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Is particle physics dead, dying, or just hard?

quantamagazine.org

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Re: Is particle physics dead, dying, or just hard?

#221

Post by samus »

hippich wrote: post #217
mattlangston wrote: post #71

Experimental particle physicist here. It's just hard. I measured the electron's vector coupling to the Z boson at SLAC in the late 1990s, and the answer from that measurement is: we don't know yet - and that's the point. Thirty years later, the discrepancy between my experiment and LEP's hasn't been resolved. It might be nothing. It might be the first whisper of dark matter or a new force. And the only way to find ou…

Is it hard as in: 1) we know what to do, but it is expensive 2) we don't know what to do exactly, but many more people involved can increase search speed, so just need more people 3) it is purely sequential problem, and therefore it takes a lot of time

A combination to some degree. Scientists yearn to stumble upon something hitherto unexplainable that requires a new theory or validates or definitely rules out some of the more fringe theories.

While other natural sciences often suffer from an abundance of things that "merely" need to be documented, or where simulation capability is the limit, particle physics is mostly based on a theoretical framework from the middle of the 20th century that has mostly beth explored.

Getting ahead in particle physics comprises measuring many arcane numbers to as high precision as possible until something doesn't line up with existing theories or other measurements anymore. More people could help with brainstorming and measuring things that don't require humongous particle accelerators.

Re: Is particle physics dead, dying, or just hard?

#222

Post by KolibriFly »

mattlangston wrote: post #71

Experimental particle physicist here. It's just hard. I measured the electron's vector coupling to the Z boson at SLAC in the late 1990s, and the answer from that measurement is: we don't know yet - and that's the point. Thirty years later, the discrepancy between my experiment and LEP's hasn't been resolved. It might be nothing. It might be the first whisper of dark matter or a new force. And the only way to find ou…

So, if the answer were obvious or quick, it wouldn't be worth building machines that take decades to design

Re: Is particle physics dead, dying, or just hard?

#223

Post by KolibriFly »

bananaflag wrote: post #7

It's basically the opposite situation from 150 years ago. Back then, we thought our theory was more or less complete while having experimental data which disproved it (Michelson-Morley experiment, Mercury perihelion, I am sure there are others). Right now, we know our theories are incomplete (since GR and QFT are incompatible) while having no experimental data which contradicts them.

This era might be one where we have to earn the next clue much more slowly

Re: Is particle physics dead, dying, or just hard?

#224

Post by accidentallfact »

sigmoid10 wrote: post #167
sashank_1509 wrote: post #158

Earlier quoted context omitted.

What would the cost of the “next machine” be? Is it going to be tens of billions or can we make progress with lesser money. If it is going to be tens of billions, then maybe we need to invest in engineering to reduce this cost, because it’s not sustainable to suspend thirty years, tens of billions for every incremental improvement.

This kind of slow, incremental improvement that costs tens of billions of dollars and takes decades gave us the microchips that ultimately enabled you to type this comment on your phone/computer. The return on that investment is obvious. But it is not just about making money: The entire field of radiation therapy for cancer exists and continues to improve because people figured out ways to control particle beams with…

I'm so sick of this "good guy approach". It didn't give us progress, it gave us those like Watt and Intel, highly celebrated bullshiters who stopped being relevant as soon as their IP deadlock expired.

I suppose the only solution is undeground science. Do enough progress in silence, dont disseminare the results, unless the superiority becomes so obvious that an armed resistance becomes unthinkable.

Re: Is particle physics dead, dying, or just hard?

#225

Post by XorNot »

brazzy wrote: post #193
plastic-enjoyer wrote: post #182

Earlier quoted context omitted.

> Absolutely not Engineers not being able to fathom that by building this huge-ass and complicated machines to answer questions about the fundamentals of nature, other problems are solved or new things are invented that improve and change our life will never not be funny to me

Just as funny as armchair science enthusiasts not being able to fathom that research budgets are limited and it makes sense to redirect them into other, more promising fields when a particular avenue of research is both extremely expensive and has shown diminishing returns for decades.

The more important question is, are you content with simply dismantling any progress in accelerator science at all for the next century? Because the LHCs successors won't be online till the 2050s at least. If you don't fund them now though and start the work, then no one does the work, no one studies the previous work (because there's no more grant money in it) and the next generation of accelerator engineers and physcists doesn't get trained and the knowledge and skill base withers and literally dies.

Because the trade off of no new accelerators is the definite end of accelerator science for several generations.

Re: Is particle physics dead, dying, or just hard?

#226

Post by ForgotIdAgain »

sashank_1509 wrote: post #158
mattlangston wrote: post #71

Experimental particle physicist here. It's just hard. I measured the electron's vector coupling to the Z boson at SLAC in the late 1990s, and the answer from that measurement is: we don't know yet - and that's the point. Thirty years later, the discrepancy between my experiment and LEP's hasn't been resolved. It might be nothing. It might be the first whisper of dark matter or a new force. And the only way to find ou…

What would the cost of the “next machine” be? Is it going to be tens of billions or can we make progress with lesser money. If it is going to be tens of billions, then maybe we need to invest in engineering to reduce this cost, because it’s not sustainable to suspend thirty years, tens of billions for every incremental improvement.

I think that engineering progress made while building those machines are maybe more relevant for practical technical development than the discovery they make.

Re: Is particle physics dead, dying, or just hard?

#227

Post by nephihaha »

squeefers wrote: post #202
nephihaha wrote: post #187

When the model appears to have massive problems, maybe it's time to go back and revise it.

or if youre micho kaku, just parrot it on low grade tv shows and public appearances because its easier to gain notoriety than to do science

Yes, that too LOL. He really is a grifter. But he is entertaining on TV and has that eccentric professor look about him.

Heinz Wolff used to fill a similar role on British TV.

Re: Is particle physics dead, dying, or just hard?

#228

Post by adrian_b »

jhrmnn wrote: post #205
adrian_b wrote: post #191

Earlier quoted context omitted.

The existing theories are extremely far from being good enough for practical purposes. There exists a huge number of fundamental quantities that should be calculated from the parameters of the "standard model", but we cannot compute them, we can only measure them experimentally. For instance, the masses and magnetic moments of the proton, of the neutron and of all other hadrons, the masses and magnetic moments of the…

This depends very much on what "practical purposes" are. For almost all conceivable technology, relativistic quantum mechanics for electrons and light, ie QED, is sufficient fundamental theory. This is unlike before quantum mechanics, when we basically didn't have fundamental laws for chemistry and solid-state physics.

The vast majority of useful things cannot be computed with QED from fundamental principles. You cannot compute even simple atomic energy spectra.

The fundamental laws of chemistry have not been changed much by quantum physics, they just became better understood and less mysterious. Quantum mechanics has explained various cases of unusual chemical bonds that appeared to contradict the simpler rules that were believed to be true before the development of quantum physics, but not much else has practical importance.

Solid-state physics is a much better example, because little of it existed before quantum physics.

Nevertheless, solid-state physics is also the most obvious example that the current quantum physics cannot be used to compute anything of practical value from first principles.

All solid-state physics is based on experimentally-measured parameters, which cannot be computed. All mathematical models that are used in solid-state physics are based on guesses about how the solutions could behave, e.g. by introducing various fictitious averaged potentials in equations, like the Schroedinger equation, and they are not based on computations that use primary laws, without guesses that do not have any other justification, except that when the model is completed with the experimentally-measured values for its parameters, it can make reasonably accurate predictions.

Using empirical mathematical models of semiconductor materials, e.g. for designing transistors, is perfectly fine and entire industries have been developed with such empirical models.

However, the fact that one must develop custom empirical models for every kind of application, instead of being able to derive them from what are believed to be the universal laws of quantum physics, demonstrates that these are not good enough.

We can live and progress very well with what we have, but if someone would discover a better theory or a mathematical strategy for obtaining solutions, that could be used to compute the parameters that we must now measure and which could be used to model everything that we need in a way for which there would be guarantees that the model is adequate, then that would be a great advance in physics.

Re: Is particle physics dead, dying, or just hard?

#229

Post by davrosthedalek »

adrian_b wrote: post #191
klipt wrote: post #24

Earlier quoted context omitted.

Doesn't that imply our theories are "good enough" for all practical purposes? If they're impossible to empirically disprove?

The existing theories are extremely far from being good enough for practical purposes. There exists a huge number of fundamental quantities that should be calculated from the parameters of the "standard model", but we cannot compute them, we can only measure them experimentally. For instance, the masses and magnetic moments of the proton, of the neutron and of all other hadrons, the masses and magnetic moments of the…

Lattice-QCD can, by now, actually calculate the masses of the proton, neutron from first principles pretty accurately.

This is of course a brute-force approach. We currently lack, in all fields, theory for emergent properties. And the mass of the proton definitely is such.

Re: Is particle physics dead, dying, or just hard?

#230

Post by A_D_E_P_T »

recursivecaveat wrote: post #61
klipt wrote: post #24

Earlier quoted context omitted.

Doesn't that imply our theories are "good enough" for all practical purposes? If they're impossible to empirically disprove?

Maybe? We seem to be able to characterize all the stuff we have access to. That doesn't mean we couldn't say produce new and interesting materials with new knowledge. Before we knew about nuclear fission we didn't realize that we couldn't predict that anything would happen from a big chunk of uranium or the useful applications of that. New physics might be quite subtle or specific but still useful.

All the stuff we have access to?

There isn't even a general physical theory of window glass -- i.e. of how to resolve the Kauzmann paradox and define the nature of the glass transition. Glass is one of man's oldest materials, and yet it's still not understood.

There's also, famously, no general theory for superconducting materials, so superconductors are found via alchemical trial-and-error processes. (Quite famously a couple of years ago, if you remember that circus.)

Solid-state physics has a lot of big holes.

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