Physics is unreasonably good at creating new math • Hacker News Board

Re: Physics is unreasonably good at creating new math

#131

Post by zachf » Wed, Sep 04, 2024, 11:25 PM UTC

naasking wrote: post #128

zachf wrote: post #122

Earlier quoted context omitted.

There are in fact exceptionally strong incentives to discover alternatives to quantum gravity which could be tested in experiments. These are the same incentives that always drive the scientific process, and new theories cost next to zero to produce. The reason string theory is popular is not because string theorists somehow prevent funding of other directions. It is because string theory has given us tools like AdS/…

Oh Ads, you mean that space that emphatically does NOT describe our universe? Ads/CFT is overblown. It's just an interesting mathematical result that hasn't borne much meaningful fruit for actual physics. I'm sorry, but string theorists absolutely do prevent funding other research because funding is finite, grad students have to research something their advisors think is worthy, and their advisors have their heads fu…

No, this is a shallow understanding of AdS/CFT. If you want to study quantum gravity when it is weakly coupled to matter, you can use AdS/CFT regardless of whether the background space is asymptotically AdS by embedding a brane near the boundary and working in a perturbative expansion. If you want to study the physics of quantum de Sitter space with a field theory dual, you can study any of the recent work on TTbar deformations. And anyway, surely you aren’t arguing that conformal field theories are irrelevant for physics? Because that would obviously be an untenable position, and the whole point is that quantum gravity AdS (basically) is CFT (it’s an equality! It goes both ways), just in different variables. You can actually study non-gravitational physics with it, using a gravitational language. That’s awesome stuff! Please don’t dismiss this fascinating field too quickly.

By the way, I know Oppenheim personally. He gets funding from string grants. Nobody is angry about that. Anybody can do this. I don’t think his theory is going to pass any experimental validation (it requires a really severe violation of a physical principle we have tested over and over) but the entire community has always supported and listened. He gives talks at major universities. He’s not an outcast or renegade or something.

Re: Physics is unreasonably good at creating new math

#132

Post by mettamage » Wed, Sep 04, 2024, 11:39 PM UTC

jjgreen wrote: post #127

A physicist, walking home at night, spots a mathematician colleague under a street lamp staring at the ground, "something wrong?" he asks; "I've dropped my keys" he replies, "whereabouts?" asks the physicist, keen to help. "Over there" says the mathematician pointing; "So why don't you look over there?" retorts the physicist, "the light is better here" says the mathematician. Disclosure, I'm a mathematician.

I don’t get it.

Disclosure: I’m a software developer

Re: Physics is unreasonably good at creating new math

#133

Post by Ankaios » Wed, Sep 04, 2024, 11:57 PM UTC

mettamage wrote: post #132

jjgreen wrote: post #127

A physicist, walking home at night, spots a mathematician colleague under a street lamp staring at the ground, "something wrong?" he asks; "I've dropped my keys" he replies, "whereabouts?" asks the physicist, keen to help. "Over there" says the mathematician pointing; "So why don't you look over there?" retorts the physicist, "the light is better here" says the mathematician. Disclosure, I'm a mathematician.

I don’t get it. Disclosure: I’m a software developer

Non-software-developer humans often use things called "lamps" to illuminate spaces at night. Unfortunately, illumination inhibits effective nighttime coding.

Re: Physics is unreasonably good at creating new math

#134

Post by RhysU » Thu, Sep 05, 2024, 12:03 AM UTC

bee_rider wrote: post #31

tines wrote: post #7

Earlier quoted context omitted.

> it wasn't made during the nineteenth century That's because people were totally focused on physics, and math was just a useful tool sometimes. Doing physics was the true goal and observation the final arbiter of truth. Nowadays, that distinction is blurred but for the opposite reason; people think that anything conceived by sound math must be true, and observation has taken a back seat.

This was the result of Philosophers ultimately winning, despite the fact that they are so annoyingly pedantic that we pretend not to care about their work, and also, by ignoring them we can invent iPhones which are really neat. You can’t prove anything by observation. You can gather evidence through repeat experiment and become reasonably confident as your theory continues to not be incompatible with the observed uni…

> You can’t prove anything by observation.

Nice observation.

Epistemology is a harsh mistress.

Re: Physics is unreasonably good at creating new math

#135

Post by sameoldtune » Thu, Sep 05, 2024, 12:04 AM UTC

mettamage wrote: post #132

jjgreen wrote: post #127

A physicist, walking home at night, spots a mathematician colleague under a street lamp staring at the ground, "something wrong?" he asks; "I've dropped my keys" he replies, "whereabouts?" asks the physicist, keen to help. "Over there" says the mathematician pointing; "So why don't you look over there?" retorts the physicist, "the light is better here" says the mathematician. Disclosure, I'm a mathematician.

I don’t get it. Disclosure: I’m a software developer

Mathematicians like to develop new math right at the boundary of what is known. Physicists don’t have that luxury because they have to describe/model/build/etc things that correlate to what is actually going on in the world.

The mathematician of this joke would scan the edge of the light, finding nothing. Then he would keep lighting little lanterns at the perimeter to make the lighted area larger until finally his keys were within sight.

The physicist in this joke would presumably root around in the dark where she thinks her keys actually were. Upon finding them through brute force and luck, she might think “wow maybe one day this place will be illuminated so I can tell wtf I just did”

Re: Physics is unreasonably good at creating new math

#136

Post by leptons » Thu, Sep 05, 2024, 12:18 AM UTC

sameoldtune wrote: post #135

mettamage wrote: post #132

Earlier quoted context omitted.

I don’t get it. Disclosure: I’m a software developer

Mathematicians like to develop new math right at the boundary of what is known. Physicists don’t have that luxury because they have to describe/model/build/etc things that correlate to what is actually going on in the world. The mathematician of this joke would scan the edge of the light, finding nothing. Then he would keep lighting little lanterns at the perimeter to make the lighted area larger until finally his ke…

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Re: Physics is unreasonably good at creating new math

#137

Post by ndsipa_pomu » Thu, Sep 05, 2024, 12:25 AM UTC

crazydoggers wrote: post #17

I’m not sure how it could be otherwise. On some level mathematics is a description of reality that we can use to compute things in reality. For example, pi is the ratio of a circle’s circumference to its diameter. It’s just what a circle is in two dimensions. The value of pi isn’t any more mysterious or connected to physics than the existence of this thing called a circle. If you have some other Euclidean shapes you’…

Not sure that I agree as does a mathematical circle actually exist? We can produce things that approach the concept of a circle and similarly, we can measure circumference and diameter to a level of precision to approach the value of pi, but we never have a perfect circle or the exact value of pi.

I tend towards maths being distinct from physics as some areas of maths deal with concepts that can only have a passing resemblance to reality - the Banach-Tarski paradox is an example. (Similarly, pretty much any treatment of infinities ends up to have little relation to reality such as with Hilbert's Hotel).

Re: Physics is unreasonably good at creating new math

#138

Post by Ygg2 » Thu, Sep 05, 2024, 12:43 AM UTC

mettamage wrote: post #132

jjgreen wrote: post #127

A physicist, walking home at night, spots a mathematician colleague under a street lamp staring at the ground, "something wrong?" he asks; "I've dropped my keys" he replies, "whereabouts?" asks the physicist, keen to help. "Over there" says the mathematician pointing; "So why don't you look over there?" retorts the physicist, "the light is better here" says the mathematician. Disclosure, I'm a mathematician.

I don’t get it. Disclosure: I’m a software developer

The idea is that often a breakthrough in mathematics isn't achieved by tackling a problem directly, but converting it to a simpler problem, then solving that one.

Disclosure: I'm a software developer.

Re: Physics is unreasonably good at creating new math

#139

Post by tijtij » Thu, Sep 05, 2024, 12:48 AM UTC

jjgreen wrote: post #127

A physicist, walking home at night, spots a mathematician colleague under a street lamp staring at the ground, "something wrong?" he asks; "I've dropped my keys" he replies, "whereabouts?" asks the physicist, keen to help. "Over there" says the mathematician pointing; "So why don't you look over there?" retorts the physicist, "the light is better here" says the mathematician. Disclosure, I'm a mathematician.

Funny joke. Reminded me of this xkcd comic but with the roles reversed.

https://xkcd.com/435

Re: Physics is unreasonably good at creating new math

#140

Post by Hasu » Thu, Sep 05, 2024, 1:05 AM UTC

leptons wrote: post #136

sameoldtune wrote: post #135

Earlier quoted context omitted.

Mathematicians like to develop new math right at the boundary of what is known. Physicists don’t have that luxury because they have to describe/model/build/etc things that correlate to what is actually going on in the world. The mathematician of this joke would scan the edge of the light, finding nothing. Then he would keep lighting little lanterns at the perimeter to make the lighted area larger until finally his ke…

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[0] Very few practices in English writing are universal.