Negative Mass created; Accelerates towards you when pushed away.

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Neurotic Void Melody

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Ok, i know not many people will care much about this, but this is an interesting development nonetheless;

https://m.phys.org/news/2017-04-physicists-negative-mass.html

Washington State University physicists have created a fluid with negative mass, which is exactly what it sounds like. Push it, and unlike every physical object in the world we know, it doesn't accelerate in the direction it was pushed. It accelerates backwards.

The phenomenon is rarely created in laboratory conditions and can be used to explore some of the more challenging concepts of the cosmos, said Michael Forbes, a WSU assistant professor of physics and astronomy and an affiliate assistant professor at the University of Washington. The research appears today in the journal Physical Review Letters, where it is featured as an "Editor's Suggestion."

Hypothetically, matter can have negative mass in the same sense that an electric charge can be either negative or positive. People rarely think in these terms, and our everyday world sees only the positive aspects of Isaac Newton's Second Law of Motion, in which a force is equal to the mass of an object times its acceleration, or F=ma.In other words, if you push an object, it will accelerate in the direction you're pushing it. Mass will accelerate in the direction of the force.

"That's what most things that we're used to do," said Forbes, hinting at the bizarreness to come. "With negative mass, if you push something, it accelerates toward you."

Conditions for negative mass

He and his colleagues created the conditions for negative mass by cooling rubidium atoms to just a hair above absolute zero, creating what is known as a Bose-Einstein condensate. In this state, predicted by Satyendra Nath Bose and Albert Einstein, particles move extremely slowly and, following the principles of quantum mechanics, behave like waves. They also synchronize and move in unison as what is known as a superfluid, which flows without losing energy.

Led by Peter Engels, WSU professor of physics and astronomy, researchers on the sixth floor of Webster Hall created these conditions by using lasers to slow the particles, making them colder, and allowing hot, high energy particles to escape like steam, cooling the material further.

The lasers trapped the atoms as if they were in a bowl measuring less than a hundred microns across. At this point, the rubidium superfluid has regular mass. Breaking the bowl will allow the rubidium to rush out, expanding as the rubidium in the center pushes outward.

To create negative mass, the researchers applied a second set of lasers that kicked the atoms back and forth and changed the way they spin. Now when the rubidium rushes out fast enough, if behaves as if it has negative mass."Once you push, it accelerates backwards," said Forbes, who acted as a theorist analyzing the system. "It looks like the rubidium hits an invisible wall."

Avoiding underlying defects

The technique used by the WSU researchers avoids some of the underlying defects encountered in previous attempts to understand negative mass.

"What's a first here is the exquisite control we have over the nature of this negative mass, without any other complications" said Forbes. Their research clarifies, in terms of negative mass, similar behavior seen in other systems.This heightened control gives researchers a new tool to engineer experiments to study analogous physics in astrophysics, like neutron stars, and cosmological phenomena like black holes and dark energy, where experiments are impossible."It provides another environment to study a fundamental phenomenon that is very peculiar," Forbes said.

Link to paper, but shitty publishing control means access is pay-walled and while i do not condone giving in to this practice, it is still the best i can provide with the limitations at hand, apologies;

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.118.155301

The mysteries behind the behaviour of matter cooled to just above absolute zero strike again! But what does it mean for the future of science now? And, as a certain confused human used to ask in the past; how does it affect me? And by "me" i mean "you" because the former's mostly decided.
 

Thaluikhain

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"if behaves as if it has negative mass"

I'm leaning towards this not having negative mass in any real sense, but acting strangely. Bose-Einstein condensates are weird, that's not to say they have negative mass.
 

Neurotic Void Melody

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inu-kun said:
Shouldn't this make the matter move up due to the pull from gravity?
The scale is too miniscule and gravity too weak a force for sensitivity to be observed in that sense as far as I'm aware of.

Thaluikhain said:
"if behaves as if it has negative mass"

I'm leaning towards this not having negative mass in any real sense, but acting strangely. Bose-Einstein condensates are weird, that's not to say they have negative mass.
I noticed that, but even within those boundaries, if they can maintain such control over its' behaviour from now, the opportunities for further experimentation are quite tantalising.
 

DoPo

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This so reminds me of the voice description for the wraith suit in XCOM 2


"technically violates the laws of physics"

Anyway - that sounds very very cool. And I do mean the pun and the fact that it's fascinating. It's a really exciting development. Man, I love it when scientists do stuff like that.

Can anyone educate me on how the super cooling through lasers works?
 

Satinavian

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Bose-Einstein condensates are fun.

But "negative mass" is only a stupid buzzword for a completely unrelated behavior.

Even if you just read the abstract, "negative mass" becomes "negative effective mass". And effective mass is a term used when a complex system is modelled with a simpler system where the remaining bodies have different mass. It is usually used to get rid of some external forces in the formulas or to account for a non inertial frame of refference. It is not really a physical quantity, just a calculation trick.

It is probably still a good paper. Always nice, when you can experimentally produce results matching your Gross-Pitaevskii calculations. Usually that means the calculations are correct and your experimental setup is free of unknown influences.


P.S. :

Cooling with lasers.

Basically light can transfer momentum. If a particle moves towards a light sorce and absorbs a photon it gets slower. When it moves away, it gets faster. When it emits a photon, it gets a push in a random direction which is irrelevant.

Heat is movement. So we want particles to absorb, when they move towards a lightsource, not, when they move away. That can be achieved by using lasers as lightsource and a material which is resonant, when the light is slightly blueshifted and not resonant, when it is redshifted.

Then we need just lasters from all directions and the matter cooles down. Does obviously only work with gases in a high vacuum.
 

DoPo

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Satinavian said:
Cooling with lasers.

Basically light can transfer momentum. If a particle moves towards a light sorce and absorbs a photon it gets slower. When it moves away, it gets faster. When it emits a photon, it gets a push in a random direction which is irrelevant.

Heat is movement. So we want particles to absorb, when they move towards a lightsource, not, when they move away. That can be achieved by using lasers as lightsource and a material which is resonant, when the light is slightly blueshifted and not resonant, when it is redshifted.

Then we need just lasters from all directions and the matter cooles down. Does obviously only work with gases in a high vacuum.
Thanks! That's very neat. I'm not a physics guy but I understood that explanation. I had an assumption of how it'd work but I wanted somebody else to explain it to see if it was correct and it seems that it wasn't.
 
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Satinavian said:
Then we need just lasers from all directions and the matter cooles down. Does obviously only work with gases in a high vacuum.
Thanks for the clarification, I suspected as much but I don't have as much technical knowledge as some of the people here.

Whenever something like this is discovered or created, the first thing I think about is what are the practical applications, and can the armed forces turn it into something that can kill us all ;-)