I have always been fascinated by the problem of quantum gravity but, well, it somehow happened "too late", after I got also very deeply into "computing" (mostly HPC, GPGPU, rendering). Does anybody know if there is a way for somebody with my background to actually help/contribute in advancing this field?
A physicist who bets that gravity can’t be quantized
211–220 of 378 posts
Re: A physicist who bets that gravity can’t be quantized
#212Earlier quoted context omitted.
Why would gravity behave different than Higgs field?
Any reason you are specifically picking the Higgs field in your question? I am asking, because this sounds a bit like you are riffing on a common misconception that the Higgs field has something to do with gravity, which is not the case. The interaction with the Higgs field is the reason some (only some) of the particles have a mass, but explaining gravity does not need to have anything to do with the Higgs field. Bu…
My understanding is that the Higgs field should be simpler than gravity because it's just a static value whereas gravity is SU(1)? At least to me it seems logical that if the Higgs is quantized, surely more complicated fields would be as well?
Re: A physicist who bets that gravity can’t be quantized
#213Earlier quoted context omitted.
> the interaction with space-time acts as some decoherence process. Well, the question is, can we use gravity in the same way that we use quantum processes, i.e., in a coherent way? If we can, e.g. using it to establish entanglement, then the theory you describe cannot hold.
Thats definitely a good question, and one that people have thought about before. I think its amazingly difficult to test it experimentally, even compared to something like directly measuring to see whether a massive object in superposition is forced to decohere faster than we expect, which is already incredibly difficult.
I was taught that choosing a QM interpretation is a matter of taste. Am I understanding correctly that we do have proposed quantum gravity experiments that can falsify various QM interpretations, it's just that they are all very hard to execute?
Re: A physicist who bets that gravity can’t be quantized
#214Earlier quoted context omitted.
These are just mathematical tools we use to make predictions. Assuming they represent objective reality and somehow prove an infinite number of universes doesn’t seem very scientific to me.
That's way too instrumentalist. The math also describes how atoms work and many other things. Modern physical understanding is based on those descriptions. Cosmology and nuclear physics would be useless without an understanding. How do the predictions work if they aren't in some way modeling the way reality is? Why does the technology based on them work? Instrumentalism gives no answers to those questions. Science is…
They work because they use human logic which has evolved to understand the universe just enough to “work” and where that logic doesn’t work we use probabilities to ensure we’re only calculating the odds and deriving from there. You can devise probabilistic systems of equations to describe stock prices and account for when you could be wrong, but this is not you describing some objective set of equations the market emanates from.
It working doesn’t mean it in anyway reflects some objective truth (if such a thing even exists.) It just breaks things down into small enough parts you can then model those parts and make predictions. This does not mean those small parts are “real” just that they are convenient ways to describe the flowing of energy for our purposes.
> atoms work and many other things
Atoms are still just a human created mathematical abstraction we use to describe and make predictions about matter. All there really is is energy and atoms are just a mathematical tool we use to study energy.
This is quite literally the oldest debate in natural science and it seems like one half of the debate just decided they’re right a few centuries ago and stopped caring about the fact that’s not something they have (or can) ever proved.
They’re tools, don’t get me wrong they are very useful ones, but the second you start pretending they’re anything else or that your interpretation of them is how reality really works you become just another religious zealot and that goes against everything science is supposed to be about.
Re: A physicist who bets that gravity can’t be quantized
#215If you believe in the Everett Interpretation, then he is wrong. The Everett Interpretation, aka Many Worlds, holds that both observer and observed are quantum mechanical systems. From this it follows that the act of observation does not produce a "collapse", but it does separate the observer into multiple observers that can't interact with each other again. So Schrödinger's cat is in a superposition of alive and dead…
In Everettian Mechanics, decoherence occurs long before the box is opened. The photons in the box interact with the cat. That entanglement with the environment which causes the branching of the wave function occurs then. The observer that opens the box is already either in a branch where the cat is asleep (to borrow from Sean Carroll) or awake. The interesting thing to come to understand is that probability doesn't a…
But the observer is in all “probabilities” no?
Re: A physicist who bets that gravity can’t be quantized
#216Earlier quoted context omitted.
I have questions about your understanding. Or maybe it is a problem with my communication. There is a planck constant. https://en.m.wikipedia.org/wiki/Planck_constant
Planck's constant is not the Planck length.
The Planck length ℓ P is defined as: ℓ P = ℏ G c 3 ≈ 1.616 255 ( 18 ) × 10 − 35 m , where is the speed of light, G is the gravitational constant, and ħ is the reduced Planck constant.
I know they’re not the same. But they obviously depend on each other, no?
Re: A physicist who bets that gravity can’t be quantized
#217does this mean there's an ultraviolet catastrophe for gravitational waves?
Re: A physicist who bets that gravity can’t be quantized
#218I have always been fascinated by the problem of quantum gravity but, well, it somehow happened "too late", after I got also very deeply into "computing" (mostly HPC, GPGPU, rendering). Does anybody know if there is a way for somebody with my background to actually help/contribute in advancing this field?
I always wonder if we could draw some parallels between an universe and a simulation.
Time -> reason why universe is expanding
Lots of quantum mechanic problems -> something that actually in theory could be simulated - but "lots of stuff is happening at the same time" (tons of fields and particles flying around, so things are "unpredictable")
Particles are not particles but manifolds
Time slows down around heavy objects like black holes - the same way servers slow down when they have this massive battle of thousands of ships in Eve online -> it is difficult to run a simulation
So the question would be, can we escape one layer up -> to the virtual machine what is simulating our reality? Same way some program can escalate privilege and see what is inside the system. What would be a good way to escalate privileges and break free from a virtual machine? And by this, I mean the theoretical machine that runs our reality?
Re: A physicist who bets that gravity can’t be quantized
#219Earlier quoted context omitted.
Why should we not just take it as a probability based abstraction for something we don’t have a true understanding of and move on? Anything else seems like weird theology to me.
1) Because physics has had an ontology, what there really is, since like Aristotle. Even if ontology changes, posing one has worked for roughly 2500 years to partially guide science. It really does inform all kinds of experiments, even thought experiments. BUT, you might be right the trade off you propose is more worth it 2) Reichenbach's principle says any correlation must have a cause. Even without an idea of an on…
I really think it’s best to leave such metaphysical speculation out of it (or rather leave that to metaphysics.) Sure it could be right, and reality is definitely weird as hell, but it just seems like theology to me when you start pushing such things as fact when nothing says it is.
Don’t get me wrong I have weird beliefs about the universe too but I would always stress they’re my weird beliefs and not something we’ve proved. The many worlds interpretation is pretty mainstream at this point and it leads the masses to believe it’s either true or that scientists are batshit crazy. Not a good look imo.
Re: A physicist who bets that gravity can’t be quantized
#220I have always been fascinated by the problem of quantum gravity but, well, it somehow happened "too late", after I got also very deeply into "computing" (mostly HPC, GPGPU, rendering). Does anybody know if there is a way for somebody with my background to actually help/contribute in advancing this field?
Go work for a university in the physics department, they're always looking for help writing software ... of course it only works if you're willing to work cheaply ;)