Physicists seek to put one thing in two places

World Science ^ | 25 Sept 2006

[snarks_when_bored]

Physicists seek to put one thing in two places

Sept. 25, 2006
Special to World Science  

Physi­cists say they have made an ob­ject move just by watch­ing it. This is in­spir­ing them to a still bold­er proj­ect: put­ting a small, or­di­nary thing in­to two places at once.

It may be a “fan­ta­sy,” ad­mits Keith Schwab of Cor­nell Uni­ver­si­ty in Ith­a­ca, N.Y., one of the re­search­ers. Then again, the first ef­fect seemed that way not long ago, and the sec­ond is re­lat­ed.

The gray sliv­er reach­ing from top to bot­tom, slanted in the im­age, is a na­no­me­chan­i­cal re­s­o­na­tor, a sub-mi­c­ro­s­co­pic de­vice that can vi­brate like a pia­no string. The im­age was tak­en with a scan­ning el­ec­tron mi­cro­scope and col­or­ized. (Cour­te­sy Cor­nell Uni­ver­si­ty)

The re­search comes from the edge of quan­tum me­chan­ics, the sub­mi­cro­sco­pic realm of fun­da­men­tal par­t­i­cles. There, things be­have with to­tal dis­re­gard for our com­mon sense.

They can show signs of be­ing in two places at once; of be­ing both waves and par­ti­cles; of tak­ing on some cha­r­ac­ter­is­t­ics on­ly at the mo­ment these are meas­ured; and of act­ing syn­chro­nous­ly while far apart, with no ap­par­ent way to com­mu­ni­cate.

Al­though these ti­ny build­ing blocks of our uni­verse do this, the re­l­a­tively huge things we see eve­ry day don’t. The un­can­ny be­hav­ior fades the big­ger a thing be­comes.

This is be­cause when quan­tum en­t­i­ties are com­bined to make or­di­na­ry ob­jects, the rules go­vern­ing each com­po­nen­t’s be­ha­v­ior add up to pro­duce new rules. These in­c­rea­s­ing­ly re­sem­ble the laws of our fa­mi­l­iar world as more ad­di­tions take place.

But just how big can some­thing be and still show signs of slip­ping back in­to its quan­tum-me­chan­i­cal na­ture?

Schwab and his col­leagues de­cid­ed to find out. In work de­s­cribed in the Sept. 14 is­sue of the re­search jour­nal Na­ture, they built a de­vice co­los­sal by quan­tum stan­dards: about nine thou­sandths of a mil­li­me­ter long, con­tain­ing some 10 tril­lion atoms.

The ob­ject was a sliv­er of alu­mi­num and a type of ce­ram­ic, fixed at both ends but free to vi­brate like a gui­tar string in be­tween. To meas­ure its move­ments, the sci­en­tists set near­by a ti­ny de­tec­tor called a su­per­con­duct­ing sin­gle elec­tron tran­sis­tor.

They found that ran­dom mo­tions of charge-carrying par­ti­cles, elec­trons, in the de­tec­tor em­a­nat­ed forc­es that af­fect­ed the me­tal­lic sliv­er. When the de­tec­tor was tuned for max­i­mum sen­si­tiv­i­ty, these forc­es slowed down the sliv­er’s shak­ing, cool­ing it as a re­sult. This ef­fect, Schwab said, is a ba­si­cal­ly quan­tum-me­chan­i­cal phe­nom­e­non called back-action, in which the act of ob­serv­ing some­thing ac­tu­al­ly gives it a nudge.

Back-action in quan­tum me­chan­ics al­so makes it im­pos­si­ble to know a par­ti­cle’s ex­act lo­ca­tion and speed si­mul­ta­ne­ous­ly. This lim­i­ta­tion is called the un­cer­tain­ty prin­ci­ple. A com­mon ex­am­ple: meas­ur­ing place and speed re­quires some de­tec­tor that can “see” the par­ti­cle. But this in­volves bounc­ing a light wave off it, which gives it a ran­dom push.

“We made meas­urements of po­si­tion that are so in­tense—so strongly cou­pled—that by look­ing at it we can make it move,” said Schwab. Nor­mal­ly, such mo­tion would­n’t cool an ob­ject. But the mo­tion can be such as to op­pose on­go­ing move­ments and slow them down. This re­duces an ob­ject’s heat, which is just the jig­gling of par­ti­cles in it.

If back-action ap­plies such a large item, Schwab rea­sons, may­be that can al­so be true of oth­er quan­tum-me­chan­i­cal rules. Particularly in­tri­guing, he said, is the superpo­si­tion prin­ci­ple, which holds that a par­ti­cle can be in two places at once.

A classic ex­am­ple is the shoot­ing of light par­ti­cles, called pho­tons, through two slits in a bar­rier. Past the slits, they will be­have as if they were waves. This alone is no sur­prise: it’s a well-known quan­tum me­chan­i­cal phe­nom­e­non that par­ti­cles can par­a­dox­i­cal­ly act like waves in some sit­u­a­tions. The pho­tons’ wav­i­ness then makes them “in­ter­fere” with each oth­er. In oth­er words, they make pat­terns like those seen when you toss two peb­bles in a pond, and the rip­ples they send out overlap.

When the waves passing the two slits mu­tu­al­ly in­ter­fere, the pat­tern be­comes vi­si­ble if you set up anoth­er wall where the par­ti­cles can land. There, al­ter­nat­ing bright and dark stripes ap­pear.

But bi­zarre­ly, this works even if you fire just one pho­ton at a time through the slits. You can see the ef­fect then by put­ting pho­to­graph­ic film on the land­ing wall, so each pho­ton leaves a last­ing mark. Keep fir­ing pho­tons, and the marks grad­u­al­ly add up to make the stripes again.

It’s as if each pho­ton is in­ter­fer­ing with it­self—that is, go­ing through both slits si­mul­ta­ne­ous­ly. This al­so works for big­ger par­ti­cles, up to a point. But what point? Schwab wants to know. “We’re try­ing to make a me­chan­i­cal de­vice be in two places at one time. What’s real­ly neat is it looks like we should be able to do it,” he said. “The hope, the dream, the fan­ta­sy is that we get that superpo­si­tion and start mak­ing big­ger de­vices and find the break­down.”

In a com­men­tary in the same is­sue of Na­ture, Mi­chael Roukes of the Cal­i­for­nia In­sti­tute of Tech­nol­o­gy in Pas­a­de­na, Calif., wrote that Schwab’s work with the cool­ing is part of an emerg­ing field, quan­tum electrome­chan­ics. This, he added, fo­cus­es on sub­mi­cro­scop­ic de­vices called nanome­chan­i­cal sys­tems, “poised mid­way be­tween two seem­ingly an­ti­thet­i­c do­mains” of size: fun­da­men­tal par­ti­cles at one end, the ob­jects of eve­ryday life at the oth­er.

[snarks_when_bored]

Let the puns begin...

[snarks_when_bored]

Let the puns begin...

[Wage Slave]

Trying hard to understand the explanation of how looking at something can actually nudge it. Where do the electrons come from when we look at something? Yes, I know I am a moron. Very interesting post.

[Brilliant]

"Physi­cists say they have made an ob­ject move just by watch­ing it."



Physicists have a habit of describing what they have discovered in ways that interest the public, but are not really accurate--at least not accurate if you would ask the average guy.

If you've got a particle, you can't just "watch it." It's too small. You use a probe to see if it's there. Or you might shine a light on it, if it's big enough. You use high tech equipment to measure its charge, and that will give away its position.

Of course, when you do any of those things, the particle is nudged a little bit. When you touch it with a probe, shine light on it, or test its charge, it moves.

It would be more accurate to say that they are making it move by "touching it," but then that would not be such a big headline.

[Brilliant]

It's not the looking at something that moves it. See my earlier post. What moves it is that you can't see it unless you bounce something off it, like light or electrons, or something else. Your eye detects the light that comes from the object, but first the light has got to reflect off the object.

[SlowBoat407]

Trying hard to understand the explanation of how looking at something can actually nudge it.

Wink wink, nudge nudge.

[SlowBoat407]

Trying hard to understand the explanation of how looking at something can actually nudge it.

Sometimes I can look at a woman and actually move her 10 feet or more... away from me.

[snarks_when_bored]

Trying hard to understand the explanation of how looking at something can actually nudge it. Where do the electrons come from when we look at something?

Electrons interact with other electrons via the electromagnetic interaction, which is mediated by photons. If no photons are exchanged, no interaction take place (ignoring virtual photons and tunneling subtleties). So, essentially, if no photons are exchanged, nothing is seen, and if photons are exchanged, a disturbance in the motion of the seen (and the seer) takes place.

[Loyalist]

[Wage Slave]

Okie dokie. Got it. Thanks!

[Wage Slave]

LOL!

[Wage Slave]

I have the same mystical power over men.

[HiTech RedNeck]

looking for love in both the wrong places

[Hand em their arse]

What time did you want me over again? : )

[saganite]

Physi­cists say they have made an ob­ject move just by watch­ing it.

I can do that after several bourbons. I can even put the same object in 2 or 3 places at the same time. Nothing new here.

[Wage Slave]

hmmmmm.....are you an auto mechanic?? ;)

[Wage Slave]

Can you cook?

[.cnI redruM]

Bill CLinton seems to have done that all the time. He also could see all three sides of a two-sided issue. I think we should give him a Nobel Prize for Physics and let him mount it in the museum down in Hope, Ark.

[snarks_when_bored]

hmmmmm.....are you an auto mechanic?? ;)

No, a voyeur. (laugh)

[Rummenigge]

works even without photons or any particle exchanged with a detector.

If you obeserve interference of a single photon with itself on a double slit it is strange enough - because it seems to contradict the fact that it is only ONE photon. But even more strange - if you detect which slit it DID NOT take - interference will brake down.

Either you know, where a particle is a distinct time OR you know what impulse it has (speed, mass and direction) that's a LAW not a desricption of the unfitness of scientist or technicians to measure more precise.

Seeing the interference defines wich impulse the photon had so you can't have that AND know where it was at a certain time - even if you have found that out by looking where it NOT has been leaving it only one possibility.

A more abstract explanation might be given by string theory.

[tm61]

but can they put things on top of other things?

[SlowBoat407]

That would confuse the cat (Schroedinger's Cat, of course). There, I've run rings around you logically!

[true_blue_texican]

It would be more accurate to say that they are making it move by "touching it,"

Very good point!

[Lazamataz]

Physi­cists say they have made an ob­ject move just by watch­ing it.

(Laz looks at his crotch)

[Red Badger]

"Physi­cists say they have made an ob­ject move just by watch­ing it."

Hell, my mother could do that!............."Take out the garbage"....."Mow the lawn"......etc......

[Oberon]

I have the same mystical power over men.

[droning monotone] ...she has the same mystical power over men...

[JamesP81]

Sometimes I can look at a woman and actually move her 10 feet or more... away from me.

Ahh, yes, I possess this same power as well. Perhaps we are strong in the force?

[headsonpikes]

All I want to know is - does the Cat live?

[SlowBoat407]

Perhaps we are strong in the force?

My brother, we are strong in something.

[snarks_when_bored]

All I want to know is - does the Cat live?

Yes and No.

[grey_whiskers]

All I want to know is - does the Cat live?

Did Schroedinger ever have to change his kitty litter?

[onedoug]

A new variation of the old boson-fermian trick?

[Larry Lucido]

Physicists seek to put one thing in two places

Big deal. So do porn stars.

[jwalsh07]

Sounds almost, well, Newtonian.

[headsonpikes]

Yes and No.

And here I thought it was Yes and/or No. This new sort of physics is obviously less inclusive.

[Eastbound]

"This ef­fect, Schwab said, is a ba­si­cal­ly quan­tum-me­chan­i­cal phe­nom­e­non called back-action, in which the act of ob­serv­ing some­thing ac­tu­al­ly gives it a nudge."

Ahah! Eureka! Forsooth! Verily! Is there a possibility that a tree falling in the forest makes no sound unless someone is listening?

[snarks_when_bored]

All I want to know is - does the Cat live?

Did Schroedinger ever have to change his kitty litter?

See post #30.

[Pride in the USA]

ping

[snarks_when_bored]

(laugh)

[KarlInOhio]

Physicists seek to put one thing in two places

Which is why Schrödinger used cats for his famous thought experiment. A cat could be meowing in front of her food bowl, knocking things off of her favorite shelf and getting under your feet simultaneously. Cats are also good at quantum tunneling where you can block all paths from point A to point B but the cat still moves between them.

[Twinkie]

Okay. I have noticed that my dog, Dixie, is IN TWO PLACES AT THE SAME TIME! I have hesitated to mention it to anyone, but this discovery explains it and makes it sort of okay to reveal it. - Well, anyway, during the day when I'm at the back door and look out - there stands Dixie waiting for me to pass her a treat out the back door. Then in a minute or so, when I move to the side door and look out, THERE STANDS DIXIE, tongue hanging out waiting for me to hand her out another slice of baloney or dog biscuit or something. There is NO WAY Dixie could run fast enough to be at both doors so soon. It is weird. In fact, her dry kibbles bin empties out so fast one would have to think there really are TWO Dixies living here.

And that's the way it is . . just another day here at Black Rock River Ranch, and such a comfort that science is finally explaining the strange happenings here at the ranch.

[NicknamedBob]

"... made an ob­ject move just by watch­ing it."

Not really. Simply an admission that for very tiny objects, the light that illuminates them can also give a tiny push.

I don't suppose they are willing to claim they can make an object move by watching it in the dark.

[Junior]

I once knew a guy named Vinnie who ended up in several places at once. In small, green, trash bags...

[Erasmus]

The gray sliv­er reach­ing from top to bot­tom, slanted in the im­age, is a na­no­me­chan­i­cal re­s­o­na­tor, a sub-mi­c­ro­s­co­pic de­vice that can vi­brate like a pia­no string. The im­age was tak­en with a scan­ning el­ec­tron mi­cro­scope and col­or­ized.

BZZZZT. PARITY EXCEPTION IE00007E00013A. GUTEN ABEND.

[dangerdoc]

bump

[Erasmus]

Who do you think he is, a bloody Doctor Bronowski?????!

[Boiler Plate]

Nothing is fundamental. There is always something smaller.

[snarks_when_bored]

Nothing is fundamental. There is always something smaller.

Maybe it's turtles all the way down?

[jpsb]

is it not a fundamental law of physics that no object can be in two places at the same time?

[MonroeDNA]

I can make guys on the golf channel miss a putt, just by thinking.