[bvv]

The main problem is that the supposed violation of momentum conservation. This law is very deeply ingrained in all the current fundamental theories of physics, from the standard model to general relativity. These theories are extremely successful in describing phenomena all the way from subnuclear scales to cosmological scales, as well as nearly everything in between. This leads to two issues:

(a) If these models break down somewhere I would expect it to happen under much more extreme conditions and not with a 'table-top' experiment like this one.

(b) As far as I can see, giving up momentum conservation is not a feature that we can simply 'bolt onto' the existing models. It would require a radical rethinking of the very foundations of our current physical models.

So my personal attitude is that extraordinary claims require extraordinary evidence and this paper is not remotely convincing.

This experiment reminds me very much of the faster-than-light neutrinos. The authors of that experiment also seemed careful enough to not overstate their claims but this did not prevent a massive public interest in an ultimately debunked result. I expect the results in this paper to go the same way.

[sfifs]

> (a) If these models break down somewhere I would expect it to happen under much more extreme conditions and not with a 'table-top' experiment like this one.

To push back on this kind of thinking a bit, Einstein's breakthrough papers on Brownian motion (which served as evidence of existence of Atoms and Molecules) and the photo electric effect (which demonstrated validity of the Quantum theory of light) were very much "tabletop" effects.

While there's no denying this requires extraordinary proof, I think it's equally important for physicists to prevent themselves being biased by pre-conceived notions.

[kwhitefoot]

> were very much "tabletop" effects.

Yes but they were very well known tabletop effects. What was lacking was the theory to explain them.

[snowwrestler]

They were well-known by Einstein's time because by then they had been demonstrated many times. But someone had to have been the first to see and report the photoelectric effect.

What we need now is other physicists to test their own "Q thruster." If no one else detects a thrust, well, fine, chalk it up to weird error and move on. If other people do find a thrust, then we're into "we don't have a theory yet" territory.

[avian]

> If these models break down somewhere I would expect it to happen under much more extreme conditions and not with a 'table-top' experiment like this one.

I agree and I'm skeptical myself. But note that models just barely break in this experiment. The deviation from theory (if real) is so small that it's almost unmeasurable. The models might break in a more severe way if extreme conditions are applied in a correct way.