backtop


Print 32 comment(s) - last by marsovac.. on Jan 15 at 1:22 PM

Lasers, magnetic fields coax lattice-arranged potassium gas into a bizarre state

Scientists have demonstrated a feat that your physics teacher may have told you was impossible -- they have created a material with a temperature below absolute zero.  And the world below absolute zero is an unusual place indeed.  

I. It's a Very, Very Mad World

Atoms float upwards, ignoring gravity.  In a phenomenon that theoretical physicists believe mimic "dark energy", the atoms even stabilize in conditions that would normally crush inwards.  It's as if gravity itself is being overridden and energetic arrangements that would normally create instability, instead stabilize.  In short, we've entered the Twilight Zone of particle physics.

Massachusetts Institute of Technology professor Wolfgang Ketterle was a pioneer in the field of negative absolute temperatures.  He remarks, "[With negative absolute temperatures it is] as though you can stand a pyramid on its head and not worry about it toppling over."

The MIT professor in a new interview with Nature lauds the new work by Ulrich Schneider of Munich, Germany's Ludwig Maximilian University and colleagues.  In the work Professor Schneider demonstrates the first-ever peer-reviewed instance of a negative absolute temperature material breaking the absolute zero behavior.

The work began with Professor Schneider creating a peculiar quantum gas, using lasers and magnets.  Composed of potassium atoms the gas was arranged into a lattice structure.  A radical adjustment in the magnetic fields switches the atoms from the lowest energy state possible to the highest energy state possible.

Potassium atoms
The quantum gas is composed of potassium atoms. [Image Source: MaterialScientist]

Here is where the special behavior takes hold.

Normally the stabilizing repulsion of the original configuration would be replaced with an immense attraction, causing the system to collapse and implode.  But thanks to the trapping lasers, the lattice instead remains stable in the new super-energized state.  Comments Professor Schneider, "This suddenly shifts the atoms from their most stable, lowest-energy state to the highest possible energy state, before they can react.  It’s like walking through a valley, then instantly finding yourself on the mountain peak."

The result is a gas that by the formal definition of the Kelvin scale is a few billionths of a degree Kelvin below absolute zero (0 K).

II. Negative Absolute Temperatures?  That's Really Cold, Right?

But don't be confused.  The below-absolute-zero system is not cold.  It is in fact very, very hot -- hotter than any positive Kelvin system.  In cooler positive temperature systems, the numbers of particles in low-energy states outnumber those in high-energy states, giving rise to the formal quantum mechanics definition of temperature.  Typically entropy pushes atoms to occupy lower energy states, on average.

Lord Kelvin
Lord Kelvin's temperature scale is formally based on probability, not necessarily heat.
[Image Source: Unknown]

But in certain specialized quantum mechanical systems, the entropy actually decreases as the system energy (and "heat") increase, giving rise to a negative quantum temperature.

In other words, to understand this wild breakthrough, you must abandon your traditional notions of negative being cold and positive being hot and think in quantum terms.  This isn't your high school physics teacher's negative temperature.  It's a bizarre exercise in inverted entropy.

Could such a state be possible for the faster-than-expected expansion of the universe (a phenomena cosmologist attribute to so-called "dark energy", a poorly understood mechanism)?  Professor Schneider argues the idea is worth exploring.  He comments, "It’s interesting that this weird feature pops up in the Universe and also in the lab.  This may be something that cosmologists should look at more closely."

Negative temperature materials could be a boon to both theoretical particle physics and quantum computing.  But much work needs to be done to understand their bizarre new spin on physics.

The work by Prof. Schneider and his colleagues was published in the highly prestigious peer-reviewed journal Science.

And if that makes your brain hurt, take a break and read the classic college urban legend of a physic professor's exam question of whether hell is exothermic or endothermic and his student's epic response.

Sources: Science, Nature



Comments     Threshold


This article is over a month old, voting and posting comments is disabled

RE: As long...
By Misty Dingos on 1/9/2013 7:51:01 AM , Rating: 1
Just bleeping great.

New law of thermodynamics: Things get cold until they get hot.

Try to explain that to a class of highschool kids that are more interested in an X-Box or the girls (or boys) X-box sitting next to them. The more complex and less sensical our science becomes the fewer and fewer people will have an understanding of it. These fewer and fewer people will be the only people that understand how things actually function in the world. The ever growing number of dolts will eventually overwhelm us all and the world collapses into anarchy and we will enter a new dark age brought about by Honey BooBoo and science that can't be explained.

I give us two generations at most. Meanwhile you can watch the end of humanity from your lounge chair while eating food that never came from a farm while watching Idiots on Parade on 600+ channels of Ultra-High Definition "reality" programing. While you post pictures of your cat to Facebook.


RE: As long...
By deksman2 on 1/9/2013 9:43:50 AM , Rating: 2
The educational system has been garbage for a LONG time now.
Its sorely outdated, based on repetition (which is inefficient), it doesn't expose anyone to relevant general education, nor does it prompt children and adults to think in a critical capacity or to be problem solvers.

Couple it with society that actively portrays numerous subjects as 'hard' or 'difficult to understand', and you wonder why people don't understand anything?

We need to completely overhaul the environment/society in which we live in.
Its possible/doable.
While I will agree with the premise that a lot of people don't do terribly constructive things on their computers... they (as well as everyone else who have access to the Internet) are also exposed to even more information than before, and are beginning to understand that something is wrong with society.

Science going forward and discovering that certain theories no longer apply or can be bypassed, bent if not broken is how it all works.
We need to get rid of the outdated mentality and create an emergent society where social awareness is in line with our latest scientific knowledge.

Right now, our technology is 60 to 100 years BEHIND of practical application of our scientific knowledge (due to the profit motive and the inherently limited monetary system - which became useless 100 years ago).

As for laws of thermodynamics... they were based on relatively old knowledge.
And while I will agree that some it may apply, people cling way too much to 'laws' and 'rules' when science was based on the premise that everything and anything is essentially subject to change at any given time.
Evidence is not proof, nor is correlation proof of causation.

Afraid of questioning the well established theories and 'facts' and being painted as a 'moron'?
Don't be... because, our society couldn't develop if we didn't do that.
Concerning oneself with other people's perception is pointless.
Society is often times more wrong that it is correct... and historically, society underwent large changes.

Its up to us to be the change in the world we want to see... otherwise, nothing will happen.


RE: As long...
By Misty Dingos on 1/9/2013 10:45:08 AM , Rating: 3
In a society where ignorance is seen as virtue, where language is seen as restrictive by many and racist by some, you can tilt at windmills all you want. But Ignorance is still king.

Look at the average post made at this site. An argument can be made that people that post here are likely to be more educated and are obviously more interested. Yet the average post is simply a series of attacks based on emotional responses either wished for by the poster or dumped on them by the readers.

Even if the subject article is flawlessly written, has journalistic merit and is solidly researched opposition will argue that the skies are pink, whales have the answers and trees walk the earth if it means they have to accept that their view point may actually be wrong.

If you can't get cogent arguments from highly educated and interested people how are you ever going to educate the average world citizen in the basics of science, reason and thinking?

I wish you well Don Quixote.


RE: As long...
By Kurz on 1/9/2013 11:08:12 AM , Rating: 2
The fact you downplay the profit motive and Monetary system almost leads me to discredit everything else you said.


RE: As long...
By deksman2 on 1/10/2013 1:49:25 PM , Rating: 2
The profit motive and the monetary system ARE part of the problem (a huge part actually).
Nobody asks a question: 'do we have the resources and technology to make something happen' (you know, the things we actually NEED) - to which the answer is practically always 'yes'.
Instead, people usually ask: 'how much does it cost and is it profitable?'.

This is why a re-education of society is required.
Social awareness has to be brought up to our latest scientific knowledge.
So many people claim things are 'impossible' and the main reason they do so is due to lack of exposure to relevant general education and critical thinking.

Right now, people are prone to being manipulated and used because their information is limited to specific sources/opinions.
Questioning pre-established things is discouraged because today, everything is monetized, and unless its profitable or usable within the current structure, it won't be discredited anytime soon, and those who try to at least encourage others to take into consideration the possibility that established notions could be in error, they are sooner ridiculed (because society or 'accredited' individuals are never considered to be prone to making mistakes).

Multi-billion dollar industries in some cases would end up going under if the underlying theories that allowed their existence came into question.
You have any idea how many people could lose their jobs in such a scenario?

There is no conspiracy necessary in a system where common interests converge on a daily basis (in capitalism, they converge on a daily basis).

I'm just appalled that numerous people are AWARE that these things are happening and they couldn't care less (at least until they start losing their confidence in the system and those they elected, and everything they have - which is when they start to 'care' - of course, by the time that happens, its already too late).


RE: As long...
By MZperX on 1/9/2013 12:06:29 PM , Rating: 2
I could follow along okay until you dropped this gem: "due to the profit motive and the inherently limited monetary system - which became useless 100 years ago"

I stopped reading at athat point. Please start with the nonsensical part of your post next time, so we can all move along without wasting time. Thx!


RE: As long...
By marsovac on 1/15/2013 1:22:09 PM , Rating: 2
Care to argument?

The monetary system as it is requires economic crisis to happen in cycles (inflation is a byproduct of the system, since fictive capital is created [capital without any economic value behind it]). Crisis that basically stop progress for a decade. Then for 20 years you have progress going on unnaturally fast.

But thats is not stability, thats something that creates beliefs in the system while it is going well and tries to keep as many believers when it is going bad.

But stable progress requires stability. Stability in the order of many decades.

If you start a project which after a few years gets canceled during the crisis which could have led to a breakthrough in later years, you have hindered progress much more than you will get back during the good years.

These depression/economic crisis cycles do much worse than you think.


"This is from the DailyTech.com. It's a science website." -- Rush Limbaugh














botimage
Copyright 2014 DailyTech LLC. - RSS Feed | Advertise | About Us | Ethics | FAQ | Terms, Conditions & Privacy Information | Kristopher Kubicki