The h Bar

ACuriousMind

15:02

@nickbros123 I think they are just looking for the Klein-Gordon equation

you're not expected to write down the square root and derive the Dirac equation here

@RyderRude I don't know what you mean by "in GR, the observed time would depend on the dynamical field"

what is "observed time"

the problem that there is no universal time coordinate occurs already in SR

Ryder Rude

The time that the clock of the experiment would measure would depend on the dynamical metric

ACuriousMind

what experiment?

Ryder Rude

Of the quantum gravity experiment

Where the theory is relevant

ACuriousMind

why is there a clock there?

Ryder Rude

I mean that the parameter of unitary evolution is getting entangled with the dynamic field

English usage of "entangled"

We compute unitary evolution wrt to a paramter that is supposed to be the observed time of the clock

ACuriousMind

15:08

what clock

Ryder Rude

This parameter is getting entangled with the dynamic field that the quantum theory is describing

Slereah

There's always a clock in GR experiments

ACuriousMind

nothing in the formalism relates the parameter intrinsically to any specific clock

Amit

Are you claiming that gravity violates unitarity?

Ryder Rude

@ACuriousMind the clock that we wud use to test the predictions of the theory

ACuriousMind

15:08

if you're saying that the time coordinate we use should be the time coordinate of some observer, that's true

but that's not quantum

when you solve the classical Cauchy problem in GR you're also starting with initial condition w.r.t to some time coordinate

and then you evolve those w.r.t that time coordinate

Ryder Rude

Yeah, that is true. But the time of the observer depends on the dynamic field across his worldline

ACuriousMind

why aren't you worried there that whatever you think goes wrong in the quanutm case also goes wrong there

Amit

@RyderRude peek gang: arxiv.org/abs/2104.03253

ACuriousMind

@Amit I don't think it is useful to randomly throw papers into the conversation just because they share a few buzzwords

Ryder Rude

@ACuriousMind in case of GR, we can just solve euelr langrange equation in some meaningless co ordinate. The proper time of the worldline can b calculated after we have already obtained the solution

In case of quantum, the dynamical eqn is the schrodinger eqn, which relies on the observes time

ACuriousMind

15:10

but that's not what we do

when people solve GR in practice they solve it as a Cauchy problem

i.e. give initial conditions and evolve

Amit

@ACuriousMind You are very correct, I'm sorry, I don't like to throw papers at anyone

Ryder Rude

This is weird. How can one know the time before we have solved for the metric

Oh i think i got it

ACuriousMind

either you think there is a fundamental problem with the notion of initial value problems in GR, and then this problem is both classical and quantum or there is no problem here

Ryder Rude

But not really :P

ACuriousMind

@RyderRude the point is that the evolution equations don't care whether the time is "real" or not

Ryder Rude

15:13

Ooh so they just solve it wrt meaningless time

And the real time can b calculated later

ACuriousMind

the parameter $t$ in the evolution equations is just that, a parameter. It doesn't have to be tied to a worldline - in fact, it never is because the time coordinate covers a whole patch of spacetime, after all, not just a single worldline

Ryder Rude

After we have the metric

ACuriousMind

and once you have the result, you know how to change coordinates and translate that result into the proper time of some observers if you need to

Ryder Rude

@ACuriousMind ok so this time-co ordinate has nothing to do with the metric we just solved for. Its just a parameter

Or does this time parameter agree with the metric?

ACuriousMind

I don't know what that means

there are infinitely many possible time coordinates for a given metric

it's just any coordinate whose direction is time-like

Ryder Rude

15:16

But i thought we were supposed to label it using proper time

ACuriousMind

label what

proper time is not a coordinate

I think you have misunderstood the nature of proper time

Ryder Rude

Ok i dont mean we need to label the entire spacetime using proper time

I just mean we label just the observer's worldline using proper time

And we can possibly switch to co-ordinates where the observer's wordline is a co-ordinate axis

Is this possible to do

So the proper spacetime is NOT a co-ordinate for the entire spacetime. But it can merely be chosen to be the time labels of our time-axis

If we choose our time axis to be the observer's worldline

Ok I think this gotta be valid. Becuz worldline is timelike and is infinitely long

Amit

I think it's only correct as a time axis for things that happen at distance zero from whoever is measuring that time, it is very limited in its use isn't it

Ryder Rude

Yeah, i need only that to be true

The rest co-ordinates can be meaningless

My point is that, in case of QM, the unitary evolution eqn must have THIS time as its parameter. So it wud depend on the dynamics. In the case of classical mech, we cud solve the eqn wrt ANY TIME

But in qm, we describe some observer's experiment. So we gotta use this specific time parameter for qm equations

ACuriousMind

@RyderRude worldlines are not necessarily infinitely long :P

Ryder Rude

15:26

. Imagine a family of astronauts :)

The generations continue the worldline

Lets just idealise for discussion

ACuriousMind

this was not a practical objection

you can have cases where some worldlines just terminate after finite proper time

Ryder Rude

Oh did u mean singularities

ACuriousMind

yes and no

Amit

I'm not sure what you mean when you say "THIS time", by symmetry, every time coordinate is the proper time of a certain reference frame? Isn't it?

ACuriousMind

but anyway it doesn't matter

Amit

15:28

$$\Delta{t}^2-\Delta{x}^2 = \Delta{\tau}^2 \implies \Delta{t}^2 = \Delta{\tau}^2-\Delta{x}^2$$

Ryder Rude

@Amit ye, but u gotta use the observer's time for QM equations. The observer who is doing the experiment

ACuriousMind

I don't know who "the observer" is in QM

the Schrödinger equation does not involve observers

and observers don't observe the time evolution of states, they observe the outcomes of measurements

Ryder Rude

Ok let's imagine u trying to test ur theory. U start with an initial condition. On paper, u predict the probbailistic outcome after a finite time. Then u run ur clock. At ur prediction time, u collapse

But ur predictions come out wrong becuz ur theory used the wrong time

Amit

ah I have an error in sign there

ACuriousMind

@RyderRude why did I use the wrong time?

of course if I did the computation in any coordinate system other than my own comoving one, I first need to transform the results into that one

in particular I need to transform the spacetime coordinates I used in my computation into my comoving ones

Amit

15:31

Should have used the other metric signature

ACuriousMind

but again there is nothing quantum about this

classical physics is also about observation :P

Ryder Rude

Ok so the procedure is the exact same as in GR

U compute unitary evolution wrt meaningless time

ACuriousMind

it's not meaningless!

It's just not some specific proper time of some observer

Ryder Rude

Yeah

So after u have ur solution, u also get ur physical time.

And then u transform to physical time

ACuriousMind

but that's just how time and space in relativity work - they're relative

the whole point is that we construct the theory in a way where we can switch between different coordinate descriptions without having to re-derive everything

Ryder Rude

15:34

But my problem is that, in the case of quantum theory, ur solution in terms of the "usless" time would not provide u information about ur physical time

In case of GR, ur solution includes a definite metric field

Thay gives u information bout ur physical time

In qm, u just got a wavefunction wrt useless time

And the metric is probabilistic!

ACuriousMind

the experimenter usually does not evolve themselves

we're outside of what we measure

Ryder Rude

That is a very good point

The observer exists in a classical metric. It's not probabilistic

ACuriousMind

like, you can't say "we're doing a quantum measurement" and then just evolve yourself and your measurement apparatus unitarily

Ryder Rude

Becuz if the observer's metric had meaningful quantum effects, the observer wudnt even be alive

ACuriousMind

that's not how measurements work

Ryder Rude

15:37

So the metric is probabilistic only for the experiment

Ok i think this solves it

But it also means that quantum experiments are only defined when the observer exists in a classical spacetime

So quantum mechanics sort of needs classical conditions to be meaningful

I guess we'll have to live with this :)

It would be very weird to talk about experiments if the observer is dead

Amit

That's talking interpretations again isn't it... not all interpretations accept that there is a real distinction between "classical" and "quantum" conditions

Ryder Rude

Yeah, but how do we define the time of unitary evolution without assuming a classical background time for the experiment to be performed? @Amit

The unitary evolution needs a definite parameter. The parameter isnt probabilistic

Amit

what is a classical background time? is time a classical quantity? I'm not sure that's a widely accepted view

Ryder Rude

Yeah u r right @Amit

But i dont see any solution

Slereah

The parameter time doesn't need to relate to the metric at all

It's just a coordinate

Amit

15:43

"Smooth operator... smooth operator...."

Slereah

U have general covariance, it works with any time coordinate

Ryder Rude

@Slereah that's a good viewpoint. But the problem is that schrodinger equation isnt form invariant under arbitrary transformation of time co-ordinate

Slereah

Qg theories are

Ryder Rude

So for unitary evolution, we cant have a meaningless parameter

Slereah

General covariance is prztty high up on qg list of priorities

Ryder Rude

15:45

@Slereah like, string theory?

Relativisticcucumber

hello, i am wondering about a quote in carroll. it says "the lorentz group includes not only boosts and rotations, but discrete reversals of the time direction as well as parity transformation.....what we really want is the set of continuous transformations (those connected smoothly to the identity)..." i am trying to unpack this statement. first, I dont understand why there is a specification that the time translation is discrete [...]

[...] and second i do not understand why we need to eliminate these from being possible transformations? i know that parity should be eliminated since it does not leave physics invariant, but why is the time reversal a problem?

Slereah

Sure

Ryder Rude

Ok but string theory so far only talks about scattering @Slereah

To deal with this problm, string theory wud need to talk about finite time evolution

Amit

It may be true that the involvement of time in QM is not done quite correctly... maybe that's how we ended up with the reverse time direction of anti particles (as far as the formalism goes apparently, I don't know if many take that seriously as a physical fact)

Ryder Rude

There's also covariant LQG which just gets rid of schrodinger equation.

Idk what the hell covariant lqg is describing

It's some foams. But idk about probabilities

Amit

15:48

@Relativisticcucumber He says that the reversal is discrete. I think it just means that there is no inherent thing in GR that prevents you from looking at the "lower half" of light cones, or in other words, the EFE are AFAIK completely time symmetric

@Relativisticcucumber It's a problem when you want to assign a direction to time... the continuous transformations prevent you from flipping the time direction, but technically I don't remember exactly how (something to do with the fact that the invariant interval can't pass through the null value continuously I think)

Slereah

You can flip the time direction but that is part of another connected component of the reparametrization group

ACuriousMind

@Relativisticcucumber "discrete " as opposed to "continuous" - there's just "reverse the time direction" and "don't reverse the time direction", but not "do an infinitesimal reversal of the time direction"

to answer your question of why you only want the continuous transformations I'd need more context

Ryder Rude

16:08

@Amit it's a very outdated formalism :P

Amit

Really? I thought it pops out of looking at the QFT expressions... but I don't know it first hand

ACuriousMind

@Amit another terrible misinterpretation of a straightforward technical fact

the technical meaning is CPT symmetry, and no, it doesn't imply that antiparticles are particles from the future

although it does mean that it is consistent to believe that

but there is a difference between a particular ontological interpretation being consistent with the formalism and the formalism actually directly stating something

Relativisticcucumber

@ACuriousMind okay i will provide more context tomorrow i am falling asleep sadly

@Slereah i will think about this tomorrow as well

Ryder Rude

@ACuriousMind i dont even get this as an interpretation of CPT theorem. Isnt CPT theorem just : The Hamiltonian commutes with the CPT operator?

How is that interpretation still popping out :P

ACuriousMind

It's unclear to me how serious Wheeler was when he proposed the one-electron universe but CPT + equal amount of particles and antiparticles would make it consistent

@RyderRude well, CPT means that a particle going forwards in time with some handedness behaves exactly the same as its anti-particle going backwards in time with the reverse handedness

so if you're silly (and we forget about handedness for a moment because people don't understand what it is anyway :P) you can technically use that to interpret all "particles + antiparticles going forwards in time" instead as "particles going forwards in time + particles going backwards in time"

because by CPT symmetry the physics of these two situations are the same

Amit

16:16

For whatever reason, time is not a "regular" observable in QM, I am wondering whether this can be easily justified

ACuriousMind

@Amit what's there to justify

it's not a "regular observable" in classical mechanics, either

just a parameter in the evolution equations

it's not a function on phase space

Ryder Rude

@ACuriousMind except for some stupid toy models :P

ACuriousMind

what

Ryder Rude

But in any case, time cant be an observable for just some specific models @Amit

@ACuriousMind i think there is a weird case like $P^2+X$. We were discussing it long ago

Amit

The momentum operator for example, corresponds to a position derivative (and vice versa). The Hamiltonian operator corresponds to a time derivative... but time isn't an observable (as opposed to position and momentum). Now this is proper nonsensical meta observation probably lol. But just from these shallow facts, I think a weird asymmetry is apparent

Ryder Rude

16:24

@Amit Ok i have a really nice way to interpret that analogy

Amit

Please sir go on

ACuriousMind

@Amit it's not a weird asymmetry

you can make it perfectly symmetric (make the theory "generally covariant")

Ryder Rude

Both time and space can exist as parameters of wavefunction. It is important to distinguish between parameters of wavefunction and arguments of wavefunction

Amit

@ACuriousMind Which would mean I would have an operator that corresponds to the time observable?

Ryder Rude

Time cant be an argument of wavefunction

ACuriousMind

16:27

@Amit the symmetric version just isn't, in general, useful

Ryder Rude

Space can be a parameter of the space translation schrodinger eqn

ACuriousMind

you just add a coordinate $t$ to phase space

but then in Hamiltonian terms your theory becomes constrained - the constraint is just what was the time evolution equation before that - and just everything gets more complicated for no reason

Amit

Does this mean that something like $\hat{T}$ will be a time observable proportional to $\frac{\partial}{\partial{E}}$ ?

ACuriousMind

the point is less that it's impossible to make time a phase space coordinate or operator and more that there's no useful way to do that

@Amit see, that's what doesn't work

when the spectrum of the Hamiltonian is discrete, something like $\partial_E$ makes no sense

Amit

Doesn't work in the sense that we don't know how to write anything physical as a function of $E$?

ACuriousMind

16:30

it's all a lot more complicated and ultimately pointless

@Amit no, doesn't work as in it's nonsense

doesn't mean anything

Amit

lol

user4539917

I was just pondering, could the laws of thermodynamics be different inside a black hole...

Amit

I think that any direction that can shed light on $W\tau\phi$ is time is interesting, but if you say this direction is nonsense in that regard, I take your word for it :)

ACuriousMind

time is what clocks measure

I don't find it any more interesting than space

Amit

You don't think that time may have some real quantum properties? In space we know what it means, that a particle can be in superposition in space but we never consider this situation across time

Ryder Rude

16:33

I think this stuff also conflicts with GR. Becuz the schrodigner eqn isnt form invariant under arbitrary transformstions of the time-parameter. If one is using the schrodinger eqn one must use physical time determined by the metric

So then we get into conflicts we just discussed

U wud need the experimenter's time to be classical for the parameter of schrodinger eqn to be defined

Then it all works out

ACuriousMind

@Amit I don't know why I have to say this so often lately but I'm really pretty satisfied with the physics we've already got

Slereah

You can make the Schrodinger equation invariant under reparametrization

If that tickles you

then it becomes a gauge theory

ACuriousMind

I just said that :P

just used "constrained" instead of "gauge"

Slereah

I didn't read

Ryder Rude

Yeah, u can do that for sure @Slereah

But the main problm is the the parameter has to be definite at least. It cant work with a peobabilistic metric

So the experimenter's time needs to be classical

Amit

16:36

@ACuriousMind Satisfied doesn't necessarily implies that you don't find room for improvement / advancement though :) I think what we have is lovely as well

Slereah

As I said, the metric doesn't change the time coordinate

Ryder Rude

Okay i got u now

ACuriousMind

@Amit No, what I mean is that I really don't see any necessity to believe QM is somehow "incomplete"

Ryder Rude

@Slereah i will need 2 think of another problm :P

ACuriousMind

I don't know what "time may have some real quantum properties" is even supposed to mean

user4539917

16:37

A grain of time.

ACuriousMind

what situation can QM currently not deal with that you think could be dealt with better if we answered that question?

Ryder Rude

Exactly @ACuriousMind it would be impossible to test experimentally. Cuz no experimenter can exist in non-classical time

But idk. For personal satisfaction, i guess a theorist wud look for such a "deep" theory

Amit

@ACuriousMind Ah, indeed there is no reason to assume it's incomplete. But this business about time for example, wouldn't necessarily fundamentally change QM, I would find it interesting enough if it would just allow us to draw new conclusions / predictions from QM as it is without changing it fundamentally...

ACuriousMind

as I said there are already formulations that treat time and space on equal footing

they're just ugly

but they're there

and there are good reasons for why they're ugly

Slereah

@ACuriousMind Mind your manners

Amit

16:40

Is there a "famous" example of such?

Slereah

Polysymplectic QM

ACuriousMind

@Amit I'm not sure what you mean by an example

Ryder Rude

Covariant lqg

It has quantum time too

Amit

Example of a formulation...

ACuriousMind

no, LQG is another different theory

it has nothing to do with what I'm talking about at all

Ryder Rude

16:41

But to test it, they say that they need to first construct a classical time using it

Slereah

CDT has discrete time IIRC

ACuriousMind

I'm just saying that there is a general procedure to turn any (classical or quantum) Hamiltonian theory into an equivalent theory that has time as a coordinate

Slereah

and causal sets

Ryder Rude

@ACuriousMind yeah, then u get constraints. But u still dont get quantum time

ACuriousMind

I describe the procedure for instance in this answer

it's just a boring technical thing, and the resulting theory is more annoying to deal with than what you started with in most cases

Ryder Rude

16:43

Covariant lqg has quantum time. But they say they need to construct classical time using it before they can predict scattering

ACuriousMind

@RyderRude I have no idea what "quantum time" means

when you quantize this constrained, generally covariant theory, you of course get an operator corresponding to time in the pre-constrained Hilbert space

but the time operator isn't gauge-invariant so it doesn't become an observable

which is how this evades Pauli's theorem

Ryder Rude

@ACuriousMind I mean time becomes probabilistic. So the fundamental version of the theory doesnt make any prediction becuz time of experiment isnt defined

There are some theories that try to do this

Slereah

why would time be undefined

ACuriousMind

I don't think what you're talking about has anything to do with what I'm talking about

Ryder Rude

Like covariant lqg

Slereah

16:45

do you have a citation for what you're talking about

Ryder Rude

@ACuriousMind yeah. U r talking about standard theories formulated in an ugly way

@Slereah yeah. I shall get it

6

Q: Is Loop quantum gravity an unadulterated quantisation of general relativity, or does it have additional assumptions?

I was reading this Phys.SE answer written by user346. At the end of point 3, they say they've only made a change of canonical variables from the ADM formalism to get the Ashtekar formalism. Then point no. 4 is about applying the standard Dirac quantisation on this theory. We end up with a Hilbert...

It's in the 4th point of the first answer I think

They talk about constructing a classical background

Amit

:63279371 Pirates of the Lagrangiean?

Ryder Rude

6

A: Does Loop Quantum Gravity predict general relativity in semi-classical Limit?

The confusion arises because there are essentially two different approaches to the LQG dynamics in the literature. The canonical approach pioneered by Thiemann is to define the matrix elements of the Hamiltonian constraint operator acting on spin networks, and then postulate the kernel of that o...

This other link is about an LQG theory that is known to reproduce GR

Slereah

not seeing anything about probabilistic time

Ryder Rude

They talk about superposing the lqg foam to construct classical spacetime @Slereah

So I thought the spin foam had probabilistic time

Slereah

16:50

does it

ACuriousMind

why would you think that :P

Ryder Rude

I shall quote the part :P

user4539917

@Amit I'll put that on the next play list.

Ryder Rude

It is not clear how the semi-classical limit of LQG works (and if it works at all). Currently, we do not even know two-point functions that would be somehow computed on semi-classical backgrounds.

Slereah

Isn't spin foam for the spatial part of GR for a start

Ryder Rude

16:52

No no

Thats usual LQG

Covariant lqg goes full crazy

ACuriousMind

I think you just have already some sort of idea how you want physics to work in your head and you're always interpreting the stuff you hear in terms of how it can be made to fit that idea instead of paying close attention to what people are actually saying

Ryder Rude

Lol

I swear there are two camps of lqg. The whole point of covariant lqg is to have a time foam too :P

Amit

The other alternative is also ok: forget what people are saying and write down your own theory :)

Ryder Rude

U can read about covariant lqg. It's not my confirmation bias :P

@Amit lol

user4539917

But, is it mainstream?

Ryder Rude

16:54

Hopefully, im capable to write my crazy theory someday

Even if its wrong :P

@user4539917 it is one of the two mainstream camps of lqg

U can read about it on the wiki main page of lqg. The two camps r in the intro

user4539917

Will do.

Ryder Rude

But lqg itself isnt mainstream, yes :P

user4539917

Later, then :-)

Ryder Rude

@Slereah @ACuriousMind Was I wrong on my interpretation of covariant lqg

ACuriousMind

I do not know enough about LQG to say for certain but it doesn't sound like what I think is going on there

and to be honest I don't care about LQG enough to find out

Ryder Rude

16:59

U r right that I have merely read a few articles about this theory

I cud b wrong :P

Slereah

looking at spin foam models I am not quite getting "probabilistic time"

$user image$

It would probably require some more explanations :p

Ryder Rude

Oh yeah. If time isnt definite, how can there be a probbailistic interpretation!

I should've said non-definite time

Amit

Very nice drawing

Ryder Rude

So u cant have a definite parameter for unitary evolution, thats it

In fact, covariant lqg isnt based on any previously known quantisation technique

So it makes sense that theres no schrodinger eqn

Amit

So covariant LQG dynamics don't evolve wrt time?

Ryder Rude

17:06

It just describes a foam as the "ontological" thing

There's no time. All that is obtained in the classical limit

Amit

It's hard to do physics without time evolution

Ryder Rude

And that's where u begin to make predictions

After taking the classical limit

The only plus of this theory is that it is known to reproduce GR

But its not based on canonical quantisation. So thats a minus

The other lqg camp is based on canonical quantisation. But its not proved to reproduce gr

Becuz the other lqg camp allows for an imaginary metric, imaginary distances, etc :P

So it has problems reproducing GR despite being based on canonical quantisation

Amit

It's all string manipulation isn't it, not a lot of physics without falsifiable predictions ^_^

Ryder Rude

Foam-manipulation :)

Amit

^_-

Ryder Rude

17:14

Strings are actually the rivals here :P

I dont yet buy either of these theories tho

Very unlikely anyone cud invent QG before experimental input

Amit

We do have some experimental input but I think since the current problematic observations are in astronomy it's a bit difficult to work with in comparison with controlled experiments

Ryder Rude

Yeah, and the dark matter stuff seems to b more related to classical GR than QG. It is generally believed that Standard Model + Effective Field GR describe everything until Plnack scale.

Amit

I don't know, if it's real new matter it can also be a particle physics thing

Ryder Rude

Yeah, but then it is expected 2 b matter that doesnt interact with electromagnetic field. Its not directly relates to QG

Y does my message get copied twice when i edit it

Amit

17:30

Maybe because you are logged in to the chat on several devices

Either way it's a bug, even if you are

Ryder Rude

@Amit @Slereah @ACuriousMind Is it common for people with phds to write new fundamental theories?

I'd expect everyone is creating their stuff

ACuriousMind

most physicsts don't even work near what you call fundamental theories

Ryder Rude

Oh yeah

Slereah

most of them just write about the physics of hot dogs or something like that

Amit

Not everyone have an insatiable need to disturb the status quo

Slereah

17:37

even in theoretical physics a lot of people will just do a boring thesis

Just study a particular case or something

Ryder Rude

People should be doing it just for fun tbh

Writing a fundamental theory

Slereah

I advise you learn it first

Ryder Rude

Yeah lol

I mean..other physicists who have learned it

ACuriousMind

honestly I think by quantity there are more crackpots than physicists writing fundamental theories

it's much easier to do when you're not constrained by ~~logic~~ the establishment

Ryder Rude

Thats true. I just think actual physicists should try this often too. It'd be wrong, but for fun, it's good

ACuriousMind

17:40

why do you think they "should" do it?

presumably those who find it fun already do it

Ryder Rude

I mean physicists have this apetite for invention

@ACuriousMind yeah

ACuriousMind

but most aren't the kind of specialists that understand what is actually necessary here on a technical level and realize they aren't gonna make any actual progress there

part of being an expert is knowing what you can't do

Slereah

if you're trying to make new theories before you know the old ones I have some suspiscions it will not go well

Ryder Rude

I dont expect it to go well even after learning it

ACuriousMind

@RyderRude so what? they do invent stuff! but in their chosen specialty

Ryder Rude

17:42

Lol

ACuriousMind

you really need to let go of this undertone that "fundamental" physics is somehow more valuable or real than what the vast majority does

Ryder Rude

The point is that u just do it for urself. Doesnt matter if its a bad theory

Even u urself dont have to believe in it

U just do it for the hell of it

Not that i'll try it before learning previous stuff tho

But my main point is that u urself dont have to believe in it either

Just do it as a fun DIY idk :P

@ACuriousMind i agree. Most time should be spent on useful progress

ACuriousMind

what

that's not what I'm saying

I'm saying that most people disagree with you that trying to randomly come up with fundamental physical theories is "fun"

Amit

Again, there's only so much you can do without experimental input... I think a lot of the motivation for rewriting physics simply comes from how temporally close we still are to all the latest revolutions in physics. There may be a slight illusion that these kind of things can happen more often than they really can... and again, that involves often ignoring the lack of the necessary experimental input

ACuriousMind

and that your claim that this is fun because of "invention" implies all the other forms of doing physics are somehow lesser or devoid of invention

Slereah

17:46

There's infinitely many things you can do without experiments

Ryder Rude

No. In fact, that other stuff is more valuable than what im suggesting

ACuriousMind

I didn't talk about anything being "useful"

just let people do what they choose to do

Amit

@Slereah Yes, but experience shows that they mostly don't lead to new fundamental discoveries doesn't it

Slereah

That never bothers me

Amit

@Slereah Yeah it shouldn't bother you if you have reasonable expectations, not everyone does

user250478

17:50

Hello to contributors of this chat, I add these references for my username user142929 of MathOverflow if you want to read (my attempts to get relations) about arithmetic billiards and prime numbers: you can to search in the browser of MathOverflow the key words arithmetic billiard, Goldbach conjecture, chirality, gnomon. Good afternoon physicists.

Amit

You're trying to relate billiard balls and prime numbers?

Slereah

they are obviously related

here's one right there

user250478

Yes, just an attempt @Amit I imagine prime numbers as the shape L.

Amit

Ah! Thanks @Slereah don't know how I missed that one

ACuriousMind

what

Amit

17:53

Numbers have shape?

Ryder Rude

Ok i got something about this but its long shot

Pi shows up in number of collisions of blocks due to conservation of energy/momentum stuff

user250478

Just a moment and I add a reference from MathOverflow and a draw from this post @Amit

Ryder Rude

And u can then relate pi to number theory stuff

There's connections with primes

user250478

I imagine prime numbers as the figures F1, F2 or F3 from imgur.com/a/TlmdwHi that is one of attached file for my post Arithmetic billiards, prime numbers and the Goldbach conjecture this mathoverflow.net/questions/429420/… @ACuriousMind

Amit

It appears like an illegitimate use of a SE question

ACuriousMind

17:56

@user250478 I see. Please don't ping me about this anymore.

user250478

I'm sorry if I bother you.

Good afternoon.

user 85795

Cya

Mr. Feynman

@Relativisticcucumber I don't know

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