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As a practicing physicist in quantum information, I can say (1) "New physics" is jargon understood by experts to mean new fundamental physics, i.e., new laws/f

As a practicing physicist in quantum information, I can say (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 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.

hpcjoe 6y ago
The Majorana fermion was just observed and reported this past year. Fundamental physics. Foundational physics. 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.
- jessriedel 6y ago
  Quasiparticles aren't changes to the theoretical foundations. They can be derived from the existing foundations. You might as well argue that new classes of molecules synthesized by chemists are new physics.
- ncmncm 6y ago
  Recent results have often depended on observations of light flashes in large bodies of water or ice. These have sometimes involved an accelerator, but present accelerators suffice. 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.
  - jessriedel 6y ago
    Neutrino experiments are a good example! A mistake on my part. I think you're right that the CKM parameters have been bounded more tightly with non-accelerator based neutrino experiments. (Of course, that's still HEP, and it still gets plenty of funding, so it doesn't detract from my point.) 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.
m463 6y ago
Not sure myself, but I wonder how much of the progress breaks down into theoretical vs experimental physics, and what types of experimental physics have paid off. Also, are there other forms of experimental physics that don't have much coverage and could shine the light in other directions?
- jessriedel 6y ago
  The rate at which new experimental input to fundamental physics is generated has slowed almost to a halt. How much you can trust theory in the absence of experimental confirmation is debated.
  - ncmncm 6y ago
    Not true. The LHC kills theories at the same rate as ever. What has fallen off is hypotheses that survive testing.
    - jessriedel 6y ago
      The only sensible way to define experimental guidance is by plausibility of the theories being falsified. (Otherwise, I rule out lots of theories every day on my walk to work because I don't witness the heretofore laws of physics melting down.) Post-Higgs and post-natural-SUSY, there are no theories that have much a priori credence. And just getting to Higgs and no-natural-SUSY, compared to the previous accelerator, took multiple decades. 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.
gaze 6y ago
Eh I disagree. I've never understood "new physics" to mean new fundamental physics. Anderson localization was "new physics." I mean, is discovering new Hadrons "new physics?" They're "just" new combinations of quarks. In that sense it's "just" quark chemistry! I think it's especially absurd since condmat systems can be interesting toy models for high energy systems. 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.
- jessriedel 6y ago
  Happy to agree that terminology may vary; for the purposes of my argument, I only need that a large fraction of physicists do use the term this way, and that that sense is meaningful and important. > 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.)

hpcjoe 6y ago

The Majorana fermion was just observed and reported this past year. Fundamental physics. Foundational physics. 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.

jessriedel 6y ago
Quasiparticles aren't changes to the theoretical foundations. They can be derived from the existing foundations. You might as well argue that new classes of molecules synthesized by chemists are new physics.
ncmncm 6y ago
Recent results have often depended on observations of light flashes in large bodies of water or ice. These have sometimes involved an accelerator, but present accelerators suffice. 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.
- jessriedel 6y ago
  Neutrino experiments are a good example! A mistake on my part. I think you're right that the CKM parameters have been bounded more tightly with non-accelerator based neutrino experiments. (Of course, that's still HEP, and it still gets plenty of funding, so it doesn't detract from my point.) 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.

m463 6y ago

Not sure myself, but I wonder how much of the progress breaks down into theoretical vs experimental physics, and what types of experimental physics have paid off. Also, are there other forms of experimental physics that don't have much coverage and could shine the light in other directions?

jessriedel 6y ago
The rate at which new experimental input to fundamental physics is generated has slowed almost to a halt. How much you can trust theory in the absence of experimental confirmation is debated.
- ncmncm 6y ago
  Not true. The LHC kills theories at the same rate as ever. What has fallen off is hypotheses that survive testing.
  - jessriedel 6y ago
    The only sensible way to define experimental guidance is by plausibility of the theories being falsified. (Otherwise, I rule out lots of theories every day on my walk to work because I don't witness the heretofore laws of physics melting down.) Post-Higgs and post-natural-SUSY, there are no theories that have much a priori credence. And just getting to Higgs and no-natural-SUSY, compared to the previous accelerator, took multiple decades. 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.

gaze 6y ago

Eh I disagree. I've never understood "new physics" to mean new fundamental physics. Anderson localization was "new physics." I mean, is discovering new Hadrons "new physics?" They're "just" new combinations of quarks. In that sense it's "just" quark chemistry! I think it's especially absurd since condmat systems can be interesting toy models for high energy systems. 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.

jessriedel 6y ago
Happy to agree that terminology may vary; for the purposes of my argument, I only need that a large fraction of physicists do use the term this way, and that that sense is meaningful and important. > 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.)