00:00 - 18:0018:00 - 00:00

12:00 AM
@danielunderwood r u interested in working on a side project w/ AI and AR
I can't pay or anything of course, but we could work on it together lol

depends
is it cool?

12:31 AM
it could be
I dunno

12:54 AM
Got any details? I've been wanting to do something in the ML/AI side, but haven't really had a clear goal to go after.

1:16 AM
@WhitePrime This is a very misinformed perception of the Big Bang
Our modern physical theories break down around 13.7 billion years ago because the conditions of the early universe are too extreme. Temperature, density and gravitation go to infinity at a moment dubbed (poorly) the "Big Bang".
Cosmology makes no predictions about what happened at this point in time, it's a big open question in physics. Nor does it claim that everything was "created" at this point in time, or that everything was "packed into the size of an atom" (the universe is infinite, mind you). We know nothing about this moment.
*correction: the universe is probably infinite, but either way it has nothing to do with matter being packed into any region

1:39 AM
@SirCumference time flies, yeah
it's a little crazy.

2:26 AM
@danielunderwood we can chat in pms? are there pms on here...

3:17 AM
@enumaris I don't believe there are, but I have an email at protonmail.com that's my name here

3:28 AM
o.O
protonmail?
like danielunderwood@protonmail.com?
what site is that lol
u have wechat?
or...gmail? gmail has a chat too

4:02 AM
I just stumbled upon this recent comment thread by Luboš & safesphere on an 8 year old question. :facepalm: physics.stackexchange.com/a/3586/123208

2 hours later…
5:35 AM
I cri everytime

5:51 AM
safesphere has some... interesting...viewpoints

Sorry, phone problems here. Let me try again...
I've been having serious problems with a recent thing I made. Now I wouldn't be asking this question unless it has me at a standstill. It has to do with my metal melted. For those who don't know what a metal melted is. Google "metal melted project by the king of random". His channel should cover what it is in general.
I've asked on the EE.SE site. I'm not getting any answers besides confused answers. The results and the formulas used to calculate the watts is not matching up. It runs on a 20 Amp 123 volt breaker. I put in the right and correct values and it gives me an impossible wattage usage. Such as my breaker can only handle a certain amount of watts, but the formula tells me its a thousand more watts higher. It makes no sense.
I've been pulling all nighters to figurr this out. But now I've come to nothing but no conclusions, dead ends, no guesses, no possibilities, as well as no where to figure this problem out. It is not a in the book Q&A. Its very complicated.
I'm asking for help or any form of insight on my problem, this includes wild guesses. I'll post a picture of a document tomorrow evening MST U.S. That tells you everything and all of the information. Its late here and I have to be at the top of my game tomorrow. I need all of the help I can get on this one. I'm just burned out trying and trying to figure this out.
Being burned out like this isn't what I usually do. Lets just say it takes a lot to get me burned out like this. Good night everyone. Talk tomorrow evening.
I apologize for the typos I made.
Google "metal melter project by the king of random" typo, sorry. And I meant metal melter.

6:23 AM
@enumaris I'm guessing it's the email service used by physicists :P

weird

1 hour later…
7:41 AM
@ScientistSmithYT Do have a link to the question?

you know I'm thinking we could make the standard model look much much worse if we considered that there was only one matter field and one gauge field
Make the matter field some $\mathbb{C}^{13} \oplus \mathbb{C}^{13}$ and the gauge field $\text{SO}(3,1) \times \text{SU}(3) \times \text{SU}(2) \times \text{U}(1)$
Plus the Higgs field I suppose
There's no fundamental reason we have to split the matter field just because the gauge fields are direct products
Just have some awful vector bundle $$V = \mathbb{C}^{11} \otimes (\mathbb{C}^2 \oplus \mathbb{C}^2) \otimes \mathbb{C}$$

8:15 AM
Hm
What's a good definition of the Lorentz group, independant of representation
Is it that given a vector bundle, the symmetry given by diffeomorphisms preserve the norm induced by the metric?
Not 100% sure how to define this properly
How do you define a norm on every vector bundles given the norm on your tangent bundle
I'm pretty sure the solder form should be involved somewhere
I guess perhaps just given a solder $\theta$, $X,Y \in TM$, $$g(X,Y) = g_V(\theta^{-1}(X), \theta^{-1}(Y))$$
Or something

9:01 AM
3

That's overrating engineers.

Lorentz group is just a group defined via a set of operators on an inner product space, bundles are too special to the concept of a manifold

@bolbteppa It has to be the same group for all tensors and spinors, though
up to a rep

There's no rep involved in defining the Lorentz group
It's literally defined as transformations on 'position' vectors preserving the norm, it does seem rep-y
I mean it's just $\mathrm{O}(1,3)$ right, any issues with defining it are also problems for all orthogonal groups
They are all defined with respect to some $\mathbb{R}^n$ and an inner product on $\mathbb{R}^n$

9:29 AM
But isn't the Lorentz group also defined on tensors

It is - they transform as products of vectors, where the Lorentz group also acts on vectors other than $\mathbb{R}^4$ vectors (e.g. the EM field), i.e. representations

9:46 AM
would what I say be equivalent to it, though

10:01 AM
Hm wait, I guess not
Oh well

@Slereah I don't really understand what you're looking for here. The Lorentz group is (isomorphic to) the subgroup of 4x4 matrices that preserve the Minkowski metric under conjugation.

11:08 AM
Oh gooood

11:21 AM
Although at least apparently there's no nonlinear representation of the Poincaré group if the number of dimension is > 3
But there is one for $1,1$ Minkowski space
And $1,2$

11:35 AM
Guys, do you ever think you're immersed too deeply in the maths of it all. Does the maths genuinely excite you? That's so weird to me (with the utmost due respect).

I wouldn't advise a career in theoretical physics then

I'm certainly nowhere near knowledgeable enough for a career in physics. What interests me is the physical reality etc of the universe

Doing the actual physics properly is also quite harrowing, tbh

TIL the USSR was the first to reach the moon
how's that^ for "physical reality" :P

Also I'm not 100% sure what is meant by "the physical reality" here
I am quite suspiscious when terms like that are used
I'm not sure this refers to "What measurements you get after previous measurements are taken" or "Maybe we are all made of very small springs"

11:45 AM
> "reality" is an illusion, albeit a very persistent one :-)

("Things are made of very small springs" is one of those popular crank theory with engineers because engineers understand springs)
a lot of crank theories are just attempts to make physics into something using simpler physics, really
Springs, fluids, electromagnetism

By physical reality, I mean just that. You theoretical physicists have instead woven a web of assumptions and essentially meaningless mathematical equations

You mean just what?
you did not actually answer the question

I'm no conspiracy theorist or anything like that. Though I'm skeptical of black holes and the Big Bang theory.
Also, I still find it stunning that you believe time is an actual thing, capable of being deformed etc.

do you know what physics actually is

11:52 AM
There's a difference between physics and theoretical astrophysicists, bro. I'm not trying to be a smart arse, or anything, by the way

You have literally answered none of my questions

do you mean "reality" is what you can perceive with your "senses"?

Reality is reality. Things made of matter or energy.

Well apparently you are certain enough that energy exists
Which is not a quantity you can actually measure directly

also, "things"?

11:56 AM
The point of physics isn't the reality of whatever model you are using
You take measurements, you convert it into data acceptable by your model, and then you perform calculations until you get other measurable quantities
Whether anything between the first and last step is "real" isn't actually part of physics
I don't know if general relativity is real in any sense but it does offera mechanism for all known experiments
If you think you have another model which also explains all the data then that is fine

Rather than fitting your models with observed reality, you guys change reality to fit your models. One example: We keep seeing fully formed galaxies that're older than 13.7 billion years. But you hand waive it all away.

Although both would be acceptable models unless you have another experiment which doesn't fit the data for GR

That's just one example of many, lads.

How do you know that they are older
There's no direct measurement of the age of a galaxy
That quantity is entirely model dependent

I know it's ludicrous to give the universe an age, when infinite empty space has clearly always existed.

12:00 PM
Trust me if anything I am more distrustful in the other direction
I'm more worried about the data being interpreted in the FLRW model instead of a more general framework

*Wave not waive.

Instead of making it more like classical physics
Your problem is basically that you're confusing "observed reality" with the naive classical interpretation that one would get from it

Bro, to be honest, you've not caught me at a deep-chatty time. Otherwise I'd argue these points.

The raw data we have is just various light signals on a grid
Neither distances nor ages are measured directly
The interpretation of those dots into distances and times are part of the theory itself
Assuming Euclidian geometry and a fixed speed of light is just as much of an assumption as GR

^for when you have "deep-chatty" time

12:09 PM
I could do epistemology wank all day long
It's fun though not terribly useful past a certain point
Can we really trust reasoning by induction 🤔

yeah, diminishing returns...

@Slereah where does it say the > 3 thing

@bolbteppa another paper
Apparently you can do the Lorentz algebra with sines and cosines in 2+1 dimension

@WhitePrime evidence is a stubborn thing

You could perhaps find a theory that could explain those data in a different framework, but there aren't a lot of theories that explain all the gravitational data
And the only ones that do so far are basically GR up to a very small extra term

12:18 PM
@bolbteppa Thing is, you guys have everyone believing that black holes are incredibly dense objects. The media always describes them as such. In reality, under the hand waving, you admit black holes don't actually contain any matter at all, and that that they're basically made of spacetime curves or something.

People really tried hard to show GR wasn't true, we don't lack alternative ideas
Real black holes are a complicated affair

Clearly

That's why you're supposed to read real textbooks if you want to actually understand it

Honestly I wouldn'teven try discussing what real black holes are like in GR even though I've been studying GR for years
You need the mystical art of perturbative and numeric GR for that

Then there's all this black hole evaporation stuff

12:20 PM
Also black hole collapse!

and information on the boundary etc

Did you know there are dust collapse solutions which just lead to naked singularities

@WhitePrime the first level understanding is basically a final year undergraduate general relativity course, without that you are going to be talking nonsense beyond the pop sci level, it's just the reality of this stuff whether one likes it or not

My point is that I don't know enough experimental GR to properly defend it but I know enough to know that I wouldn't attack it without quite an extensive background in ot

To understand GR, though, you have to throw away all intuition and common sense.

12:23 PM
The next level is probably a good cosmology course
No you don't throw away intuition and common sense, you just refine your incorrect (out of it's domain) low-velocity intuition to high velocities and the consequences of this which are non-obvious

@WhitePrime intuition and common sense are fairly empty words
Classical physics was considered very unintuistic once upon a time
The obvious intuition is that the earth is immobile and flat

and there's a warm wind blowing the stars around :P

Sky men are moving the stars

It's very simple, we imagine gravity propagating infinitely fast, but experimentally nothing propagates infinitely fast, it takes a finite time for interactions to propagate, however Newtonian mechanics is built on instantaneous interactions, so we need to start over assuming a finite speed of interactions, re-doing Newtonian mechanics in an inertial frame assuming a finite speed for interactions produces special relativity, and it's just a small step to general relativity from this

Get ready to be triggered, bros: General Relativity has probably set us back a hundred years in regards to understanding the universe.
I say that with politeness etc, and due respect.

12:33 PM
::shots fired::

and because gravitational fields are such that all bodies move in them the same way (regardless of their mass) if the initial conditions are the same, we note that free particles in an inertial frame would all also move in the same way from the point of view of a non-inertial system, the principle of equivalence, which lets us set up the theory of gravitational fields using the properties of special relativity in non-inertial frames
@WhitePrime I think it's your understanding of gravity that is probably a hundred years back ;)

I admit, that was probably a really stupid thing I said there.

why did you say it?

I kinda half meant it. Well, a quarter.

Well, you're wrong about that quarter man

12:37 PM
If you have an alternative theory that explains all of this it would be appreciated
5

Here's a list of various effects then (I might add more later on) Measured effects for special relativity : The constancy of the speed of light, as measured by the Michelson-Morley experiment. Time dilation/length contraction of two observers in motion relative to each other, as measured by co...

@Slereah ugh, French colons

I have no alternative theory.

Well that's the thing really
People interested in physical reality are quite often not that into explaining physical experiments

Why has GR set us back

Do you guys genuinely believe the matter of at least a trillion galaxies was once packed into a speck smaller than an atom?

12:41 PM
Why not

I don't know, I just know it fits all known observations

How can you say 'why not'.

Also "that doesn't sound plausible" isn't really a great argument

how can you say "genuinely believe" without proper justification?

Imagine even trying to compress an house-sized block of steel into a atom.

12:44 PM
The fact that we don't have the technology to do the same compression as an entire universe isn't really a good argument
We don't have the technology to make a sun either

The forces between the particles making up that matter travel at the speed of light through space, when the space they live in curves up so much there's nothing the forces living in that space can do but go with the space
That's the whole black hole idea, that space curves up so much nothing can escape the region, not even light

(removed)
plz
;-)

The only reason the periodic table goes up to like 120 or so is because the forces needed to push more atoms closer together can't be attained, why can't it go higher?

Do neutron stars count as nuclei
They'd be pretty far off on the table

A neutron star is the collapsed core of a giant star which before collapse had a total mass of between 10 and 29 solar masses. Neutron stars are the smallest and densest stars, excluding black holes, hypothetical white holes, quark stars and strange stars. Neutron stars have a radius on the order of 10 kilometres (6.2 mi) and a mass of about 1.4 solar masses. They result from the supernova explosion of a massive star, combined with gravitational collapse, that compresses the core past white dwarf star density to that of atomic nuclei. Once formed, they no longer actively generate heat, and cool...

12:47 PM
Also as said

"In popular scientific writing, neutron stars are therefore sometimes described as "giant nuclei". However, in other respects, neutron stars and atomic nuclei are quite different. A nucleus is held together by the strong interaction, whereas a neutron star is held together by gravity."

I don't have that much emotional investment in big bang cosmology

@Slereah Depends on whether you think a "nucleus" should be held together by the nuclear force or not :P

If there's an alternative theory that explains all the facts, that's fine
It's been tried a lot and so far none of them really managed it

In fact, let's go balls-to-the-wall: Imagine trying to even compress a sheet of A4 paper into an atom. Then marvel at the gorgeously violent difference between a piece of A4 paper and all the matter in the universe.

12:48 PM
@WhitePrime how do you know reality doesn't change with scale?

@WhitePrime have you tried
With all the matter in the universe

Can't say it doesn't work until you've tried

No one is claiming that all the matter in the universe was concentrated into the "space of an atom". The universe has always been infinite.

If your criteria is "Can it happen on earth", I think you'll find cosmology a fairlynfrustrating field
Look at @ACuriousMind thinking he knows the topology of the universe

12:51 PM
@Slereah Append ("in standard Big Bang cosmology") to each of my statements :P
And since we believe quantum effects dominate over GR for the first few moments anyway, in fact no one is claiming to know what happened directly at the beginning.

that too
also man
if you think big bang cosmology is bad
wait until you've read Newtonian cosmology
I've read a ton of papers detailing why Newtonian cosmology is terrible
Even in the 19th century people knew it didn't work

Doesn't inflation say the matter in the universe was once in a region even smaller than an atom? :p

@bolbteppa Well, if the universe is $\mathbb{R}^3$, then it was also that before inflation
although of course, the observable universe was in a region smaller than an atom at some point

@bolbteppa Perhaps you mean observable universe?

I'm just going on pop-sci recollections but I'd be shocked if it wasn't saying this tbh

12:55 PM
you know
My favorite thing about pop science is my childhood book on black holes

Of course it does actually
In physical cosmology, cosmic inflation, cosmological inflation, or just inflation, is a theory of exponential expansion of space in the early universe. The inflationary epoch lasted from 10−36 seconds after the conjectured Big Bang singularity to some time between 10−33 and 10−32 seconds after the singularity. Following the inflationary period, the universe continues to expand, but at a less rapid rate.Inflation theory was developed in the late 1970s and early 80s, with notable contributions by several theoretical physicists, including Alexei Starobinsky at Landau Institute for Theoretical Physics...

That book basically said "We don't know what could come out of a naked singularity, even a wild cat could come out!"

I have a small question I am high school student, I am reading shm now a days, when I saw T=2pi/w for a particle in one revolution (I am taking projection of shm on circular motion), is this interval is equally divided among 4 quadrants

with that illustration
and you know
when I grew up
I thought this was probably an exageration
But then, I read actual serious papers on naked singularities
and they were right!

What I mean is is this time is equal divided like 2pi/4w

1:01 PM
If I had to guess what was wrong or not in that book, my guess would not have been that the cat singularity was correct

Hi, anyone aware of a tool for MANIPULATING units and I mean units and not the values
e.g. when I give "[Tesla]" it spits out [kg s$^{-2}$ A^{-1}$] and the like Have you tried asking WolframAlpha? you want to manipulate joule 1:16 PM You can also just look up the official SI document there's a giant list of units and their equivalent dimensions @yuvrajsingh thats nice ! or just wikipedia, really linux "units" is also fairly OK @Slereah no thats BS @Rudi_Birnbaum I didn't, t get you cant play around there go from cgs to SI and so on. 1:21 PM Sorry 2:16 PM @enumaris if you want gmail, firstname.lastname13@gmail.com 1 hour later… 3:22 PM Please any one can share his comment on question 3:42 PM Hi, everybody. @DanielSank hi congrats on achieving quantum supremacy™!!! :) :o o_O that's a big old lie obviously At most they solve it faster @Slereah feel its a bit )( misleading also. it appears the claim is based on that a classical computer cant simulate a "sufficiently complex" QM computer "afaak" ("as far as anyone knows") Very dumb Turing himself literally wrote a paper on probabilistic Turing machines in the 30's And immediatly saying that they have the same computing power The proof is very short and it's easy to see why You just simulate every possible path It may be much more expensive, obviously IIRC you may need up to$2^N$bits to simulate$N$qubits But that's at most yes was chatting with MoreAnonymous about this recently. the "quantum supremacy" concept seems not based on the fundamental idea of Turing completeness. in addition, QC computers face the noise problem. it could be close to a "dealbreaker" for QC. however, am still rooting for them for over 2 decades now :) 3:57 PM @Slereah Well, one should read the "unsolvable" there as "infeasible with current technology", not as "in principle impossible". @vzn Quoth the very article you cite: > A Google research paper was temporarily posted online this week, the Financial Times reported Friday, and said the quantum computer's processor allowed a calculation to be performed in just over 3 minutes. That calculation would take 10,000 years on IBM's Summit, the world's most powerful commercial computer, Google reportedly said. @ACuriousMind need to look at their paper but they seem to blur/ mixup the idea of "calculations". an evolution of a dynamical system is not exactly the same as a "calculation". think they have blurred this concept. think (partly) Martinis needs a bold marketing slogan for the 10s of$Millions spent and Quantum Surpremacy seems to resonate well in the media o_O

didn't IBM also report something saying that they had the best QC this week?

@danielunderwood havent heard of recent announcements but they are indeed competing with google both indirectly + directly on this. anouncing qubit counts is now almost like Intel vs AMD announcing latest cpu speeds...

@vzn "Evolving a dynamical system" (namely the system of qubits) is exactly how a QC is supposed to perform computations!

@ACuriousMind am aware of that. but not every "evolution of a dynamical system" corresponds to a useful algorithm. notice how they dont immediately name the algorithm that has attained QC supremacy. the ultimate goal is to attain supremacy with TM simulation ofc. that is probably a nearly magical goal... (ie something worth thinking about but not actually attainable...)

4:06 PM
@danielunderwood Given that this appears to be based on a "leaked" paper Google didn't actually want to publish yet, one should probably await their actual publication.

@ACuriousMind why wait when you might be able to affect stock prices now?!

lol! :)

Heh

@danielunderwood IBM has an open science simulator + open (public) timesharing option, defn a big plus over google.

meanwhile @DanielSank is wondering what he's done just by saying hi

4:17 PM

The following is a demonstration that one knows the "answer" except the answer is surprisingly unsatisfactory
0

In 1st year chemistry questions, the concept of acid strength is often introduced to students including the 3 factors that provide a heuristic explanation for most of the common acids and conjugate bases: Electronegativity of the atom directly attached to the protic hydrogen, resonance stabilisat...

Critique of the answer if you may

ooh, I already know the answer from my short time in a mega-corporation! Any views or opinions he has are not representative of his company, blah, blah

That's the joy of chemical education: Finding blindspots in 1st year chemistry curriculum

@WhitePrime Sigh again, that is exactly not what the big bang is
Arguments like this make me cringe

@danielunderwood are you currently at a mega corp? prev? which one?

4:42 PM
I better submit requests to HR and PR to disclose that info

lol now reminds me, once ran afoul of BigCorp™ disclosure rules, not a pretty picture, defn cant talk about it either :o o_O :P

@Loong I don't. I haven't asked my question on the main site yet. I haven't asked it on the main site because it's a question I need answers on. Not criticism on. I'll have everything I can find and think of that I've found all put on a document so you can read. I might have it done earlier than usual due to other circumstances.
@rob I can't track down the source I had a while ago I'm sad to say. I've looked for so long.

5:01 PM
@SirCumference Bro, it's possible it's making you cringe because of how mad the Big Bang theory looks when a light is shone on it's very shabby body.

@WhitePrime Literally no one knows what the Big Bang is, as I've explained
It's an open question in physics what happened 13.7 billion years ago
All we know is that everything in the universe was much closer together, and at much higher temperatures
Your interpretation seems to be from a mix of popscience information and an anti-science bias

Lel! Anti-science bias?

Yes. At least that's what I'm getting from your comments of GR, a theory you evidently haven't studied (as it would fix a lot of your misconceptions about cosmology)
5 hours ago, by White Prime
Get ready to be triggered, bros: General Relativity has probably set us back a hundred years in regards to understanding the universe.
Like come on :P

I did later admit that comment may have been a tad silly.

reminds me of the weekly article that I see that seems so surprised that "GR still holds after X discovery"

5:15 PM
Just in general, you're are setting up strawmen as science and trying to argue against them
No one says anything about the "size of an atom" with regard to the early universe
As you've pointed out, that doesn't make any sense.
I'm also almost certain that we've never found a galaxy for which the lower bound of its age is greater than 13.7 Gyr

@WhitePrime there are eminent/ authoritative scientists who are working on revising GR but the media largely hasnt interviewed any of em... yet o_O

@vzn Interviewer: "What progress have you made in revising GR?" awkward silence

@SirCumference lol!

5:38 PM
I had a vague idea of a quantum gravity theory which I don't think has been done
But I kinda gave up on doing it
It seemed hard
And from general argument, probably wrong

@ACuriousMind I see you have a new song

@RyanUnger I have?

Isn't it a bit weird, though, that we haven't yet progressed from a 100 year old theory? (GR)
And let's not even get started on Gravitational Waves. Those alleged ripples in spacetime that are 300,000 times smaller than a proton. I mean, they could be literally anything.

5:55 PM
@WhitePrime No, they can't. Try reading some of the papers before making those claims

300,000 times smaller than the nucleas of an atom. They could be anything.

@WhitePrime Frankly, if you just want to rant uninformedly against established science, you can go do that elsewhere. We have detected these waves, and there's plenty of literature on how we did that.
3
There's no meaning to saying that a wave is "smaller" than a proton. Their effects may be miniscule, but LIGO has seen them.

@ACuriousMind Very hostile, bro.

He isn't being hostile. It's very clear that you haven't read the papers you profess are incorrect, and it's a matter of fact that the waves have been detected
You're not going to "convince" anyone here of your claims based on this

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