etc. Just google or wiki-search for Penrose-Hameroff.

These type of discoveries could also potentially revolutionize industrial applications in nano-tech, quantum computing etc.

Ding Dong!

[Frightening]

"Magnons are the quanta of magnetic excitations in a magnetically ordered ensemble of magnetic moments."

You have used up your stockpile of confounding-words-that-begin-with-an-M today! Please come again!

Slashdot used to be more technical like that

[Anonymous Coward]

Seriously, I had no idea Slashdot articles could be this far above my head.

Slashdot started off as a strongly science/tech-oriented discussion site, and articles that required detailed knowledge of the subject matter were common in those early days (I have a 4-digit Slashdot ID so this is first-hand).

But popularity brought in a broader cross-section of the population, and deep science and engineering knowledge is rare in the population at large. The fact that nowadays the majority of Slashdot articles are merely rehashes of some non-technical person's blog is just the editors keeping in tune with their majority audience. It's sad, but inevitable.

Re:Slashdot used to be more technical like that

[Engine]

Maybe, and maybe hopefully, slashdot will be like that again when more of the common people move over to sites like digg. I absolutly do not mind them being here, there is a lot of subjects discuss here about things that I am far from an expert in. I would not mind if the discussions were on a slightly higher level. If the submissions are a little bit above my head, I learn more from the following discussions and gain from the huge amount of collected knowledge in the slash-community. The knowledgeable people are still here, they are just drowned by the noise.

Photons in a laser are in a BEC?

[Anonymous Coward]

Umm, aren't the photons in a laser at least partly in a BEC? And, just to be clear about this, it's a condensate with stable particles, at room temperature, yadda, yadda.

Why does everybody think a hole is a particle?

[Yogurtron]

I am getting so sick of hearing people talk about a hole as if it was a particle. A hole, at least in the semiconductor sense, is where an electron should be in a valence crystaline lattice (I know I'm saying it badly, but if you know what I'm talking about, you'll know what I meant).

So this "Polarion" is said to be an electron-hole pair. You know what an electron + a lack of an electron is? AN ELECTRON. Oy.... Every time I bring this up, some other EE (yes, I am an EE) always says that, yes a hole can move and has a positive charge... No... an electron moves, causing a hole to appear somewhere. A hole has no charge, thus 1e difference from an electron. If it had the +1e everbody keeps saying, then it would be a 2e differnce between. And anyway, why talk about it having charge? It doesn't exist, therefore it cannot have charge.

Many may think I'm crazy, but a hole doesn't exist. It's very concept even being possible, because of something NOT being where it is said to be. It's existence is based off of something not existing (in the right place), I guess.

But yeah, is there some special property of holes that make them a particle that everybody keeps talking about? I just don't understand how they call something an electron-hole pair, and say that it isn't just an electron.

Re:Why does everybody think a hole is a particle?

[Anonymous Coward]

I dunno, but when you try to describe how circuits work, it tends to get tricky. Current flows from the negative towards the positive, but I have yet to see an example of a circuit whose logic 'flows' from negative to positive. It is far simpler to analyze and design under the assumption that everything flows from positive to negative for most people. I think some people try to rationalize this choice by giving the hole properties it doesn't have to have it make sense in their head.

Of course, I am not an EE... my analog knowledge is far from complete, spending most of my college time in digital design and software (and missed out on the more complex analog classes)... but this what I have seen.

Re:Why does everybody think a hole is a particle?

[wass]

I am getting so sick of hearing people talk about a hole as if it was a particle.[snip] I just don't understand how they call something an electron-hole pair, and say that it isn't just an electron.

You say you're an EE, but it seems apparent have you taken any solid-state physics classes yet. That's where you'll see the real utility in talking about holes. When you look at the band structure in the vicinity of an energy gap, from the quantum-mechanical point of view, excitations above the ground zero-temperature state are most easily expressable in terms of electron-occupations and hole occupations.

For example, in a direct-gap semiconductor, at zero temperature the valence band is fully occupied, and the conduction band is fully unoccupied. If you consider this system at finite temperatures, states in the conduction band can be occupied with finite probability, provided that a corresponding momentum-conserving state in the valence band becomes unoccupied. So sure, you can always write the ground state as the sum of all occupied states up to the fermi energy (the Fermi sea), but this gets mathematically very cumbersome. Especially for complicated materials with anisotropic band structures, etc.

It makes much more sense to redefine the ground state (the filled fermi sea) as being the vacuum state (ie, no occupations). Mathematically this makes calculations MUCH easier, as then an excitation will consist of exciting BOTH an electron (in the conduction band) and a hole (forcing a vacancy in the fermi sea). This is highly necessary for making calculations (such as conductivity, magnetization, specific heat, etc) actually possible to do. Now when you consider momentum and spin-dependent phenomena (magnetism, superconductivity, spintronics, etc) you have to carefully consider the excitations of the hole (what is it's momentum and spin). So yes, holes do map exactly to quasiparticles.

When you finally take some solid-state courses you'll see that holes DO HAVE an an effective mass (quite often not the same as the mass of the electron). They also have charge (-e), momentum, energy, and spin. Now regarding the polarons, if you're talking about complex quantum interactions, since any excitation into the conduction band requires similar 'excitation' of a hole, there is no reason to assume these two will act independently, they are of course highly coupled (conserving total momentum, spin, etc). In fact, creation of a particle-hole pair are somtimes called excitons. Now in the BEC systems under study, what reasons do you have a priori to assume that such quantized excitations would NOT consist of particle-hole pairs?

The concept of your post implies that you are intuitively understanding holes only as the lack of the electrons in a classical system. But when you consider the microscopic interactions with proper accounting for quantum mechanics and thermodynamics, your classical view falls far short of being feasibly workable. It becomes much MUCH MUCH easier to talk about holes as excitations of the Fermi sea.

And on one final note that's outside my element, by considering holes as excitations of the Fermi sea, Dirac made similar propositions in the burgeoning field of quantum-electrodynamics to propose the existence of a similar anti-electron (to the vacuum ground state being like the Fermi sea) which is the positron.

Re:Why does everybody think a hole is a particle?

[Happy Tinfoil Cat]

Electrons get all hot and bothered and fly off the cathode of my TV tube striking the phosphor which emits photons. Of course the opposite could be true. Darkons may collect on my screen until electron holes get sucked into the cathode of my TV tube but somehow it seems backwards. ;^)

Re:Why does everybody think a hole is a particle?

[Yogurtron]

Thank you Wass, for the very well thought out, and researched (or at least known from previous study) post about this. I am only a senior at college for a BS in EE, so I definitely don't know everything about it yet. As far as I've been told, holes were just an abstraction of a lack of an electron in the valence band, and used (at best) as a convinience in doing calculations dealing with semi-conductors and the like.

So I understand the first part of your post was backing one of my points, that it is an abstraction to make calculations much easier.

As for the rest, it seems that due to quantum probability waveforms from the surrounding particle, it creates a particle-esque signature of sorts, where the hole is, giving particle-ish properties to the empty space where the hole is? I am also lacking in my quantum physics understanding, only taken the first class in it so far (special relativity to begining quantum mechanics with tunneling and blackbody radiation), so that may be an incorrect assumption, but please clarify if it is, heh.

If my interpretation is correct though, that would make just about every form of matter, at least in solids, have quasi-particles forming all around it due to quantum fluctuations. Granted I can't dispute that, but I would think that having such particles constantly being created in all solids (and probably to a lesser extent gasses and liquids, at least for hole-esque quasi-particles) would have had a lot more obvious implications or interactions seen on a daily basis.

But I digress, thank you for explaining why people think/say holes are particle-ish, as opposed to my colegues here that just say, "They move and have charge" without backing it up.

Re:Why does everybody think a hole is a particle?

[wass]

It's not as useful think about the electron's or hole's location, but much more useful to talk about its momentum (or other useful 'good quantum number'). If you think of the electrons as a gas, without strong interactions between each other, they form a a continum of states, each state has momentum (hbar*k) and energy (p^2/2m) where k is the wavevector, which is quantized as a function of your sample's size. (you hopefully recognize that expression as the kinetic energy, where we're assuming the lattice potential energy, as well as electron interaction potential energies are weak and can be ignored.) In simple models for a semiconductor, this is a valid-enough approximation except the potential energy contributions are significant at the Brillouin Zone edges, where the quadratic energy dependence on 'k' flattens out, to form the so-called energy gap separating valence and conduction bands.

In a 3-D crystal, your momentum is a 3-D vector, and therefore 'k' is a vector. Electrons have two available spins, up and down (denote spin by quantum number s=+1 and s=-1). So in the ground state, no two electrons in the system can have the same set of quantum numbers. This means each of the 10E23 electrons has a different 'k' and 's'. The ground state can be thought of as adding electrons to the system by applying the quantum 'creation operator', adding an electron of momentum 'k' and spin 's'. So the Fermi Sea is the state producted by applying the creation operator over ALL allowable k (zero to the 'k' associated w/ the Fermi energy), and over all spins. Now if you want to keep doing this integral from the vacuum state just for simple excitations of a few electrons, you are being ridiculous. Especially when you deal with non-trivial lattice potentials as well as strong electron interactions, the integrals become VERY difficult to solve. But you can always think of small excitations from the ground state in the standard electron-hole picture, which gets quite easy, especially since you can model things as Taylor expansions about the ground state where gaps can be modelled as quadratic, etc.

A thermal or other excitation above this ground state will consist of BOTH annihilating an electron with some given 'k' and 's', and then creating it with some other 'k' and 's'. Each of these operations is done with the quantum-mechanical creation and annhilation operator, which don't necessarily commute with each other (just like position and momentum operators don't commute). This leads to nontrivial quantum phenomena.

Due to the periodic lattice structure (and hence periodicity in momentum space, along with the various Brillouin Zones), there are different allowable energies for a given 'k'. So it's MUCH EASIER to model interactions from the Fermi Sea ground state as both exciting a hole and also exciting an electron, each with their associated 'k' and 's'. Such excitations can come from a variety of sources, such as magnetic interactions, lattice interactions, etc, and become very interesting and difficult to capture. Eg, it took about 50 years to get the BCS model of superconductivity at this level after discovery of superconductivity in 1911.

But anyway, this is why it's highly useful, and thus important, to consider holes. When you run through the details in this way you see holes have an effective mass, momentum, spin, etc. And they certainly can and will interact with the excited electrons as well.

Anyway, I hope this helps, and that you don't get so accusatory when people talk about holes, because physically and mathematically it makes much sense to talk about holes as excitations. Now I have to get to work, I'm spending too much time writing these things out.

Re:Why does everybody think a hole is a particle?

[Yogurtron]

Addendum:
I read up a bit more on the excitons and quasiparticles. Quasiparticles are abstactions of particles, it seems. They don't actually exist but make calculations much easier, so I calculated what happens with the quasiparticle, and figure out how the rest of the particles around it are affected, as opposed to figuring out what is going on with each individual other particle around it.

That's all well and good, but that is still an abstraction of a particle, not a particle. It's an idea that explains things easier, but never actually proves it itself exists.

This explanation makes a quasiparticle sound like it needs many other particles around it, at least more than 2 for it to be of any use. Thus an polaron makes little since, being ONE electron, and one hole. It doesn't mean a hole exists as any true entity, it just means that the electron is not reacting as we think it should, and thus more study should go into WHY it is acting that way. Not to say we can't use hole's and other quasi-particles to make things easier in calculation, but to say this demi-particle is actual a physical (or even probabilistic) entity, is silly.

I read a bit on the excitons, and it makes some more sense, but it just says that the electron binds with its own hole. It doesn't explain how, it just says that it is attracted to it. The electron isn't attracted to the hole, it is attracted to the proton it just left, leaving said hole. And even IF it somehow is attracted, how does it bind to an abstraction created by itself. And even if THAT was possible, what stops this electron from being ejected, making a hole, binding to it, having that exciton then ejected, making a new hole, binding to it, and repeating until it has nullified all of its energy due to it binding with multiple holes? (It said that the bound state of electron and hole is slightly less energy than the electron).

So in the end, I'm still confused, it seems that a hole and quasi-particles are just abstractions of particles to explain phenomenon in an easier to calculate manner. However other events suggest that these quasi-particles are legitimately particulate, to the point that one can make substances (materials, bound states, whatever, i'm not sure what you cal them) with them, like an exciton. It is either an abstraction, or it is not, yet this being both real and a convinence makes it, in and of itself, a quasi-quasiparticle... as silly as that sounds.

Anyway, so yeah, how does it exist as a demi-particle, both as a mathematical convience that doesn't quite exist, but does in other senses?

Re:Why does everybody think a hole is a particle?

[Starker_Kull]

I am getting so sick of hearing people talk about a hole as if it was a particle. A hole, at least in the semiconductor sense, is where an electron should be in a valence crystaline lattice (I know I'm saying it badly, but if you know what I'm talking about, you'll know what I meant). So this "Polarion" is said to be an electron-hole pair. You know what an electron + a lack of an electron is? AN ELECTRON. Oy.... Every time I bring this up, some other EE (yes, I am an EE) always says that, yes a hole can move and has a positive charge... No... an electron moves, causing a hole to appear somewhere. A hole has no charge, thus 1e difference from an electron. If it had the +1e everbody keeps saying, then it would be a 2e differnce between. And anyway, why talk about it having charge? It doesn't exist, therefore it cannot have charge.

But, as you are no doubt aware, in a conductor where the outer valence electrons are so weakly held that they are approximately free to drift within the boundaries of the material, if a particular atom at a particular time has one less electron bound to it than it has protons in its nucleus, then as a whole, it is positively charged - and it tends to attract any 'free' electrons in the vicinity. As one of these 'free' electrons has to come from somewhere, the somewhere (being another atom) is now short an electron. Thus, the location of the positive charge has moved. So, in a material, talking about positive holes moving, having a certain density and so forth is quite reasonable.

Many may think I'm crazy, but a hole doesn't exist. It's very concept even being possible, because of something NOT being where it is said to be. It's existence is based off of something not existing (in the right place), I guess. But yeah, is there some special property of holes that make them a particle that everybody keeps talking about? I just don't understand how they call something an electron-hole pair, and say that it isn't just an electron.

Because electrons aren't dealt with in a vacuum. If you took a small ball of some element, say carbon (Make it 12 g - one mole of the stuff), and it was 'missing' only 1 electron in 1,000,000,000 atoms, our little ball of carbon would have a charge of .1 millicolumbs. If you held this little ball about a centimeter away from its missing electrons, they would attract each other with a force of about 10,000 N - or roughly the weight of a ton! The balance between the number of electrons and the number of protons in a material rarely deviates by more than 1 in 10^15 particles in practice. So, keeping track of the 'holes', since they match the number of electrons to an exquisite level of precision, even in conductors carring hundreds of amps of current, is a very reasonable model of what occurs.

As for whether 'holes' are real, read up on what Dirac has to say about electrons sometime - you can google it.

Re:Why does everybody think a hole is a particle?

[bodan]

I'm not much above you in my understanding of these things, but there is in the comments above a very good (easy to visualize) analogy to the "electron hole" idea: bubbles in a liquid. They're all really places where there is no liquid, but it's still easier to think of them as "particles". They can move in the liquid, they have a sort of "negative mass" because they float to the surface in a gravity field, unlike something with positive mass that falls (it's all relative to the system you're looking at, somewhat like the centrifugal force), they can split or combine (with "negative mass" conservation and probably impulse conservation), they can "vibrate in volume" (grow or shrink as the pressure changes).

The astute reader will notice that bubbles are not really empty, there's gas inside that makes them "real". Then again, the EM field plays an analogue role for electron holes. It's just an analogy, don't start nitpicking for differences; but it is very useful to visualize the issue.

Re:Why does everybody think a hole is a particle?

[Anonymous Coward]

What is a charged particle? a collection of degrees of freedom that behave like one. I.E. be localizable, or move (propagate) according to the laws of QM when a charge is applied. A hole is such a collection of degrees of freedom.

It's not "real"? What's your definition of real then? Atoms are not real they are just a bunch of electrons and neutron and protons which happen to be spatially localized in a certain region, right? So please stop talking about Atoms when everybody KNOWS that they are not actually real! And all this talk about Ions having charge +1, +2, etc... that's a load of bull! An Ion has a very complicated structure, the electric field will have multipole moments all over the place! Sure to first order approximation an Ion might act like it has an integer charge, but it really doesn't.

Right?

fh

I shot my...

[sweetnjguy29]

...Bose-Einstein Condensate all over her face. Boy, was she cold after!

No, the cat does not "got my tongue."

[Impy the Impiuos Imp]

> Just in case you need a brush up on BEC, like I did, check out the Wikipedia article on Bose-Einstein condensation

Ok, IANAP, but I thought the BEC was the result of supercooling atoms until their temperature, and hence momentum, was virtually 0. Because of quantum conjugate pairs, their position's uncertainty therefore must skyrocket. This bizarre, near-macroscopic "thing" was the "condensate". That Wikipedia article mentions none of this. Am I even more clueless than I already know I am, or is the article just poorly written, like a computer reference manual, only useful to people who know the subject backwards and forwards?

Correction

[wass]

Oops, seemingly-minor correction, but in the 2nd paragraph I should have said : "A mode will oscillate at a specific frequency, however. If you write the 'equations of motion' for all atoms in the crystal in 'matrix' form, the modes would correspond to the 'eigenvectors' of that matrix."

Eigenvalues are scalars, eigenvectors are vectors. In this case the eigenvectors would describe the motion of each of the atoms in the crystal.

Re:Correction

[RobertB-DC]

Oops, seemingly-minor correction, but in the 2nd paragraph I should have said : "A mode will oscillate at a specific frequency, however. If you write the 'equations of motion' for all atoms in the crystal in 'matrix' form, the modes would correspond to the 'eigenvectors' of that matrix."

Dude... I was so out of my depth, you could have said "the modes would correspond to the 'Keanuvectors' of the Matrix" and I would have been like, "Woah".

Seriously, though -- like the other non-troll respondents to your message, I want to thank you for making Slashdot a smarter place.

Re:Solid State? Good Info

[bhairon]

I really appreciated the information. My dad always taught me to hang out with people smarter than me, because that would make me smarter in the long run. He taught me to never be afraid to "look something up". That's probably why people understand what I say just about as much as people understand your topic. It was great information, and I followed it well. Glad to have you on board.

Back in the "Good Old Days" ...

[Anonymous Coward]

Slashdot started off as a strongly science/tech-oriented discussion site, and articles that required detailed knowledge of the subject matter were common in those early days (I have a 4-digit Slashdot ID so this is first-hand).

I remember this too.

I've been posting on Slashdot since before they had these newfangled "user accounts". I didn't see the need for them then, and I don't now: that's why I post as an AC.

Interestingly, shortly after the user accounts were created, I found this cool new user who posted a lot of wierd things, but some very, very smart things as well. His name was "Anonymous Coward". Over time, the number of kids arguing with PhDs over their field of expertise tended to weed out the experts on slashdot, and now it's mostly just 15 yr old kids, and a few cranky old holdouts like me.

Room Temp BCEs and consciousness

[Anonymous Coward]

Could it be that Quantum coherence of quasiparticles at room temps has the potential to explain the phenomenon of consciousness, as proposed by Penrose, Hameroff and others (www.quantumconsciousness.org/ and also the movie What The *bleep* Do We Know)