B Gravitational force between matter and antimatter

[Delta2]

What is the current scientific consensus on the gravitational force between matter and antimatter. Is it repulsive, attractive or zero?

 

[anuttarasammyak]

Antiparticle of photon is itself and photons attract.

 

[Vanadium 50]

It is a prediction of GR than it is attractive. If it were not (and indeed, not the same as for matter) it violates conservation of energy.

 

[Dale]

Yes, it is clearly predicted to be attractive, but this has not been experimentally tested yet.

 

[hmmm27]

Yes, it is clearly predicted to be attractive, but this has not been experimentally tested yet.

But, we've made antimatter... didn't anybody notice if the stuff tended to fall down, or up ?

 

[Dale]

But, we've made antimatter... didn't anybody notice if the stuff tended to fall down, or up ?

No. The antimatter that we have made is charged and it is hard to get a region where the EM field is so small that you can see which way it falls under just gravity.

 

[Gaussian97]

No. The antimatter that we have made is charged and it is hard to get a region where the EM field is so small that you can see which way it falls under just gravity.

Actually, we have made neutral antimatter, but I think that their gravitational properties haven't been studied yet.

 

[strangerep]

If one believes the press releases, various experiments might be getting close to measuring the gravitational properties of antimatter (compared to matter) at good accuracy. Check out the following article:

AEgIs -- Cern Courier Feb 2021