Negative temps and machines "more than 100% efficient" - 4 Jan 2013 in major Journal

[PhysicsProf]

"The scientists detailed their findings in the Jan. 4 issue of the journal Science."

Major publication, using language we are used to in this community, for example:

This unusual advance could lead to new engines that could technically be more than 100 percent efficient, and shed light on mysteries such as dark energy,

Science gets colder than absolute zero

By Charles Choi

Published January 04, 2013

LiveScience

negative-temperature-atoms.jpg

When an object is heated, its atoms can move with different levels of energy, from low to high. With positive temperatures (blue), atoms more likely occupy low-energy states than high-energy states, while the opposite is true for negative temperatures (red). (LMU / MPQ Munich)

Absolute zero is often thought to be the coldest temperature possible. But now researchers show they can achieve even lower temperatures for a strange realm of "negative temperatures."

Oddly, another way to look at these negative temperatures is to consider them hotter than infinity, researchers added.

This unusual advance could lead to new engines that could technically be more than 100 percent efficient, and shed light on mysteries such as dark energy, the mysterious substance that is apparently pulling our universe apart.

An object's temperature is a measure of how much its atoms move — the colder an object is, the slower the atoms are. At the physically impossible-to-reach temperature of zero kelvin, or minus 459.67 degrees Fahrenheit (minus 273.15 degrees Celsius), atoms would stop moving. As such, nothing can be colder than absolute zero on the Kelvin scale.

Bizarro negative temperatures

To comprehend the negative temperatures scientists have now devised, one might think of temperature as existing on a scale that is actually a loop, not linear. Positive temperatures make up one part of the loop, while negative temperatures make up the other part. When temperatures go either below zero or above infinity on the positive region of this scale, they end up in negative territory. [What's That? Your Basic Physics Questions Answered]

'The temperature scale simply does not end at infinity, but jumps to negative values instead.'

- Ulrich Schneider, a physicist at the University of Munich in Germany

With positive temperatures, atoms more likely occupy low-energy states than high-energy states, a pattern known as Boltzmann distribution in physics. When an object is heated, its atoms can reach higher energy levels.

At absolute zero, atoms would occupy the lowest energy state. At an infinite temperature, atoms would occupy all energy states. Negative temperatures then are the opposite of positive temperatures — atoms more likely occupy high-energy states than low-energy states.

"The inverted Boltzmann distribution is the hallmark of negative absolute temperature, and this is what we have achieved," said researcher Ulrich Schneider, a physicist at the University of Munich in Germany. "Yet the gas is not colder than zero kelvin, but hotter. It is even hotter than at any positive temperature — the temperature scale simply does not end at infinity, but jumps to negative values instead."

As one might expect, objects with negative temperatures behave in very odd ways. For instance, energy typically flows from objects with a higher positive temperature to ones with a lower positive temperature — that is, hotter objects heat up cooler objects, and colder objects cool down hotter ones, until they reach a common temperature. However, energy will always flow from objects with negative temperature to ones with positive temperatures. In this sense, objects with negative temperatures are always hotter than ones with positive temperatures.

Another odd consequence of negative temperatures has to do with entropy, which is a measure of how disorderly a system is. When objects with positive temperature release energy, they increase the entropy of things around them, making them behave more chaotically. However, when objects with negative temperatures release energy, they can actually absorb entropy.

Negative temperatures would be thought impossible, since there is typically no upper bound for how much energy atoms can have, as far as theory currently suggests. (There is a limit to what speed they can travel — according to Einstein's theory of relativity, nothing can accelerate to speeds faster than light.)

Wacky physics experiment

To generate negative temperatures, scientists created a system where atoms do have a limit to how much energy they can possess. They first cooled about 100,000 atoms to a positive temperature of a few nanokelvin, or billionth of a kelvin. They cooled the atoms within a vacuum chamber, which isolated them from any environmental influence that could potentially heat them up accidentally. They also used a web of laser beams and magnetic fields to very precisely control how these atoms behaved, helping to push them into a new temperature realm. [Twisted Physics: 7 Mind-Blowing Findings]

"The temperatures we achieved are negative nanokelvin," Schneider told LiveScience.

Temperature depends on how much atoms move — how much kinetic energy they have. The web of laser beams created a perfectly ordered array of millions of bright spots of light, and in this "optical lattice," atoms could still move, but their kinetic energy was limited.

Temperature also depends on how much potential energy atoms have, and how much energy lies in the interactions between the atoms. The researchers used the optical lattice to limit how much potential energy the atoms had, and they used magnetic fields to very finely control the interactions between atoms, making them either attractive or repulsive.

Temperature is linked with pressure — the hotter something is, the more it expands outward, and the colder something is, the more it contracts inward. To make sure this gas had a negative temperature, the researchers had to give it a negative pressure as well, tinkering with the interactions between atoms until they attracted each other more than they repelled each other.

"We have created the first negative absolute temperature state for moving particles," said researcher Simon Braun at the University of Munich in Germany.

New kinds of engines

Negative temperatures could be used to create heat engines — engines that convert heat energy to mechanical work, such as combustion engines — that are more than 100-percent efficient, something seemingly impossible. Such engines would essentially not only absorb energy from hotter substances, but also colder ones. As such, the work the engine performed could be larger than the energy taken from the hotter substance alone.

Negative temperatures might also help shed light on one of the greatest mysteries in science. Scientists had expected the gravitational pull of matter to slow down the universe's expansion after the Big Bang, eventually bringing it to a dead stop or even reversing it for a "Big Crunch." However, the universe's expansion is apparently speeding up, accelerated growth that cosmologists suggest may be due to dark energy, an as-yet-unknown substance that could make up more than 70 percent of the cosmos.

In much the same way, the negative pressure of the cold gas the researchers created should make it collapse. However, its negative temperature keeps it from doing so. As such, negative temperatures might have interesting parallels with dark energy that may help scientists understand this enigma.

Negative temperatures could also shed light on exotic states of matter, generating systems that normally might not be stable without them. "A better understanding of temperature could lead to new things we haven't even thought of yet," Schneider said. "When you study the basics very thoroughly, you never know where it may end."

The scientists detailed their findings in the Jan. 4 issue of the journal Science.

Read more: Science gets colder than absolute zero | Fox News

[Ernst]

Temperature is derived from moleculair movement. When there is no more movement it can not move slower. That is what 0 K means. A negative temperature is therefor by definition impossible. (period)

Everyone always gets older. There is not one person who gets younger over time. It is a similar definition; as time passes people get older.
But....
We read in the newspapers: "car owners get younger every year", and we know what it means: people buy cars at a younger age and/or stop driving at a younger age.
So the average age of the group of car owners goes down, while every person in this group only gets older.

It is a mathematical construct and it is fun of coarse that it can be shown in experiments, but it has absolutely no practical meaning or implications. Suppose that it did, then we would have a source of tremendous energy:

At negative temperatures matter shows a negative viscosity, meaning that an object passing through this matter is not slowed down (friction) but in stead it is accelerated.
This means it gains energy from a place where there is less than zero....
Now that would be really great, wouldn't it?

It is a mathematical construct nothing more....

Ernst.

[Farmhand]

I agree Ernst, 100% with you. It makes one wonder who is paying these people
and what is their actual value. If it's public or shareholder money paying for that,
they ought to ask for their money back. Or just stop paying them.

The theory seems delusional.
It doesn't make any sense, not common sense nor does it seem logically correct.

All I got to say after that is, WoW, OMG, WT....... ?

Cheers

[PhysicsProf]

Interesting reaction to the experimental data published in one of the premier journals of science. This is not mere conjecture/theory -- but experimental evidence.

But one has to come to grips with ENTROPY, and with new experimental data to appreciate this advancement in our understanding.

Perhaps this explanation from the journal New Scientist will help:

Cloud of atoms goes beyond absolute zero

19:00 03 January 2013 by Jacob Aron

Nothing is colder than absolute zero, so it seems nonsensical to talk about negative temperature – but now there is a substance that must have just that. The revelation could shake up our ideas about temperature and help us understand strange entities such as dark energy, as well as the interactions of subatomic particles.

Although we're used to talking about negative temperatures, such as −10°C, all temperatures on an ordinary thermometer are actually positive when measured in kelvin, the scientific temperature scale that starts at absolute zero (−273.15°C).

On the kelvin scale, temperature is determined by the kinetic energy of particles, so a gas of slow particles is colder than a gas of fast-moving ones. Absolute zero corresponds to the point at which particles stop moving completely, which is why nothing can be colder.

That does not tell the whole story, however. Temperature also depends on the way in which the particle energies are distributed within the gas, which determines their entropy, or disorder.
Energy landscape

Above absolute zero, adding more energy corresponds to an increase in entropy. Picture a hill next to a valley (see image) with the height of the landscape corresponding to the energy of a particle – and the chance of finding a particle at a certain height representing entropy. At absolute zero, particles are motionless and all have no energy so are all at the bottom of the valley, giving a minimum entropy.

As the gas heats up, the average energy of the particles increases, with some gaining lots of extra energy but most just a small amount. Spread along the side of the hill, now the particles have different energies, so entropy is higher.

According to temperature's entropic definition, the highest positive temperature possible corresponds to the most disordered state of the system. This would be an equal number of particles at every point on the landscape. Increase the energy any further and you'd start to lower the entropy again, because the particles wouldn't be evenly spread. As a result, this point represents the end of the positive temperature scale.

In principle, though, it should be possible to keep heating the particles up, while driving their entropy down. Because this breaks the energy-entropy correlation, it marks the start of the negative temperature scale, where the distribution of energies is reversed – instead of most particles having a low energy and a few having a high, most have a high energy and just a few have a low energy. The end of this negative scale is reached when all particles are at the top of the energy hill.

The resulting thermometer is mind-bending with a scale that starts at zero, ramps up to plus infinity, then jumps to minus infinity before increasing through the negative numbers until it reaches negative absolute zero, which corresponds to all particles sitting at the top of the energy hill.
Cold atoms

"The temperature scale as we know it starts at zero and goes up to infinity, but it doesn't stop there," says Ulrich Schneider of the Ludwig Maximilian University of Munich in Germany.

To enter the negative realm, Schneider and his colleagues began by cooling atoms to a fraction above absolute zero and placing them in a vacuum. They then used lasers to place the atoms along the curve of an energy valley with the majority of the atoms in lower energy states. The atoms were also made to repel each other to ensure they remained fixed in place.

Schneider's team then turned this positive temperature system negative by doing two things. They made the atoms attract and adjusted the lasers to change the atoms' energy levels, making the majority of them high-energy, and so flipping the valley into an energy hill. The result was an inverse energy distribution, which is characteristic of negative temperatures.

The atoms can't lose energy and "roll down" this hill because doing so would require them to increase their kinetic energy and this is not possible because the system is in a vacuum and there is no outside energy source. "We create a system with a lot of energy, but the particles cannot redistribute their energy so they have to stay on top of the hill," says Schneider.
Dark temperature

Cold atoms are already used to simulate the interactions of some subatomic particles. The new negative temperature set-up could be used to create simulated interactions that are not possible with positive temperatures. "They are a new technical tool in the business of quantum simulations," says Schneider.

Negative temperature may also have implications for cosmology. Dark energy, thought to explain the accelerating expansion of the universe, exerts negative pressure, which suggests it might have negative temperature – Schneider is currently discussing the idea with cosmologists.

"It is amazing experimental work," says Allard Mosk of the University of Twente in the Netherlands, who originally outlined the theory behind the experiment in 2005.

Learning more about how negative temperature systems interact both with themselves and with positive temperatures might allow us to build ultra-efficient heat engines, but these are far off, he says. "I don't think this will immediately give us new devices, but it will give us a deeper understanding about what temperature really is."

Journal reference: Science, 10.1126/science.1227831

[mbrownn]

Let me get this straight, absolute zero is a temperature at which no movement will be observed in an atom.

If I understand this, sub atomic particles can move at this temperature and all atoms are made up of sub atomic particles. From this I would sat absolute zero is an arbitrary number we came up with and by definition is incorrect.

If I understand this correctly atoms and sub atomic particles are made up of energy grouped together so any subatomic particle or quantum of energy would be measured as a negative on our kelvin scale

Ok I have come up with my understanding of this as I do not understand the content of the posts but with my understanding it is still a linear scale and not a loop.

Another possible solution could be pressure, if the pressure was high enough then it could prevent movement. This would not mean there is no energy in the atom just that we cannot see it. Thus if we cool and compress an atom it could go negative in terms of observed energy. But surely that would be an observational error.

Sorry if I am barking up the wrong tree

[madhatter]

this is further research in dark matter & energy. first thing to keep in mind is that most all scales science has derived have a start & stop point or a line vector, but in reality everything is circular or looped, by convention we just look at a segment of it.

this is a novel way to explore what dark energy is. it also goes to show just how little we know about the universe, our speck of a solar system within the heliosphere contains one type of environment, outside that ???? what happens to EM waves as they traverse thru dark matter? how do we gauge the universe if negative entropy exists?

The article is talking about the energy state of the system, that state is then correlated to temperature. re-distribution of the energy level is what they did in simple terms, in the new state the behavior is negative or opposite to conventional energy systems. Hydrogen, neon & helium have a reverse joule Thomson effect, all three are components of interstellar medium gas. What would be interesting would be to figure if those gasses behaved differently in that environment, and are those gasses present beyond the heliosphere? before someone comments on spectral lines and observation recall our visual observation is thru (ISM) filtered of those gasses, real sampling will be done hopefully when Voyager and Pioneer break thru the heliosphere and report back if possible.
bizzaro indeed....

[relgub]

[b]
"The scientists detailed their findings in the Jan. 4 issue of the journal Science."
...

Thanks for the article.
I cannot express how surprised I am by this article.

I don't really trust official science anymore (I don't believe in big bang, string theory, dark matter, antimatter, black holes, etc). Nevertheless I found this article rather interesting.

[zapzap]

I don't really trust official science anymore (I don't believe in big bang, string theory, dark matter, antimatter, black holes, etc). Nevertheless I found this article rather interesting.

Then you'll most likely love this video - three (I think) of those theories you mentioned are in a sense trashed. And a solution without them is experimentally demonstrated. Enjoy: The Primer Fields Part 1 - YouTube

There's a lot more, enjoy!

[mbrownn]

Thanks for the article.
I cannot express how surprised I am by this article.

I don't really trust official science anymore (I don't believe in big bang, string theory, dark matter, antimatter, black holes, etc). Nevertheless I found this article rather interesting.

I think this is very important, based upon what we know, it is hard to trust official science as there is an obvious agenda. It is also true to say that there is much misinformation and nonsense amongst the other "so called" scientific communities.

I am still trying to get my head around this one

[PhysicsProf]

I think this is very important, based upon what we know, it is hard to trust official science as there is an obvious agenda. It is also true to say that there is much misinformation and nonsense amongst the other "so called" scientific communities.

I am still trying to get my head around this one

I had an invited colloquium scheduled for Sept 5, 2012 at a large university, physics department (see attached announcement by them).

Unfortunately, that University department met and took a vote and I was not allowed to give the colloquium. BUT then I was invited to give a seminar on the SAME material (alternative energy, including free energy) at the University of Missouri -- and that talk (October 2012) was well-attended and enthusiastically received.

My point is that SOME University professors may be closed minded, but NOT ALL! And there are some influential "gate-keepers" who try to stop colloquia on topics that are not "politically correct," as evidenced. Others fall in line oftentimes (I've observed). But some professors and scientists remain doggedly open-minded and curious -- and I congratulate these!

[Michael John Nunnerley]

Interesting reaction to the experimental data published in one of the premier journals of science. This is not mere conjecture/theory -- but experimental evidence.

But one has to come to grips with ENTROPY, and with new experimental data to appreciate this advancement in our understanding.

Perhaps this explanation from the journal New Scientist will help:

Thanks for posting this Steven
Andrew sent me a film that I had not seen "not to do with this topic", which is to do with work of mine, see 3D magnetic field thread. We seem to get involved with our work so much that we do not see what others are doing in the same field.

Mike

[mbrownn]

I had an invited colloquium scheduled for Sept 5, 2012 at a large university, physics department (see attached announcement by them).

Unfortunately, that University department met and took a vote and I was not allowed to give the colloquium. BUT then I was invited to give a seminar on the SAME material (alternative energy, including free energy) at the University of Missouri -- and that talk (October 2012) was well-attended and enthusiastically received.

My point is that SOME University professors may be closed minded, but NOT ALL! And there are some influential "gate-keepers" who try to stop colloquia on topics that are not "politically correct," as evidenced. Others fall in line oftentimes (I've observed). But some professors and scientists remain doggedly open-minded and curious -- and I congratulate these!

The number of times I see science being decided by a vote is amazing. Even the peer review process suffers with this unscientific problem.

The big bang theory and the world being flat were decided this way.

Did you see this article Light hits near infinite speed in silver-coated glass - physics-math - 07 January 2013 - New Scientist I found it on one of the more reliable news aggregateors Headlines - David Icke Website I think it has similar implications to what you posted here

[PhysicsProf]

The number of times I see science being decided by a vote is amazing. Even the peer review process suffers with this unscientific problem.

The big bang theory and the world being flat were decided this way.

Did you see this article Light hits near infinite speed in silver-coated glass - physics-math - 07 January 2013 - New Scientist I found it on one of the more reliable news aggregateors Headlines - David Icke Website I think it has similar implications to what you posted here

Interesting article, M. -- thanks. From the New Scientist article you cited:

No threat to Einstein

The new material contains a nano-scale structure that guides light waves through the metal-coated glass. It is the first with a refractive index below 0.1, which means that light passes through it at almost infinite speed, says Albert Polman at the FOM Institute AMOLF in Amsterdam, the Netherlands. But the speed of light has not, technically, been broken. The wave is moving quickly, but its "group velocity" – the speed at which information is travelling – is near zero.

[Ernst]

Interesting reaction to the experimental data published in one of the premier journals of science. This is not mere conjecture/theory -- but experimental evidence.

But one has to come to grips with ENTROPY, and with new experimental data to appreciate this advancement in our understanding.

Perhaps this explanation from the journal New Scientist will help:

Interesting suggestion that I would need help.
Norman F. Ramsy predicted the possibility of negative temperatures for the first time. Later Allard Mosk worked this idea out providing the basis for the experiments now performed in Germany. I am fully aware that this is experimental proof, but that does not in any way invalidate my previous statement that this is a mathematical construct with NO PRACTICAL VALUE. It does by no means explain cosmological phenomena, as is suggested in the article.
It is exactly as I stated before: a group of objects can show behaviour that is impossible for any individual member of the group. The group of objects in this experiment is a number of potassium atoms in a Einstein-Bose state, meaning that they no longer behave as individual atoms. And it is only for this reason that the mentioned results could be obtained. Look at the complete report produced in Mόnchen, negative temperature, negative pressure, negative viscosity, I would say this amounts to negative presence of matter.
As I stated in my previous post here, negative viscosity would be a tremendous source of power. But if you were to try to implement this, you will find that this power is taken from your cooling equipment.
If you believe in the practical value of this sort of things, you should buy a car to reverse your aging process (see my previous post here).
To me, this is a pile of bovine faeces.

Ok Scotty, beam me up. No intelligent life signs down here.


Ernst.

Ps.: as for cosmological processes, just take electrical interactions in consideration and dark matter and all those imaginary phenomena will disappear, leaving a completely logical universe.

[mbrownn]

I don't really understand the principals of the article posted by Steve, maybe that is why I am a little sceptical but the article about light seems common sense to me.

In the absence of an article I can get my head round I will have to wait for a clearer explanation but my mind remains open.

On the light thing I compare it with some simpler things, Its sort of like a yacht sailing into the Wind, the speed gained on each tac is far in excess of the wind speed. What practical use it has remains to be seen.