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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?

#51

Post by csomar »

throw_m239339 wrote: post #31
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.

I find the idea that reality might be quantized fascinating, so that all information that exists could be stored in a storage medium big enough. It's also kind of interesting how causality allegedly has a speed limit and it's rather slow all things considered. Anyway, in 150 years we absolutely came a long way, we'll figure it that out eventually, but as always, figuring it out might lead even bigger questions and my…

If reality is quantized, how can you store all the information out there without creating a real simulation? (Essentially cloning the environment you want stored)

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

#52

Post by mhandley »

bsder wrote: post #10

Theoretical physics progresses via the anomalies it can't explain. The problem is that we've mostly explained everything we have easy access to. We simply don't have that many anomalies left. Theoretical physicists were both happy and disappointed that the LHC simply verified everything--theories were correct, but there weren't really any pointers to where to go next. Quantum gravity seems to be the big one, but that…

Neutrino mass is another anomaly, which is at least slightly easier to probe than quantum gravity: https://cerncourier.com/a/the-neutrino-mass-puzzle/

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

#53

Post by hackingonempty »

klipt wrote: post #24
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.

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

Yes, for all practical purposes. This is the position of physicist Sean Carroll and probably others. We may not know what is happening in the middle of a black hole, or very close to the big bang, but here on Earth we do.

"in the specific regime covering the particles and forces that make up human beings and their environments, we have good reason to think that all of the ingredients and their dynamics are understood to extremely high precision"[0]

0: https://philpapers.org/archive/CARCAT-33

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

#54

Post by jcranmer »

david-gpu wrote: post #28
throwup238 wrote: post #20

Earlier quoted context omitted.

Or why the quarks that make up protons and neutrons have fractional charges, with +1 protons mixing two +2/3 up quarks and one -1/3 down quark, and the neutral neutron is one up quark and two down quarks. And where are all the other Quarks in all of this, busy tending bar?

They have fractional charges because that is how we happen to measure charge. If our unit of charge had been set when we knew about quarks, we would have chosen those as fundamental, and the charge of the electron would instead be -3. Now, the ratios between these charges appear to be fundamental. But the presence of fractions is arbitrary.

> If our unit of charge had been set when we knew about quarks, we would have chosen those as fundamental, and the charge of the electron would instead be -3.

Actually, I doubt it. Because of their color charge, quarks can never be found in an unbound state but instead in various kinds of hadrons. The ways that quarks combine cause all hadrons to end up with an integer charge, with the ⅔ and -⅓ charges on various quarks merely being ways to make them come out to resulting integer charges.

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

#55

Post by elzbardico »

aatd86 wrote: post #12

Isn't it the mathematics that is lagging? Amplituhedron? Higher dimensional models? Fun fact: I got to read the thesis of one my uncles who was a young professor back in the 90's. Right when they were discovering bosons. They were already modelling them as tensors back then. And probably multilinear transformations. Now that I am grown I can understand a little more, I was about 10 years old back then. I had no idea…

Tensors are pretty old in physics; they are a central concept in Einstein's General Relativity.

You can find tensors even in some niche stuff in macroeconomics.

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

#56

Post by nancyminusone »

idiotsecant wrote: post #43
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?

Absolutely not. Newtonian physics was 'good enough' until we disproved it. Imagine where we would be if all we had was Newtonian physics.

You would still make it to the moon (so I've heard). Maybe you wouldn't have GPS systems?

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

#57

Post by Paracompact »

cozzyd wrote: post #38
Paracompact wrote: post #33

Earlier quoted context omitted.

Sure, but in that regard dark matter is even more unsatisfying than (contemporary) epicycles, because not only does it add extra complexity, it doesn't even characterize the source of that complexity beyond its gravitational effects.

Even better, there are the "nightmare" scenarios where dark matter can only interact gravitationally with Standard Model particles.

Personally—and this is where I expect to lose the materialists that I imagine predominate HN—I think we are already in a nightmare scenario with regard to another area: the science of consciousness.

The following seem likely to me: (1) Consciousness exists, and is not an illusion that doesn't need explaining (a la Daniel Dennett), nor does it drop out of some magical part of physical theory we've somehow overlooked until now; (2) Mind-matter interactions do not exist, that is, purely physical phenomena can be perfectly explained by appeals to purely physical theories.

Such are the stakes of "naturalistic dualist" thinkers like David Chalmers. But if this is the case, it implies that the physics of matter and the physics of consciousness are orthogonal to each other. Much like it would be a nightmare to stipulate that dark matter is a purely gravitational interaction and that's that, it would be a nightmare to stipulate that consciousness and qualia arise noninteractionally from certain physical processes just because. And if there is at least one materially noninteracting orthogonal component to our universe, what if there are more that we can't even perceive?

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

#58

Post by mikkupikku »

idiotsecant wrote: post #43
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?

Absolutely not. Newtonian physics was 'good enough' until we disproved it. Imagine where we would be if all we had was Newtonian physics.

Newtonian physics is good enough for almost everything that humans do. It's not good for predicting the shit we see in telescopes, and apparently it's not good for GPS, although honestly I think without general relativity, GPS would still get made but there'd be a fudge factor that people just shrug about.

For just about anything else, Newton has us covered.

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

#59

Post by throwup238 »

david-gpu wrote: post #28
throwup238 wrote: post #20

Earlier quoted context omitted.

Or why the quarks that make up protons and neutrons have fractional charges, with +1 protons mixing two +2/3 up quarks and one -1/3 down quark, and the neutral neutron is one up quark and two down quarks. And where are all the other Quarks in all of this, busy tending bar?

They have fractional charges because that is how we happen to measure charge. If our unit of charge had been set when we knew about quarks, we would have chosen those as fundamental, and the charge of the electron would instead be -3. Now, the ratios between these charges appear to be fundamental. But the presence of fractions is arbitrary.

Isn’t charge quantized? Observable isolated charges are quantized in units of e. You can call it -3 and +3 but that just changes the relative value for the quanta. The interesting question is still why the positive and neutral particles are nonelementary particles made up of quarks with a fraction of e, the math made possible only by including negatively charged ones (and yet electrons are elementary particles).

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

#60

Post by ecshafer »

aatd86 wrote: post #12

Isn't it the mathematics that is lagging? Amplituhedron? Higher dimensional models? Fun fact: I got to read the thesis of one my uncles who was a young professor back in the 90's. Right when they were discovering bosons. They were already modelling them as tensors back then. And probably multilinear transformations. Now that I am grown I can understand a little more, I was about 10 years old back then. I had no idea…

Tensors are like 200 years old in mathematics. Gauss talked about Tensors.
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