Negative Mass: Can it Exist?

[snoopies622]

Yesterday I wrote a simple computer simulation for a spring which, when released, sends two masses flying in opposite directions, and views the event from two different reference frames. My goal was just to convince myself that relativistic mechanics is self-consistent and indeed every time I changed the parameters, both momentum and energy were conserved in both reference frames.

But without realizing it at first, the program allowed for cases where the spring sent the masses flying away so fast that the spring itself was left with negative rest mass. But even in these cases, the results were consistent - both momentum and energy were conserved in both reference frames. The spring had negative mass (and negative energy), and its momentum was negative too, meaning (I guess) it was positive but in the opposite direction from which the spring was moving.

My question is: Does this have any physical meaning? Is there a modern theory or theories in which a particle gives off more energy than it has, and is left with negative mass, negative energy, carrying negative momentum, and so on?

 

[PeterDonis]

Does this have any physical meaning?

No. The fact that the math happens to work out in the particular case you considered does not make it physically meaningful.

 

[Arkalius]

As far as I'm aware, there are no physical laws that expressly forbid the existence of negative mass-energy. But, we've never observed it, and it's properties would be pretty weird. We have no reason right now to suspect such a thing actually does or could exist, but maybe we'll be surprised in the future.

 

[PeterDonis]

As far as I'm aware, there are no physical laws that expressly forbid the existence of negative mass-energy.

This is not correct if by "negative mass-energy" you mean what the OP described:

a particle gives off more energy than it has

This is indeed forbidden by physical laws.

 

[LURCH]

https://www.bibliotecapleyades.net/ciencia/negativeenergy/negativeenergy.html

As far as I'm aware, there are no physical laws that expressly forbid the existence of negative mass-energy. But, we've never observed it, and it's properties would be pretty weird. We have no reason right now to suspect such a thing actually does or could exist, but maybe we'll be surprised in the future.

Actually, I recall reading an article in Scientific American many years ago that was about negative energy, and I believe it included a reference to actual observations. I don’t know if it’s at all related to the results from the OP, but I will try to find the article again, and post a link, if it doesn’t present any copyright infringement. Properties I recall include the claims that negative energy would have negative mass, be gravitationally repulsive, and could only be present in a system containing a greater quantity of positive energy. The example I recall was taking an em wave with a trough value close to zero, and then compressing the wave so that the peek would be higher, and the trough would pass below zero.

The article spoke about warp drive and worm holes and all manner of fanciful whimsy.

EDIT TO ADD: Was able to find the link (that article was from 2000!), but couldn’t get it to add on to the end of the post. So, that’s it up at the top.

 

[PeterDonis]

I recall reading an article in Scientific American many years ago that was about negative energy

"Negative energy" is a very misleading description of what that article is talking about. A better description would be "stress-energy that violates the weak energy condition". And it still meets the condition I described in post #4: you can't get something to give off more energy than it has. So it does not qualify as "negative energy" by the definition the OP is using.

Also, Scientific American, despite its name, is not a scientific journal; articles in it are pop science articles for lay people. So they aren't really good sources for PF discussion.