muruep00

4 minutes ago, Ghideon said:

Current models predicts how black holes behave but does not rely on what is inside a black hole AFAIK. We can speculate what is inside given the current theories, theories that we have supporting observations for. 

Note: "proved right" might not be the best way to say it. We rely on supporting evidence when theories are accepted. 

 

Yes, I totally agree. You may ask Markus if he also agrees in the fact that current model for black hole interior is speculative

Question now is, how can a scientific approach handle this problem? Well, I think proposing consistent alternatives have to be done, to begin with. And one of my main question in this post is, why has anybody worked out an alternative interior to black holes just using GR? And I dont refer to the models beyond the singularity, which may be regarded as interior models as well, but alternatives to the problem GR faces inside, the singularity. We could do that instead of waiting for a 100 years stuck on the belief that quantum gravity theory should solve the speculative singularity.

To the not: You said it better than me.

Quote

 tell us how to indirectly observe the inside of black holes.

For the time now, we cant, in the actual model of black holes and in mine.

Quote

*) Also note that the arguments surrounding your idea begin to look very similar to religious ideas and beliefs, intended or not. I'm not going to further push that discussion, feel free to open a thread in the correct section. 

Well, I believe the actual model is more religion-related. Mine is just a proposal, nothing more, a hypothesis to be simulated. Nowadays model is not even proved right, and everybody believes in it.

3 hours ago, joigus said:

Which EM interaction would do that?

Photons?

Magnetostatics?

Electrostatics?

EM always vanishes at even moderately large distances.

The picture of a supermassive black hole's interior as a nice habitable place has sent shivers down my spine.

And your suggestion of sending physicists past the event horizon has reminded me of this line by Scottish comedian Danny Bhoy:

"They say crocodiles can be faster than horses. I don't know how many horses it took to find that out."

It was just a curiosity, I quote Bonnor: http://www.januscosmologicalmodel.com/pdf/bonnor1989.pdf

Chemistry might be a very interesting subject in this universe. Moreover, positive atoms would attract each other, and so 3 Coulomb's law is unaltered, in particular, in sign.  would negative atoms. In this way large condensations, each with a positive or negative charge, could form. In fact, charge would take the place of gravitational mass in the formation of large bodies. Although there would be no neutral planets orbiting stars under the force of gravitation, there could be charged planetary systems. Intelligent life in such a universe could not be ruled out.

1 minute ago, joigus said:

Proving to whom?

To whoever goes inside and perfomes the experiment willing to know what lies inside a black hole.

I was saying that the black hole interior isnt something that is beyond the scientific method because it is impossible to observe. Some physicists like Sabine Hossenfelder think that this issue takes places with the Multiverse interpretation. But interior of black holes certainly are objects of study and application of the scientific method.

Just now, joigus said:

Are you serious?

I just wanted to point out that you can also be the one perfoming the experiment and proving whatever lies inside an event horizon yourself. Ghideon only talked about probes, which of course would need to send that info out so that a physicist can interpret the experiment done inside.

17 minutes ago, Ghideon said:

I don not worry about delivering the probe to a black hole or the probe passing the event horizon and turned into inflating negative matter. I ask: how do you get the results back out. No result=no observation/no evidence. Getting the result back is not limited due to current technology, it is completely impossible due to the theory you have used in your idea. 
 

 

If you were inside the probe, why would you require to send the info out?

This is again speculation on a speculative idea, but supermassive black holes might even be a habitable place, although no planets could be created with repulsive gravity, unless some electromagnetic interaction holds them up.

I get your point, but I think the fact that no direct observation can be made for now, is something we encounter every day in QM. Can you measure directly the wave function of a particle? No, you just believe that there is a wave function when you do not collapse it because the model that we have that describes better the direct observations we can make in the quantum scale require them! That is an indirect observation pointing out the existance of something unobservable, just like the one I proposed in my first post.

Your skepticism about the fact that I use negative matter that can be directly seen, can be compared with skepticism about the fact that QM requires the assumption of unobservable wave functions for particles, which must exist when you dont measure and collapse them (this I far as I understand QM).

30 minutes ago, joigus said:

Just because you're a mechanical engineer it doesn't mean that you can't come up with an good idea. Actually, being an engineer you're in a better position to do so than many amateurs. But if you want to push your idea any further, you should be your first critic. Try to find things that could be wrong. Is energy conserved for a particle falling through the horizon? And angular momentum? Mmmm... really? Energy is not conserved in GR in the usual way. But for small test particles moving in a metric it must be. Can I make the fundamental invariant (proper time) go through the horizon continuously? Actually, the more there is of value in your idea, the more worth it it is to put it to the test for consistency. It's the best way to find possible modifications that might be needed. Or saving lots of time invested in an idea that's not worth pursuing.

Saying that continuity, differentiability and injective character are essential in microphysics is no understatement. Discontinuities only appear in physics in the thermodynamic limit (phase transitions).

Take some time to learn about the Lagrangian and Hamiltonian formalisms, and then Poisson brackets. They may look like gratuitous sophistication to some people, but they are very important in theoretical physics, and illuminate very important relationships. And then go through some primer on QFT. Enough to be going on with. The deep connection between symmetries and conservation laws, discrete symmetries, how they are different from continuous symmetries...

And, above all:

 

Thank you for your advice joigus. I will keep learning in order to deeply understand GR, at least to the point where I can defend my idea (or new ones, maybe). For the time, im not planning to study QFT.

I think you took that picture from Gerardt Hooft's website: https://www.goodtheorist.science/ It is a nice work of his, that I know of.

greetings

6 minutes ago, Ghideon said:

To be blunt; checking if your idea is unscientific or not. First; the result from the thought experiment discussion seems to be that an alternative model, created according to the same rules as your model can’t be distinguished from your model.

I think you cant develop a consistent model which gives the same predictions as mine with the physics that we know about (GR & QM without quantum gravity). You may even see that my model is very constrained.

6 minutes ago, Ghideon said:

Now let's check scientific vs unscientific:

List of what I find in the tread so far:
-The only way to perform an observation supporting your idea is to enter a black hole. 
-Your idea accepts GR which per definition means there is no way, even in principle, to get any information back from the hypothetical observation done beyond the event horizon.
To further complicate observation:
-Even if a probe could, by some exotic means, communicate back from behind the event horizon (which is in principle impossible according to GR and your own descriptions) the probe would have turned into negative matter when it passed through the event horizon. 
-Your idea states that the properties behind event horizons are unique; it is there, and only there, we will find negative matter, negative gravity etc.

According to your presented facts, as I understand them*, this has the following consequences:
-A probe, sent into the only region in the universe where the test can be performed will:
1: Turn into negative matter (and also inflate) once the probe passes the event horizon.
2: Have no means what so ever to send anything back to an observer outside of the black hole since the probe is beyond the event horizon.

I do not know if this is your intention or not but from the description so far you have created a scenario that is in principle completely impossible to get supporting observational evidence for. Isn't running some simulation as the only possible support for the idea very close to unscientific? 

I agree in almost everything. I think you underestimate indirect observations & numerical simulations regarding my model, but let me make a point clear:

You cant define an hypothesis to be unscientific just because our limitations of technology. That is, my model can be perfectly proved by going inside a black hole, its not methaphysics, its the real world. For now, our techonology is not capable to send a probe into a black hole. But the hypothesis is scientific, it is just that were are limited techonologically at the moment. It is like telling Einstein that gravitational waves cannot be proved to exist, just because they are very difficult to observe. And 100 years ago, even Einstein himself did not think they would be measured in the future. But we do measure them now. To put it simple, unscientific ideas have nothing to do with the limtations of techonology. It is a question of whether they can be proved or not, today or tomorrow. If my model stated that you cannot enter a black hole (just a silly example), then that model would be unscientific, because no matter which technology you have, if you cant go inside you cant prove it at a high level of certainty, never.

But anyway, leaving this point appart. I believe numerical simulations, if carried out leaving little or non room for mistakes, and the predictions of my model matched precisely the observations that we currently cant explain, at least, it would be reasonable to consider my model as viable as the nowadays model (Markus model). Because I remind you that the actual model of the inside of a black hole, is not proved to be correct.

What you are telling me, I already know and Im already aware (in fact I like a lot the philosophy behind science). Unfortunately, black holes may be one of these objects, together with matter that seems to not interact with light, that set the biggest challenges in proving them right.

Thank you Ghideon

51 minutes ago, joigus said:

I mean loners, solitary BHs that have been ejected by the centrifugal potential barriers. There are bound to be many objects like that in the universe. Not only BHs. For those unfortunate wanderers, there is no accretion. Only a future of perpetual evaporation (if Hawking is right). 

OK. So I'm counting your answer as maybe there is, maybe there isn't.

We know it must be anti-unitary because it's a consistency requirement both of quantum mechanics and quantum field theory.

QM:

The transition from state 1 to state 2 has an amplitude that is complex. Reversing time implies going from state 2 to 1 instead of 1 to 2, which requires complex conjugation.

Proof in QFT (I will just reproduce the formulas that you can't see in the video below, by Sidney Coleman, the images are awful-quality):

 

q(−t)=U†Tq(t)UT

 

 

p(−t)=U†Tp(t)UT=−p(t)

 

 

[q(0),p(0)]=i

 

 

U†T[q(0),p(0)]UT=i

 

 

[U†Tq(0)UT,U†Tp(0)UT]=i

 

 

[q(t),−p(t)]=i

 

 

[q(t),p(t)]=−i

 

Contradiction with canonical commutation rules. The intuitive argument that I've given you for QM is perhaps even more illuminating.

Sidney Coleman, Lectures on QFT (Harvard). Lecture 7; 2' 02''-11' 57'':

https://youtu.be/Y4W5qGbW-xg?list=PLhsb6tmzSpiwrZuDMyweABm7FShZu3YUv

Version in PDF:

http://fafnir.phyast.pitt.edu/py3765/Coleman-QFT.pdf

(there are two paradoxes if you define time inversion as a unitary operator; the other one is for the Hamiltonian)

Conclusion => Time inversion in QM or QFT must be implemented by an anti-unitary operator. Otherwise, you run into inconsistencies.

I don't know what you've read into Weinberg, but it's either he or you wrong. I'm guessing you.

Wrong again!! When you deal with a tiny particle in the presence of a black hole, you can write its Lagrangian and study its motion in the background geometry of the big object. How do you think one calculates the motion of Mercury and the anomalous precession of its perihelion? One completely ignores the distortion that Mercury itself produces. In that case, the proper time of the particle is a parameter to describe a geodesic in the background geometry. The proper time of the particles you're talking about is the parameter of a curve. Never mind that it's a "dimension". You really must study GR!!!

Im not sure I follow, as I have not studied QFT. Thank you for the formulas. I've watch that Sidney Coleman video and I understand that in his example, he is treating a time transformation as the reversal of a process. The question again, as I have stated before is, have we really observe something moving backwards in the time dimension? The answer is, no, that is why time transformations are defined anti-unitary arbitrarely. The only reason Weinberg rejects it being unitary, is the fact that it would imply negative energies.

I dont think that if you could reverse time in GR, a process would run blackwards. Time in GR is a dimension, "similar" to a spatial direction. I can move up or down, and say hello when going up, and say hello again going down, without having that process reversed. Im always talking about time transformations as moving in the other direction as usual in the time dimension, not reversing processes. If treated as a dimension, positive and negative time is not the difference between a process and the reverse process. I understand that if you are limited to positive time, then yes, it is related to the motion of a test particle in a gravitational system through geodesics as you said. But you cant reverse time in GR, since GR is built prohibiting those transformations. As we discussed before, I would have to extend GR for that.

Anyway, Markus pointed out that exotic matter cannot be explained by the Standard Model. I understand that considering time transformation unitary does not agree with QFT, although you can work out the math in the Dirac equation and in Lorentz transformations, and both agree on the result. Perhaps somebody could work out the math for QFT, but that is not going to be me.

Quote

You really must study analytical mechanics and some classical field theory. Forget GR for now. You need lots of basic formalism.

I know a bit of classical mechanics, I am a mechanical engineer.

40 minutes ago, MigL said:

A point I'd like to make, is that BHs grow regardless of your 'mechanism'

All BHs we know of are assumed to be the result of gravitational collapse, and as such, have a minimum size ( no evidence of primordial BHs ).
The 'temperature' of a BH is inversely dependent on its size; large BHs are very cold.
Even in the absence of any accretion, the BH temperature is much cooler than the CMB radiation, and as a result, will be a net absorber of radiation.
And grow in size.

Only when the universe approaches 'heat death' will 10 stellar mass BHs actually start to shrink due to radiation losses.

True, I already knew that.

44 minutes ago, Ghideon said:

How do you plan to get the information out? 

I realise I was not clear enough. By hidden from observation I mean:
A: Not possible to detect or observe from outside of the event horizon since the observable is bound the event horizon 
and
B: No mechanism for entering an then exiting or sending signals back from within a black hole is presented 

 

Alright, but that is another question!

You were arguing that the fact that I use negative energies which are hidden behind an event horizon looked suspicious.

If you let me make use of the example I talked about before, with virtual particles, these have indirect effects that can be observed (cassimir effect). With black holes and for no quantum approaches, the observables are very few: size (dependent of mass), spin, or charge. Curiously, one of these, when observed, does not match the prediction of GR when combined with accretion and merging estimations. One may argue that the estimations are wrong (MigL did), and interior model we use for black holes with GR is right, but supermassive black holes are way too big for our estimations to be wrong (the would be very, very, very wrong). Others have proposed eternal primordial black holes, and I propose my model. In my model, no information escapes the black hole, that is forbidden, but the event horizon grows, which is something that we know already happens by other mechanisms such as accretion. And it can be observed. Spin may also tell a lot about how black holes grew, but I have not study the consequences of my model for spin of black holes and actual observations (spin is difficult to estimate in supermassive black holes, because it can change due to the "sense" of the spin of accretion matter or other black holes that merge, and no body knows about the spin these had during the life of a supermassive black hole).

I dont know where do you want to go with this question, since we arrive at the same discussion we had earlier about whether if my model is the only one consistent just using GR, or that many others can be built whose predictions are the same, so even if my models' prediction matched actual observations, one would not be sure whether if my model is the one that is correct (your argument).

And who knows, as far as I know, hawking radiation is independent of what lies inside the black hole, but perhaps it depends somehow of it (it certainly changes the mechanism by which it reduces the mass of the black hole inside, since that implies a negative energy flux in words of Hawking, and in my model, they can only be negative energy fluxes inside the black hole), and my model would change that hawking radiation (for instance, maybe it implies that it does not exist), giving you another way to prove it. But this is speculation about my speculative model... Im just saying that I might be missing a better way to prove it myself.

2 minutes ago, Ghideon said:

I agree! 
I just have some (personal) problems when the mechanism in an explanation, be it negative energy or some other concept, is hidden in such a way that it is impossible to observe or detect even in principle. For instance hiding behind an event horizon but resulting in a black hole that from the outside will look the same as if modelled/predicted by an accepted theory. Such explanations gets too close to being unscientific for my taste, kind of like "God Did It", "God of the gaps" or "last thursdayism".

You can observe it, just go inside a black hole and perform an internal gravitational experiment. Im sorry that we dont have a black hole near us, but in principle yes, it is possible to go inside, so it is not hidden.

If it were non-observable, nor directly or indirectly, that would not be science (i guess it would be methaphysics).

Take for instance virtual particles again, you cannot observe them (perhaps because god made them to live very short lifes  ), but you may argue that they exist due to observable experiments such as the Cassimir effect.

47 minutes ago, joigus said:

Have you considered the possibility of, e.g., a BH that is ejected into an intergalactic void, and therefore experiments no accretion?

Hi joigus,

I dont understand what do you mean with BHs ejected into intergalactic void. I guess they exist, or they could exist. Sure there wont be accretion in that case. But my model of inflation at the inside does not need accretion, a black hole always has matter inside, the matter belonging to the original star that collapses (I assume Schwarzschild black holes, either macroscopic vacuum black holes or eternal black holes do not exist). So inflation would always take place, whether if it happens only because of the mass inside from the original star, or that one plus accretion plus black hole merging.

47 minutes ago, joigus said:

OK. So, in your model, do BH's radiate or not? You don't seem to have made up your mind about that.

I never said that they didnt. Im just saying that any eternal growth mechanism for black hole, even if it slows down in time, counteracts hawking radiation, because this one is very very small. I guess Hawking radiation occurs, although we are not 100% sure since we havent observe it.

47 minutes ago, joigus said:

Do you realise that time transformations in QM or QFT are always represented by anti-unitary operators? You propose a unitary T operator, which is inconsistent with how the quantum states represent time inversions: 

Yes, in other words, im redifyning what a time transformation is. Just like somebody did for the Dirac equation as I showed in other paper. The question is, ¿how do we know time transformations are anti-unitary? ¿Has somebody ever observe one? I believe not, you may have observed irreversible processes like: https://arxiv.org/pdf/1410.1742.pdf  which may break time process symmetry, but no time transformations where times goes backwards.

47 minutes ago, joigus said:

Or Weinberg's Quantum Field Theory, vol. 1, p. 128, eq. 3.3.44, which you cite in your pre-print.

Do you realise that one-particle states in QFT must have both "positive" and "negative" energies* if you want to preserve microcausality? The Dirac spinors that you obtain in the energy representation of the Dirac equation with either sign in,

 

e±i(Et−p⋅x)

 

are not one-particle states. The closest to the physical representation is the chiral one: https://en.wikipedia.org/wiki/Gamma_matrices#Weyl_(chiral)_basis

I dont know about QFT. I only know what Weinberg stated, that the only reason time was defined anti-unitary, is because if unitary, "for any state  of energy  there would be another state  of energy with negative energy". 

47 minutes ago, joigus said:

You seem to want to deal with these time inversions as some kind of active transformation (something you actually do to a particle) rather than a passive transformation (a simple re-labelling of parameters). How does one interpret this flip in the particle's time?

The only consequence this unitary time inversion has in the Dirac equation is that negative energies imply negative masses. If you agree the prediction of negative masses being repulsive between each other of GR, then the only physical change that a unitary time transformation does in a particle is that it changes to behave antigravitationally for other particles with negative energy and mass. (I might make a point here, which is that the time transformation in my model may also occur together with a parity transformation, because when you redefine time as unitary, Tp(T^-1)=p , so it also changes the usual parity transformation that a time transformation is linked to).

47 minutes ago, joigus said:

Why does the particle not experience its own past when it falls into the horizon?

Because that is not what time in GR is about. You may use time to reverse processes in particle physics, but time in GR is a dimension. As I said, in my model, a time transformation only switches to antigravitational interactions. A particle that has fallen into a black hole, cannot trace its own particles` past, because that would mean escape the black hole from inside, which is not possible, so that proposal in your question is inconsistent.

47 minutes ago, joigus said:

Does the particle's energy get inverted? If so, is energy not conserved at the horizon for the in-falling particles, going from E to -E and thus energy conservation being violated by an amount 2E?

You can easily check that what is conserved is the absolute value of energy. I believe that is what GR accounts for, absolute values of energy. I guess since exotic matter and negative energy densities have been studied in many fields of GR, even in models where they interact with positive energies, that jump does not violate energy conservation. QFT might be different, but since particles of E and -E never interact between each other in my model, the notion of E being twice -E is not relevant. There is no first I have E energy, then Zero energy, and finally -E energy, it has to be an instant switch.

47 minutes ago, joigus said:

Be aware that the fact that something has been published is no guarantee that the scientific community at large considers it correct, or even worth discussing.

I agree.

8 minutes ago, joigus said:

This is something I don't understand either. +1

Neither do I understand how a growing BH implies the non-existence of Hawking radiation. Why couldn't it grow and evaporate?

Hawking radiation is an shrinking mechanism, a very VERY slow one. If you propose a non-ending mechanism of growth (accretion and merging eventually end), this one would counteract hawking radiation. It not a remnant as described in the remnant solution to information paradox, but in my model, black holes do not evaporate, because they never stop growing, and at the end, there is always what you might call a remnant.

But really I havent worked out in my model whether the information paradox is solved. As you are saying below, we dont even know if hawking radiation actually occurs. This is something secondary for me.

Quote

I don't think negative energies are necessarily prohibited, as far as one provides a mechanism to explain why they're not observed in the universe. I don't see that either in the "proposal".

Oh yes, in my model, negative energies only appear under a time transformation, and time transformations only can occur at event horizons, because no body as ever seen a time transformation (the time transformation of the Lorentz group). Moreover, having negative energies in the same causal spacetime as positive ones, result in paradoxes, in which you could build perpetual motion machines. That is solved when you divide for negative and positive energy spacetimes by an event horizon, which switches from positive to negative.

14 minutes ago, Ghideon said:

While scanning for more information I found a paper with several similarities to your opening post and the concepts introduced. Emphasis mine:

Source: http://www.m-hikari.com/astp/astp2020/astp1-4-2020/p/uruenaASTP1-4-2020.pdf *

@muruep00 is the paper worth reading to get more details about your idea? 

To me at least, it looks like something very similar has been published?

 

 

Spotted an error, meant to say: I do not see how a solution using just GR can use quantum effects for support.

 

*) I have no opinion regarding the reputation of the publisher or the quality of the paper. 

 

Hi Ghideo,

First, Im happy that you are willing to do some research related to my idea. References of that paper are also interesting, if you want to go further.

Second, it is not difficult to guess that its my paper, since my username is my email address in it . I wrote that this idea was not published because I did not want to post my paper here, and I just wanted to comment on the ideas in a conceptual way. 

The quality of the paper is bad, and I have been re-writting it this summer, I think there are some things which demand a correction, and others can be better explained and further mathematically justified, that is why before sharing my idea here as a preprint, I want to finish it first. At the end (and now that my identity has been revealed), Im just a recent and young graduate in engineering, and my knowledge in modern physics is very limited (I study independently GR). As you pointed out, the publisher is not as good as one may want it to be, its a q4 journal, and I would like to publish in a better journal (just because I think my idea is worth it, I do not want to become a researcher).

7 minutes ago, joigus said:

Thank you very much, although you cut short @MigL's answer only to show what you want (he telling you that you're right about something). And now I quote Wikipedia:

https://en.wikipedia.org/wiki/Black_hole_information_paradox

I would have to go in more detail into what  @MigL was trying to tell you. Maybe he misunderstood you. I may have also misunderstood you, as it's very difficult to be sure what you're talking about (you never seem to get around to defining mathematically what you're saying). But further below he told you:

Anyway... The information paradox has nothing to do with macroscopic entropy, which is the item you seemed to be referring to. It has to do with microscopic entropy, which is just volume of phase space. There are two versions for it; one classical (Liouville's theorem), and another quantum mechanical (unitarity, although I don't like that term; it's clearer if you say "pure states into strict mixtures").

Microscopic entropy (phase space volume) is strictly conserved in physics.

Volume in phase space has two parts: One you can see by coarse graining (macroscopic) and another you can't see (total minus coarse-grained). The total is the one that concerns the paradox.

Of course BHs create lots of macroscopic entropy, but that's not the problem, nor is it a paradox. It's actually the common pattern in Nature.

What is a paradox is that BHs seem to require the violation of conservation of phase-space volume, which Leonard Susskind, e.g., calls "distinctions", because he is very careful about the concepts. Violation of the number of distinctions is not the same as irreversibility. Hossenfelder is also very careful to distinguish between what she calls "irreversibility" (it's actually non-conservation of distinctions) and violation of time-translation invariance.

I think Hossenfelder (in what clearly is a popular video, not a lecture) does a very good job of explaining a difficult concept, but unfortunately she uses the word "irreversibility" which has a long tradition in thermodynamics, and is to do with macroscopic entropy. Nevertheless, she superimposes a movie explaining what she means, and it becomes very clear she means conservation of distinctions: Liouville's theorem. This "irreversibility" (it should never be called that way, and I stick to Susskind's term "conservation of distinctions") is what seems to be violated in Hawking's argument.

If that's what your theory solves, well congratulations. I haven't seen a single formula yet proving that your "model" transforms pure states into pure states. Your insistence on time reversal only suggests to me that you keep confusing both (different) concepts, as explained by Hossenfelder.

In the classical version, this would imply that two different initial states:

 

q1,p1

 

 

q2,p2

 

merging into the same outgoing state:

 

q,p

 

Or the opposite (one trajectory splitting into two). That would also result in violation of Liouville's theorem. So "irreversibility" is an outstanding misnomer. It would be non-injective character in the evolution mapping, in either direction. I don't think that name will stick though.

In the QM version of such violation, a pure incoming state:

 

ρin=12(|ψ1〉+|ψ2〉)(〈ψ1|+〈ψ2|)=|φ〉〈φ|

 

comes out as a strict mixture:

 

ρout=12(|ψ1〉〈ψ1|+|ψ2〉〈ψ2|)

 

Now, it's not a matter of thermality, really. Thermality is not the crux of the matter. It can be added to the picture, it's probably there, but it only confuses things. It's rather a matter of one trajectory splitting into two, as Leonard Susskind very clearly explains in several lectures, available online.

That's probably why Hossenfelder doesn't like to characterize it in terms of information. "Information" seems to imply an observer. In this case it's Nature itself that's erasing its distinctions. You see? Susskind's word "distinctions" is what conceptually cuts it. And even better is using some maths, they leave little or no doubt about what you mean.

 

Thank you for that extensive explanation. 

I see what you wanted to point out, but I dont think MigL was referring to that.

My question is, if black holes do not evaporate, does the material entering a black hole (pure state) have to be transformed into the mixed state of hawking radiation, if this last one exists? Because my idea implies that a "remnant" always remains, probably with all the information, and that is one solution to the information paradox.

btw: my time transformation idea at the event horizon has nothing to do with this time reversal

2 hours ago, joigus said:

It's you who doesn't understand the information paradox. It has nothing to do with disappearance of macroscopic information. It's about volume of phase space (classical mechanical picture) or, in QM, violation of unitarity. It's about disappearance of microscopic distinctions. Irreversibility is not involved.

How would macroscopic irreversibility be at odds with the physics we know if it is a universal law of physics? Don't you have a grasp of basic thermodynamics?

How can you claim to have solved a problem you clearly don't understand?

I'm back.

Welcome back. I quote MigL regarding my explanation of black hole information paradox:

6 hours ago, MigL said:

My apologies. You are, of course, correct.

I just copied the explanation of the information paradox from Sabine Hossenfelder, you can check it here: 

Now, following with my idea again, and answering joigus, it is clear that if you propose a new mechanism of growth for black holes, no matter how slow it is after plenty of time (as long as I does not stop), evaporation does not take place, thus, solving black hole information paradox.

5 minutes ago, Ghideon said:

Your insisting of believing is not the most convincing scientific argument. You have not yet provided any arguments or attempts at experiments or observations that makes your "GR-only" solution stand out as correct. Where is the evidence that negative matter exists? How is negative matter allowed without supporting evidence while other alternatives are rejected? 

Well, there is already evidence for energy condition violations in the Cassimir effect and quantum fluctuations. Exotic matter may seem different, but it is just a name, technically is negative energy density, which is negative because it violates energy conditions. Additionally, other models rely on negative energies, such as Hawking radiation, I quote: "A renormalised operator which was regular at the horizon would have to violate the weak energy condition by having negative energy density" "This violation must, presumably, be caused by a flux of negative energy across the event horizon which balances the positive energy flux emitted to infinity" "it is shown that any renormalization of the energymomentum tensor with suitable properties must give a negative energy flow down the black hole and consequent decrease in the area of the event horizon. This negative energy flow is non-observable locally." Hawking even states that hey! this negative energy does not solve the singularity "Therefore one would not expect the negative energy density to cause a breakdown of the classical singularity theorems until the radius of curvature of space-time became 10" 33 cm" https://www.brainmaster.com/software/pubs/physics/Hawking Particle Creation.pdf

2 minutes ago, Ghideon said:

Ok, so if you have success with your simulation then we have a result based on mathematics rejected by the experts, supported by zero observations and requiring unobserved physical processes hidden from observation behind an event horizon. That leaves plenty of room to use other models that yours. 

If you were able to simulate it, its because math works out I guess..

What math is rejected by the experts in my idea? 

You may change "supported by zero observations" to "consistent with all available observations".

I again insist that I believe no other model using just GR can be built apart from mine (if so, I think I would have also came up with different possible versions of my proposal, which I havent)

25 minutes ago, Ghideon said:

If you are curious you can open a thread in the mainstream section and ask about supporting evidence for GR. 

You got me wrong, I trust GR, but not inside black holes. Let me change my question: Which supporting evidence does the nowadays model for the inside of black holes have that mine doesnt?

Quote

Established theories have limits. There are questions about cosmos that may not yet have a scientific answer. How does that make your idea correct? 

My idea tries to give a scientific answer to that question about supermassive black holes.

Quote

Your idea had interesting properties, that's why I chose to enter this discussion. May I suggest we focus on how you intend to back up your claims, rather than reiterating reasons for researching black holes? 

Yes, I though that I wouldnt have to remind people in this post that you can build a different model for the interior of black holes using just GR that does not contradict observations, so that it is reasonable to explore the idea.

Also, any suggestion to the idea are welcomed. I dont know as much about GR as some people in this post, so somebody might want to back up my claims.

What I think is that, if my model was simulated and it accurately explained supermassive black hole evolution with actual estimations, then it would be reasonable to think that mine is correct and (lets call it Markus' model) is not, because it cant predict supermassive black holes evolution and outside black holes, both are the same. If you could built different models without relying on magical phenomena of a theory of quantum gravity (as you discussed before), and my model was the only one consistent with observations and simulable, then you would have no alternative but to use mine.

14 minutes ago, MigL said:

Not by accretion, but if you localize enough mass/energy ( by primordial BHs, dark matter, direct collapse of gas clouds, or any other mechanism ) you can create as big a BH as you want.
So the problem is not BH 'growth', but having enough initial mass/energy to collapse into a supermassive BH.
And that IS related to galaxy formation.

That is because usually no body considers that perhaps, there are another mechanisms of black hole growth apart from accretion and merging.

Quote

I don't think you understand the information paradox...

"The black hole information paradox^[1] is a puzzle resulting from the combination of quantum mechanics and general relativity. Calculations suggest that physical information could permanently disappear in a black hole, allowing many physical states to devolve into the same state. This is controversial because it violates a core precept of modern physics—that in principle the value of a wave function of a physical system at one point in time should determine its value at any other time.^[2][3] A fundamental postulate of the Copenhagen interpretation of quantum mechanics is that complete information about a system is encoded in its wave function up to when the wave function collapses. The evolution of the wave function is determined by a unitary operator, and unitarity implies that information is conserved in the quantum sense."

From      https://en.wikipedia.org/wiki/Black_hole_information_paradox

Information is lost once behind an event horizon, even if there is no evaporation or Hawking radiation.
IOW, your 'conjecture is in the same boat, and needs quantum gravity to stay afloat.

That is not right, you dont understand the information paradox. The problem with information in black holes is that black hole evaporation is an irreversible process. You cant tell from the final state (evapored) what was the exact inital state. There is no problem in quantum mechanics with the fact that some information is hidden behind an event horizon. This hidden information has not "disappeared", it permanently disappears when black holes evaporates through random radiation.

Just to make it even more clear, the black hole information paradox was discovered right after Hawking showed that black holes should radiate in 1973. This problem did not exist before 1973, and black holes were already been studied. Indeed, one possible solution to the information paradox is to propose a model in which black holes do not evaporate, leaving remnants.

Quote

Several people already have.
You simply dismiss them with "That doesn't apply to my idea."
Take some time; go back and re-read.

If it doesnt it doesnt.

Quote

And you haven't exactly said 'WHAT' your proposal is.
Possibly to avoid 'pigeon-holing' yourself, so as to avoid the expected counter-arguments.

A time dependent solution where the inflation due to the exotic matter inside grows the exterior event horizon.

22 minutes ago, MigL said:

GR certainly does predict the mass of supermassive BHs.
There is no upper limit on BH size/mass.
We don't yet understand the localization of large amounts of mass/energy in the early universe to account for them.
But again, that is a problem with galaxy formation; you have it backwards.

Well, yes, there is an upper limit, because eventually a very big black hole is no longer able to gain mass by accretion.

It is not proved that it is a problem of our estimations in galaxy formation. The orders of magnitude of supermassive black holes are much bigger than what you would expect, even in the worst case, for localizations of large amounts of mass/energy in the early universe. If that observation was so simple to explain with reasonable amounts of dust/stars collapsing in the early universe, then no other alternatives (such as primordial black holes) would have be studied. Well, the problem exactly is that those supermassive black holes formed very quickly in the early universe, that is the issue.

Quote

Pray tell. How does your model cope with the information paradox ?

If you take into account another mechanism of growth that does not eventually stop, no matter how small it is (because hawking radiation is very, very small), black hole evaporation may not take place (this has to be proved, but it is trivial). With no black hole evaporation, there is no information paradox.

Quote

Why can you easily 'see' problems with BHs as defined by GR, or as defined by Ghideon in his demonstrative thought experiment, but you are totally oblivious to the problems in your conjecture ?

Show them to me, clearly. I already asked you this question and you just answered that Markus stated that the overall metric must remain continuous and differentiable everywhere at the boundary and that the new metric must itself be a valid solution to the field equations. I dont think my idea violates any, and Markus was arguing against a Schwarzschild exterior solution to my proposal, but my proposal is not Schwarzschild, because its time dependent. Joigus also pointed out that justifing that time transformations switch to negative masses in the Dirac formalism is not enough, and I should also prove that in QFT. I answered that as long as that transformation is consistent in the Lorentz group for GR, and it changes the sign of masses, that is all you need for building a model in GR. Guideon stated that different models can be proposed, which give the same prediction as mine, so that even if my model predicted supermassive black holes correctly, my model may not be correct. I pointed out that I believe my model is the only consistent one you can build without invoking the effects of an unknown quantum theory of gravity.

4 minutes ago, Ghideon said:

When may we see some supporting evidence?

Which supporting evidence does the nowadays model have that mine doesnt?

Quote

At this time Markus model, within the known limits where it is applicable, predicts things verified by observations better than other alternatives. It is not so much about belief. Rather about review of information as it is made publicly available, making choices based on experience and education and/or with help from others with expert knowledge.

It most certainly does not predict the mass of supermassive black holes we observe. And there are more troubles with it, such as the information paradox.

12 minutes ago, Ghideon said:

Where did I say that my addition to GR is a quantum theory of gravity? I said an expert may argue that my idea is not compatible with quantum mechanics*. Note that I play by the rules you set. You ignore Markus and other experts and you present no supporting experiments or observations. I do the same.

You suggest in you idea that somehow, regular matter appears inside the black hole. There is no known mechanism to do that, the only way to propose that is to invoke an unknown theory of quantum gravity. My model does not require to mention quantum gravity at all!

Quote

Thanks. You have successfully observed that my intentionally flawed idea differs from your idea. Now back to the question I try to get answers for, slightly modified: 

What observations or experiments supports your idea while falsifying my idea*? 

Perhaps none. May I also change my question?: Why did anybody build a different black hole interior just using GR, that would fit better the observations? Why stick to Markus model as a belief if other models can be built?

Quote

That I believe in your model is a good start. Can you present any convincing arguments why others should find the model plausible? 

It is about the physics we already know, it does not create paradoxes, it solves some theoretical problems in an elegant way (like the runaway motion, interior of kerr black holes), it may fit better the observations we've got...

6 minutes ago, joigus said:

It serves me well for trying to be intuitive. I didn't mean physically going. I meant transformations and mappings.

May I point out that you haven't shown your "model" yet? You really have no model, do you?

Your transformation? You have defined no transformation. I've got a purple one-eyed winged elephant. Do you want me to talk about it? I bet I can google for something resembling it and come up with some links to keep this going.

At this point, I take my leave.

The transformation is an antichronous transformation, everybody already know these. It might not have been worked out in QFT, but it has been in the Dirac formalism. Anyway, this is not necessary, at end, im just dealing with GR and Lorentz transformations.

11 minutes ago, joigus said:

It's the opposite. First order effects cannot be detected. Second order ones can. Those are called tidal forces. If a small BH went through you, you would notice, believe me. But if it were you who's small in comparison to a quiet silent BH, you would notice nothing remarkable when going through the event horizon.

Einstein's EP is the essence of gravity. How could it exclude gravitational effects? Markus has told you that too. You seem to be just insisting on what we know not to be true.

Einsteins equivalence principle: The outcome of any local non-gravitational experiment in a freely falling laboratory is independent of the velocity of the laboratory and its location in spacetime.

A local gravitational experiment could be an internal gravitational experiment, the only way by which you could verify that gravity has become repulsive in you local spacetime.

Quote

Continuity, differentiability and injective mappings are very important in GR. In fact it's a paragon of these features. Intrinsic to its very foundations. Basically, whenever something takes you from A to B, it must be possible to reconstruct the going from B to A. Otherwise it's a can of worms you're opening. It's up for grabs for any ad hoc thinking basically.

You cannot go from A to B and from B to A when you go into a black hole (my transformation can never take place from antigravitational to gravitational, or in time transformation, from negative time to positive time).

11 minutes ago, joigus said:

You see? This is the problem. This is what I meant when I said:

(Point number 1.)

Then I must say I have an unfinished idea (which is true, if not, I would publish) and I would ask in this forum about ways to justify it by the generalization of GR we talked about before. But I can still ask if my idea, with the hypothesis, could work or not. I mean, what is an hypothesis if it is not a "my theory could be valid if..."? It cant be a crackpot idea just because of that, if Im not finished developing that.

2 minutes ago, joigus said:

The Lorentz group splits into 4 chunks. Only one of them is connected to the identity, the so-called proper ortochronous. The other pieces are not even groups and you cannot continuously go from one to another. It's as if they lived each in their own island.

This is explained in the paper we were talking about. I have found others dealing with this topic: https://www.researchgate.net/publication/226329889_Antiparticles_from_special_Relativity_with_ortho-chronous_and_antichronous_Lorentz_transformations

What is the problem of having non-continious transformations?

2 minutes ago, joigus said:

The only solution I see for defining time inversions and/or changes in the metric is to extend the number of dimensions and try to figure out what the Einstein equations are as a projection from that richer space. Maybe in that higher-dimensional space the transformations that you're envisioning do make sense as a connected group of transformations.

I dont think higher dimensions are requiered. To my knowledge, the existence of time transformations were only ruled out because no one observed them, and so, they were said to be unphysical. 

2 minutes ago, joigus said:

Next step would be to make your assumptions as clear as possible. Formulate a plausible set of approximations to draw clear mathematical conclusions. They don't have to be numerical. They could be qualitative.

What are qualitative approximations?

2 minutes ago, joigus said:

As to time stopping, pay heed to what Markus told you. That's very very likely just an artifact of the coordinates. That's what it looks to be. They only well-referred unambiguous observers in GR (IMO, there could be differences of opinion here) are free-falling ones. And when you change coordinates to locally minkowskian (free falling observer) the weird "inversion" (which is actually a swap radius <--> time) disappears. If the BH is big enough, the observer feels nothing. That's what the maths say.

I will keep studying this to check if their is a way to justify my idea. I want to point out that free falling observer should feel nothing due to the Einsteins equivalence principle, but this excludes gravitational effects. That means, if there was a gravity related change at the event horizon (for instance, gravity swithching to antigravity), one could realise that by an internal gravitational experiment for instance, but those are not restricted by the Einsteins equivalence principle (they are for the strong equivalence principle, but E.e.p. is enough to build GR).

2 minutes ago, joigus said:

As to wiping out the singularity, Ghideon has pointed to the possibility of alternative heuristic toy models, Markus has told you about torsion or going to the more realistic Kerr metric. I would like to mention also that, if the BH is of stellar origin, there may be what remains from the dead star playing a part there.

Yes, Ghideon is right, but Im trying to justify my idea without relying on an unknown quantum theory of gravity, and my model is the only one I find plausible. Einstein-Cartan theory may be true, but Markus itself pointed out that it is in contradiction with observations (I dont know which, I dont know much about Einstein Cartan theory). Im trying to build my model so that it does not contradict any observation. And yes, I account for what is left of the dead star in my model, which crosses the growing event horizon and transforms into the exotic matter I propose.

2 minutes ago, joigus said:

The only serious alternative I can see for what you want to do is to generalize GR. That's quite a challenge.

And that's about what I can think of right now. I'm trying to be as helpful and constructive as possible.

Thank you very much, I will keep developing my ideas with you suggestions

17 minutes ago, joigus said:

You forgot to read the abstract:

Relativistic quantum mechanics is a play-toy. If you want to get serious you need to use QFT. When you do that, first thing that happens is that Dirac 4-spinors go in the rubbish bin, because they're not irreducible representations of the Poincaré group (particles). That's one of the reasons why the SM is formulated in terms of Weyl spinors. The authors don't say to be proposing any plausible mechanism or making any strong claim. They seem to me to be arguing that negative energies are not as crazy as it may seem if you use a unitary CT operator that they introduce in the naive wave function formalism. That's all. You've read too much into it.

I can accept that. The paper also states and shows that it is in agreement with Lorentz transformations and allowing the antichronous ones (which is what I really care about in my proposal). What are you thoughts about these?

Quote

No. That's not a Wick rotation. What Hilbert did there was to absorb the minus sign in the metric by re-defining time as pure imaginary. I suppose Hilbert was much more familiar with Kronecker deltas than Minkowski pseudometrics. That's kind of a re-labelling, a convention rather than a transformation. I don't know if I'm explaining myself: You take the sign from the metric and absorb it into the time definition. That's why I asked you about the changes both in the metric and in the coordinates. Nothing sacred about the metric coefficients in relativity, but the contraction of metric with coordinate differentials is next-to-sacred. And there are good reasons for it.

A Wick's rotation is very different. The metric doesn't change, but time does. This is called a Euclidean-time calculation. You calculate the partition function, pretend time is imaginary, and obtain a nicely convergent result, from which you guess the actual solution by arguments of analytic continuation. You're not swapping the sign from one place to the other; you're actually changing it, obtaining a "fake" solution, and guessing the physical one.

You're keeping your ideas behind a horizon in many senses. I suspect it's all because you don't want anybody to really see them. It's all like behind a thin veil of heuristic censorship (GR joke.)

I certainly don't want to go through the same ordeal as other brave warriors, getting fired from behind the bunker of a conceptual horizon. I'm just trying to give them a temporary relief in battle. 

Thank you for your explanation, you seem to know much more than I do in this topic. What if you build GR allowing the antichronous transformations? Wouldnt it be reasonable that the place where they take place is the event horizon? (my motivations for this are complexity of time treatment as you explained, the fact that the signature of the metric changes, the fact that time seems to stop at the event horizon for an external observer). Unfortunately no body has extended GR allowing these transformations to take place, but it seems reasonable to support my hypothesis of a time transformation taking place at the event horizon.

11 hours ago, joigus said:

I will add some points to what Markus, MigL and Ghideon have already said.

You talk about violation of energy conditions. What energy conditions? From what I know about energy conditions, they are imposed on the matter tensor; and there is no matter tensor in the Schwarzschild problem, as there is no RHS of Einstein's equations. It's a vacuum solution.

The energy conditions exotic matter violates. Im not proposing a new Schwarzschild solution since my idea relies on a non-static solution

Quote

You talk about quantum jumps at the horizon as possible justification for your jumps in the metric. Do you realize that you're talking about quantum gravity?

Yes, but there is already a mechanism that we know in relativistic particle physics that does the same job: a time transformation (https://arxiv.org/abs/1809.05046). Does it imply that the jump in the metric is not smooth or not differentiable? I dont think so.

Quote

You seem to suggest a Wick rotation. Can I see a mathematical formula? How does it act on the metric coefficients and the coordinates? You've been very ambiguous about this. Is it a Wick rotation or an time inversion? Those are different things.

A wick rotation is what Hilbert did to Schwarzschild approach to his metric (https://www.jp-petit.org/Hilbert-1916-de.pdf page 60 above eq. 45). I always stated that I propose a time transformation. Schwarzschild treated time as real coordinate, and Hilbert as an imaginary one. Thats why I dont trust Hilberts metric (which is the one used nowadays). But this was in the discussion we had in which I asked Markus about the possibility of justifing a time transformation in the original Schwarzschild metric. The fact that Hilbert treated time in different way, and that the signature of the metric changes, were my motivations.

Quote

And may I ask what has been suggested to you before?:

What are your predictions?

Yes, my predictions is that black holes grow because of an inflation that takes places inside, not only by accretion and black hole mergers. Since we observe black holes "too big" for our estimations, It might solve that problem and at the same time, be the way to prove my model.

2 hours ago, Ghideon said:

Ok, since getting a straight answer seems not possible at this point I'll illustrate the issue with an example*.

Let’s identify the rules as I understand them from your earlier posts:
-What lays beyond the event horizon of a black hole can’t be directly observed (I agree on that)
-Beyond the event horizon we are free to assume the existence of things that according to current consensus may be considered unphysical in space outside the event horizon. For instance negative gravity or negative energy.
-The mathematics model running the simulation does not have to agree with consensus of relativity experts; Markus objections have not had an effect on your stance so far. 

I think the math can be worked out. In fact, Im trying to do it myself. There is no quantum gravity, its all GR. Again, Markus only stated that a time dependent solution is very complex (approximated models can be built), and that the solution has to be smooth and differentiable at the horizon, which does not contradict my hypothesis.

Quote

Singularity:
Make a simulation that cuts off the compression of matter inside the black hole at some very high density. That avoids a singularity and will, from the outside, result in a black hole matching observations. Markus, Mordred and other experts would object against my mathematics and my lack of compatibility with GR (and QM). I say they can’t observe what’s inside the black hole and I have no singularity, similar to your argumentation.

How does that cut off work? Isnt that just what people expect from quantum gravity? You need to specify what does counteract the gravitational pull at those high densitites.

Quote

As for the growing event horizon, inflation of the black hole or apparent increase of mass:
I could modify the model of the vacuum inside the event horizon. Allowing regular matter to be created in some circumstances, adding mass to the black hole. Don’t worry about conservation of energy, we are inside the event horizon and I may propose such quantum fluctuations as per your argumentation. 

The problem is the regular matter you introduce to be created inside the black hole. Where does that regular matter come from? That makes no sense, since all matter in my model is very clear where does it come from, and Markus argued against solutions in which the vacuum is different inside and outside (which my model does not imply).

Quote

Result: By using your approach towards observations and falsifying I have pulled some examples out of thin air and ended up with something that seems to match your model’s predictions and current observations. My example ideas do not rely on negative mass, negative energy so they are simpler and more plausible. I have, as you did, ignored input from experts regarding flaws in my application of mathematics.  

The problem is: Can that model of yours be simulated? I guess not, since it relys in QM gravity. And I dont think its simpler, you just avoid explaining how do you counteract gravity inside.

Quote

Do you get the point? Can you show how we could tell that your idea is correct? Not just against my illustrations, but against such ideas in general. There must be something that makes your idea to stand out, allowing it to be confirmed or falsified. My point is that the level of explanations you have provided so far is not enough to support the claims you make.

I get your point: you can make similar but different models that would mimic the prediction of my model, so even if simulated and matching observations, it could be other model different than mine.

Well, true. But my model is the one that does not rely in quantum gravity (or magically appearence of regular matter). It is about things we already know! If you invoke quantum gravity, since we dont know how it works, any model can be built that would fit observations, assuming quantum gravity effects are one way or another.