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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?

#261

Post by jcranmer »

adrian_b wrote: post #228
jhrmnn wrote: post #205

Earlier quoted context omitted.

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…

> 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.

Um, false? The fundamentals of chemistry are about electron orbitals (especially the valence ones) and their interactions between atoms to form molecules. All of my college chemistry courses delved somewhat into quantum mechanics, with the biggest helping being in organic chemistry. And modern computational chemistry is basically modeling the QED as applied to atoms.

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

#262

Post by orbifold »

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…

I guess we will find out in 20+ years once the next electron positron collider at CERN has been build

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

#263

Post by nobodyandproud »

bl0rg wrote: post #185
brazzy wrote: post #176

Earlier quoted context omitted.

> 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. No. These two cases are absurdly different, and you're even completely misunderstanding (or misrepresenting) the meaning of the "tens of billions of dollars" figure. Microchips were an incremental improvement where the ind…

> The latest ones cost billions and have confirmed a few things we already thought to be true. Yes, but we had hopes that it would lead to more. And had lead to more, something only known to be false in hindsight, who knows where that would have ended us up? What if it upended the standard model instead of reinforcing it? > Absolutely not. What are we supposed to do then? As humans, I mean. No one knows why we're her…

> I'm not arguing for mindlessly building bigger accelerators, and I don't think anyone is

You sure about that?

The GP whose position you’re defending wrote this:

> Let the physicists build the damn thing however they want and future society will be better off for sure.

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

#264

Post by padjo »

kdavis wrote: post #255
layer8 wrote: post #250

Earlier quoted context omitted.

That depends on what you compare it to.

Almost anything, i.e. the next generation accelerator[1] at CERN is about 15B CHF which is about 20B USD. [1] https://home.cern/science/accelerators/future-circular-colli...

So roughly half the the annual budget of ICE?

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

#265

Post by nobody9999 »

brazzy wrote: post #190
bl0rg wrote: post #185

Earlier quoted context omitted.

> The latest ones cost billions and have confirmed a few things we already thought to be true. Yes, but we had hopes that it would lead to more. And had lead to more, something only known to be false in hindsight, who knows where that would have ended us up? What if it upended the standard model instead of reinforcing it? > Absolutely not. What are we supposed to do then? As humans, I mean. No one knows why we're her…

> Yes, but we had hopes that it would lead to more. And had lead to more, something only known to be false in hindsight, who knows where that would have ended us up? What if it upended the standard model instead of reinforcing it? Sure, but it didn't. Which is knowledge that really should factor into the decision to build the next, bigger one. > What are we supposed to do then? As humans, I mean. Invest the money and…

>> Yes, but we had hopes that it would lead to more. And had lead to more, something only known to be false in hindsight, who knows where that would have ended us up? What if it upended the standard model instead of reinforcing it?

>Sure, but it didn't. Which is knowledge that really should factor into the decision to build the next, bigger one.

Not this week, no. And if, next week (or next year or next decade) we resolve some of the most significant problems in modern physics, any expenditures in those fields were a waste?

You've repeatedly bashed particle physics based on your perception of a lack of progress vis-a-vis the costs, and claimed that other fields should be prioritized. Which fields? What would you hope to gain from those fields?

Is there no room for basic research that attempts to validate the bases (Standard Model, Quantum Field Theory, the marriage of the former with General Relativity, etc.) of modern physics? If not why not? Our models are definitely wrong, but they're measurably less wrong than previous models.

Should we not continue to hone/probe those models to find the cracks in the theories underpinning those models? If we don't, how will we solve these extant issues?

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

#266

Post by marcosdumay »

franktankbank wrote: post #256
empath75 wrote: post #232

Earlier quoted context omitted.

> something like a winding number (which has to be an integer). Electric charge is a kind of "defect" or "kink" in the photonic field, while color charge (quarks) are defects in the strong-force field, etc. Quark's don't have integer charge

Redefine the down quark charge as the fundamental unit and you lose nothing.

> you lose nothing

For some reason electrons have charge -3 then, that coincides with the proton charge for no good reason.

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

#267

Post by snowwrestler »

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.

In the scope of international cooperation, tens of billions of dollars is not very much money. For context, the U.S. economy generates $10 billion every ~3 hours. One private company, Google, spends $10 billion in about 2 weeks.

So look at it this way. Let’s take a bunch of the smartest people alive, train them for decades, give them a month of Google money, and they’ll spend 30 years advancing engineering to probe the very fabric of reality. And everything they learn will be shared with the rest of humanity for free.

Sounds like a pretty good deal to me.

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

#268

Post by phkahler »

tasty_freeze wrote: post #15

Here is one fact that seems, to me, pretty convincing that there is another layer underneath what we know. The charge of electrons is -1 and protons +1. It has been experimentally measured out to 12 digits or so to be the same magnitude, just opposite charge. However, there are no theories why this is -- they are simply measured and that is it. It beggars belief that these just happen to be exactly (as far as we can…

I'm convinced there are some semi-classical explanations that just haven't been figured out.

Electrons are helically moving photons: https://www.researchgate.net/publication/281322004_The_elect...

That's some interesting/wacky stuff, but there has been more research to improve those calculations - like deriving the electron charge and magnetic moment.

Personally I like the idea that a proton is somehow literally an electron and 3 up quarks (a neutron gets 2 electrons and 3 up quarks). I am not a physicist though, so I'm sure there are reasons they "know" this is not the case.

I find it fascinating that some physicists say wave functions are somehow "real" and then we've got Jacob Barandes saying you don't even need wave functions to do the computations of QM: https://www.youtube.com/watch?v=7oWip00iXbo

IMHO there is a lot of exploration to be done without particle accelerators.

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

#269

Post by phkahler »

andyferris wrote: post #114
tasty_freeze wrote: post #15

Here is one fact that seems, to me, pretty convincing that there is another layer underneath what we know. The charge of electrons is -1 and protons +1. It has been experimentally measured out to 12 digits or so to be the same magnitude, just opposite charge. However, there are no theories why this is -- they are simply measured and that is it. It beggars belief that these just happen to be exactly (as far as we can…

The hint from quantum field theory (and things like lattice gauge theory) is that charge emerges from interesting topological states/defects of the underlying field (by "interesting topological shapes" I mean - imagine a vortex in the shape of a ring/doughnut). It's kind of a topological property of a state of the photonic field, if you will - something like a winding number (which has to be an integer). Electric cha…

Have you seen this: https://www.researchgate.net/publication/281322004_The_elect...

Or any of the more recent work that references it?

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

#270

Post by skeptic_ai »

meindnoch wrote: post #108
im3w1l wrote: post #93

Earlier quoted context omitted.

I've thought about this possibility but come to reject it. If mind-matter interactions did not exist, then matter could not detect the presence of mind. And if the brain cannot detect the mind then we wouldn't be able to talk or write about the mind.

Or, the mind is in spectator mode?

From a physics point of view should be as every effect is caused by previous state. And next tick is always next tick, except quantum bacause has some randomness, but let’s assume it’s a seeded randomness.

I think every tick is predictable from previous state. Inevitable. Therefore I really like how you put it: mind is just spectating.

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