Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Is particle physics dead, dying, or just hard?

quantamagazine.org

Post reply on HN
Print view View original

211–220 of 408 posts

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

#211

Post by squeefers »

libraryofbabel wrote: post #40
rjh29 wrote: post #22

Earlier quoted context omitted.

One argument (while unsatisfying) is there are trillions of possible configurations, but ours is the one that happened to work which is why we're here to observe it. Changing any of them even a little bit would result in an empty universe.

There’s a name for that: the Anthropic principle. And it is deeply unsatisfying as an explanation. And does it even apply here? If the charge on the electron differed from the charge on the proton at just the 12th decimal place, would that actually prevent complex life from forming. Citation needed for that one. I agree with OP. The unexplained symmetry points to a deeper level.

> There’s a name for that: the Anthropic principle. And it is deeply unsatisfying as an explanation.

i feel the same about many worlds

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

#212

Post by TheOtherHobbes »

Paracompact wrote: post #57
cozzyd wrote: post #38

Earlier quoted context omitted.

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 u…

Yes, but it doesn't even need mysticism or duality.

There's a more straightforward problem, which is that all of science is limited by our ability to generate and test mental models, and there's been no research into the accuracy and reliability of our modelling processes.

Everything gets filtered through human consciousness - math, experiment, all of it. And our definition of "objective" is literally just "we cross-check with other educated humans and the most reliable and consistent experience wins, for now."

How likely is it that human consciousness is the most perfect of all possible lenses, doesn't introduce distortions, and has no limits, questionable habits, or blind spots?

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

#213

Post by T-A »

TheOtherHobbes wrote: post #208
T-A wrote: post #135

Earlier quoted context omitted.

> the standard model neutrinos can't participate in the Higgs mechanism due to always being left-handed This again? It's only true if you insist on sticking with the original form of Weinberg's "model of leptons" from 1967 [1], which was written when massless neutrinos were consistent with available experimental data. Adding quark-style (i.e. Dirac) neutrino mass terms to the Standard Model is a trivial exercise. If…

It's trivial to add a matrix to account for neutrino masses, but that doesn't explain their origin. That is not a trivial problem at all. It certainly has not been solved, and it's possible experiments will say "Both the current ideas are wrong."

> It's trivial to add a matrix to account for neutrino masses

The matrix you are thinking of is presumably the PMNS matrix [1]. It's equivalent to the CKM matrix for quarks [2]. The purpose of both is to parametrize the mismatch between flavor [3] and mass eigenstates, not "to account for neutrino masses" or "explain their origin".

As far as the standard model is concerned, neutrino masses and quark masses all originate from Yukawa couplings [4] with the Higgs field. Adding such terms to Weinberg's original model of leptons is very much a trivial exercise, and was done already well before there was solid evidence for non-zero neutrino masses.

> it's possible experiments will say "Both the current ideas are wrong."

Assuming that by "Both current ideas" you mean Dirac vs Majorana mass, those are the only available relativistic invariants. For both to be wrong, special relativity would have to be wrong. Hopefully I don't need to explain how extraordinarily unlikely that is.

[1] https://en.wikipedia.org/wiki/Pontecorvo%E2%80%93Maki%E2%80%...

[2] https://en.wikipedia.org/wiki/Cabibbo%E2%80%93Kobayashi%E2%8...

[3] https://en.wikipedia.org/wiki/Flavour_(particle_physics)

[4] https://en.wikipedia.org/wiki/Yukawa_coupling

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

#214

Post by BrandoElFollito »

GMoromisato wrote: post #11

The use of "AI" in particle physics is not new. In 1999 they were using neural nets to compute various results. Here's one from Measurement of the top quark pair production cross section in p¯p collisions using multijet final states [ https://repository.ias.ac.in/36977/1/36977.pdf ] "The analysis has been optimized using neural networks to achieve the smallest expected fractional uncertainty on the t¯t production cro…

I did my PhD in physics using nn back in 1997. It was not thriving yet, but was quite advanced already.

I remember I used a library (THE library) from a German university which was all the rage at that time.

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

#215

Post by jacquesm »

gary_0 wrote: post #162
jacquesm wrote: post #134

Earlier quoted context omitted.

> Nothing practical has been create based on those theories. Ever used GPS? A CD player? A laser? Semiconductors?

Einstein laid the theoretical foundations for lasers in 1917, and it took over 40 years of "impractical" scientific work before the first functioning laser was built. It took decades more for them to become a cheap, ubiquitous technological building-block. The research is still continuing, and there's no reason to assume it will stop eventually bearing fruit (for the societies that haven't decimated their scientific…

I sincerely wonder how someone that is unaware of any of this finds their way onto HN, but at the same time it is an educational opportunity. 'nothing practical' indeed...

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

#216

Post by selfmodruntime »

threethirtytwo wrote: post #102

All of science is getting harder as the easiest discoveries are all pretty much behind us. LLMs were a breakthrough I didn't expect and it's likely the last one we'll see in our lifetime.

The additional irony here is that LLMs are a tool that is likely forever damned to regurgitate knowledge of the past, with the inability to derive new information.

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

#217

Post by hippich »

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

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

#218

Post by hugh-avherald »

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.

Does targeting research towards 'more promising' fields actually produce greater economic returns?

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

#219

Post by varjag »

sigmoid10 wrote: post #204
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…

>Microchips were an incremental improvement where the individual increments yielded utility far greater than the investment. You should look up how modern EUV lithography was commercialised. This was essentially a big plasma physics puzzle. If ASML hadn't taken on a ridiculous gamble (financially on the same order of magnitude as a new collider, esp. for a single colpany) with the research, Moore's law would have die…

EUV lith would have absolutely been achieved if LHC wasn't ever built.
Post reply on HN