No accelerators needed.
Bose-Einstein condensates have been observed and used in a variety of situations.
No accelerators needed.
And I could go on.
The point is though, fundamental foundational physics is available and accessible in all the various sub-fields.
You might as well argue that new classes of molecules synthesized by chemists are new physics.
Many people think gravitational wave observations matter.
It would not be surprising if completely new, unanticipated plasma fluid phenomena turn up, when someone looks.
People are still trying to understand superconductivity, and have not needed accelerators thus far.
On the other hand, superconductivity is not a good example. It's a still-confusing phenomenon, but the vast majority of physicists believe to follows directly from the known laws of non-relativistic quantum mechanics.
But you know, whatever. The fact is that we as physicists are fighting over crumbs. We should instead be political outside our circle rather than fighting internally. The fact that our budget is orders of magnitude smaller than the defense budget is insane.
Also-also, there's plenty of tabletop fundamental experiments. Superconducting cavity based axion searches for instance.
> Also-also, there's plenty of tabletop fundamental experiments. Superconducting cavity based axion searches for instance.
Yes, sure, such experiments could find new fundamental physics. (And it should be funded!) But the Bayesian credence the overall field places on this happening is quite low, and certainly much lower than a next generation accelerator. No table-top experiments have found new fundamental physics in many decades.
(Of course, the accelerator is arguably a much worse deal given its extraordinary price.)
Also, are there other forms of experimental physics that don't have much coverage and could shine the light in other directions?
This slow rate is to be compared to vastly faster rate at which new experimental input was rolling in in the '30s, '40s, '50s, and '60s.
(1) "New physics" is jargon understood by experts to mean new fundamental physics, i.e., new laws/forces/particles at the base of our theoretical edifice. This does not mean that non-fundamental physics is necessarily less important -- see for instance the late Phillip Anderson's "More is different" [ https://science.sciencemag.org/content/177/4047/393 ] -- but the distinction is real and meaningful. The use of this phrase does not equate physics with HEP physics. The reason you might make that mistake is because...
(2) To my knowledge, every single discovery of new physics in the past half century years has been made with a particle accelerator. I am confident that a new particle accelerator is a lot more likely to discover new physics than building a quantum computer or any other experimental work in quantum information. This, I'm sure, is the consensus view, even among people who put a low credence on the chance that new physics will be found at the next accelerator, or that such an investment is worthwhile.
(3) In my opinion, the strongest argument for pursuing quantum information experiments over HEP is that a departure from quantum mechanics would be more revolutionary than merely finding another set of particles and forces with largely unexplained parameters. In that sense, you need to make the reverse argument to the one you are trying to make, i.e., that quantum information is more fundamental than HEP. But for the very same reason, discrepancies with quantum mechanics are just very, very unlikely to be found.