Can GW detectors detect scalar and vector radiation modes?

[PAllen]

Literally running out the door, but came upon this. It seems to be a really interesting avenue to test GR vs. other gravity theories using hoped for GW detectors.

http://arxiv.org/abs/1204.2585

 

[Nabeshin]

Literally running out the door, but came upon this. It seems to be a really interesting avenue to test GR vs. other gravity theories using hoped for GW detectors.

http://arxiv.org/abs/1204.2585

That's really interesting! This is essentially a more in depth theoretical analysis of a project I worked this past summer (unfortunately, not published). The prospect is certainly tantalizing, but realistically I am dubious. I've found that the response to scalar radiation modes in a LIGO network is down by roughly a factor of ten as compared to the tensor modes of radiation. As the paper notes, we have some constraints on how strong this scalar radiation can be from the Hulse-Taylor system. So it seems unlikely that if there were a scalar component to radiation that we would be able to detect it with the advanced-LIGO generation of detectors. As far as vector radiation is concerned, the LIGO detectors are generally much more responsive to this (comparable to tensor radiation, actually).

Since scalar modes are present in your run of the mill Brans-Dicke theory, they are the ones I understand the best. I'm not sure entirely how vector radiation is produced, and haven't looked in detail at possible sources for this, so I can't say much about its detection.