Markus Hanke

A recent problem with that has been the advent of AI - cranks can now produce maths that look, on the surface, genuine and bona-fide, though of course once you look closely at it, it generally falls apart rather quickly. Likewise, one can start with a desired result (eg aforementioned orbit), and get AI to generate maths from a crank idea that on the surface appears to produce said result. All in all, it has become more labour intensive to debunk woo because of this.

I actually have that same issue - wanted to change my display name, but was unable to contact admin (my message wasn’t read). Any suggestions?

I think this was badly formulated on my part, apologies. What I meant was really that, when talking about conservation laws, the energy content of the gravitational field itself must be taken into account. This energy content is unfortunately not by itself a covariant quantity. At the same time, the covariant divergence also introduces curvature-related terms (as you correctly pointed out), which, when taken in isolation, are also not covariant. The only way around this is to introduce a new quantity that accounts for both energy-momentum of sources, and the energy content of gravity itself - it is only that particular combination that can be said to be conserved. This can be done, but I don’t know if this construction is unique.

You won’t ever see one, at least not within the domain of Newtonian and SR physics. There are fundamental reasons why this conservation must hold. In GR however, the situation is a little more subtle, as in regions of substantially curved spacetime there is no simple “law of energy conservation”. It’s possible to still formulate something along these lines, but one has to account for the self-interaction of gravity.

“Rate of time” is a meaningless concept. This is a discussion forum. If you don’t wish to debate your personal theory, then you have no valid reason for being here. While some things certainly can be expressed in terms of a single quantity like eg the gamma factor (not “rate of time”), gravity is an explicit counterexample - you need at least a rank-2 tensor field to correctly capture its dynamics. And since gravity is the dominating factor on large scales, this has a bearing on cosmology too.

You are right, people don’t understand the concept, and most are too shy and reluctant to approach me and ask. At one point in history, there were also some Christian monastic orders who lived based on alms mendicancy, but I don’t think they exist anymore, so people are no longer familiar with the archetype. But just to be clear - we don’t accept money (only food and material necessities), and we never approach people ourselves asking for stuff. We basically just stand there silently, hoping someone will come up to us. We have very strict rules of behaviour and conduct around the whole thing.

Just wanted to throw to other points into this discussion, which I think are pertinent: What do we actually mean when we use the term ‘poverty’; and Wealth is not necessarily the same as well-being. Of course, citizens need to have their basic needs met first; but beyond that, a society that is wealthy on paper may still not enjoy a high level of general well-being. This discussion shouldn’t just revolve around money.

I must admit I haven’t heard of this. Could you briefly explain the basic distinction here?

Exactly.

I think it's worth looking at this phenomenon a little more closely. In general, an antenna's dipole field is mainly made up of terms like \[e^{i(kr-\omega t)}\] But in the near field, there are also extra terms involving powers of \(\frac{1}{kr}\). Thus, the total phase of the field isn't just \(kr-\omega t\). Now, the velocity of the phase fronts (!) in the near field regime next to the antenna is \[v_{\phi}=\frac{\omega}{d\phi/dr}\] which can exceed c. It can, in fact, become arbitrarily large. This is quite a common phenomenon in areas like X-ray spectroscopy, quantum tunneling (see Hartmann effect), radio wave guides etc. It's often called evanescence in the literature. The important point to understand is that the phase velocity of the near field is not the same as the signal velocity of the overall EM field - the superluminal phase velocities are just a mathematical property of the field's phase structure, but you cannot use this to transmit any kind of information, and the Poynting vector (net energy flow) associated with these phases is zero. If you start to modulate the current in the antenna, then this disturbance propagates outward at c, and a new near field configuration is established as a result. This is entirely consistent with SR, which forbids superluminal propagation of causal influences, but not superluminal phase velocities. The situation is analogous to gravity - stationary fields act instantaneously even though they are spatially extended, but changes in gravity propagate at c.

I think this is just meant as a rough schematic. But regardless, top and bottom quarks don’t contribute to ordinary stable nucleons, as all their bound states are highly unstable.

No. Thus has already been explained multiple times now - yes, the experimental setup shows an apparent superluminal speed, but what is measured here is the phase velocity of the entire packet due to anomalous dispersion, not signal velocity of individual waves in a medium. There is no upper limit to phase velocity, and you can’t use this to transmit information. This is a well known phenomenon in the literature (often called “evanescent waves”), and is perfectly compatible with Maxwellian EM, which is Lorentz invariant. See here for example: PubMedOn the apparent superluminality of evanescent waves - PubMedThere have been many recent theoretical and experimental reports on the propagation of light pulses at speeds exceeding the speed of light in vacuum $c$ within media with anomalous dispersion, either

An important topic indeed I would just like to add here that “emergent gravity” is a term from existent literature, I merely used it since it seems to fit with the research program in question. I don’t agree with this. For example, one wouldn’t expect to see emergence in a simple harmonic oscillator; but if you had eg a very large ensemble of double pendulums all somehow influencing one another, it might be a different story. I think the complexity of the systems plays a role, and perhaps also the types of dynamics within it (linear? Non-linear? Chaotic?). Of course these terms need to be made precise. I think we must carefully distinguish weak from strong emergence here. There are no known examples of strong emergence, but plenty of examples of weak emergence - also gravity would fall into this latter category.

Hm, this is also a tough issue…I have never myself been in one of those “Emergency Accomodation” units, but I have heard accounts from homeless people who say that conditions in many of those places are deplorable, to the point that they feel safer sleeping outside. Depends what kind of “monk” you mean, specifically. In my particular case, our entire tradition is based on alms mendicancy, meaning we live exclusively on material donations freely given by others. We do not use, receive or own money in any form. So we stand outside this system. But perhaps this might be interesting in the context of this thread: we keep up the tradition of going on “alms round”, meaning a few times a week we walk into town with our alms bowls in the hope of receiving some form of edibles for our (one and only) daily meal. In my experience here in the West, and purely statistically: out of every 100 people I encounter, 96 simply ignore me and walk past; 2 are curious and ask questions, but don’t give anything; 1 will be actively critical, on rare occasions even hostile; and 1 will actually donate food. The same exercise done in a SE Asian country might yield a very different result. In my experience there are also differences between traditionally catholic and Protestant areas, even within the same country. So, culture does play a role in this question also. PS. Here’s another interesting observation I’ve made - those who are evidently well to do (ie arrive in expensive cars, have fancy clothes, watches etc) almost never give anything. On the other hand, I’ve gotten alms from rough sleepers on occasion. Go figure.

Good question. For one thing, all current systems that I know of have at least some qualifying conditions before a given individual is in fact covered by it. For example, I am based in the EU, and while I can freely move to any other EU country if I feel like it anytime I want, that does NOT mean that I automatically become resident there and get access to the social welfare system in that country - that's linked to certain conditions, which sometimes can be quite difficult to fullfil, even if you're there legally. Right now I am having that precise issue - I am legally resident in a certain EU country, but due to my rather unusual personal circumstances have not managed to gain access to the social security system here, because I don't fit into any of the usual categories of that system. So what I am trying to say is that there will always be people who fall through the cracks for one reason or another. More fundamentally, when it really comes down to it, altruism is a broad spectrum ranging from those who actively work at helping others in need, to those who are in it for themselves only. Most participants of any given system (ie those who elect the decision makers) will be somewhere in between those extremes. To ensure that no one falls through the cracks, the only viable solution would be some form of unconditional income that everyone gets, regardless of their personal circumstance, and without qualifying conditions ("universal basic income"). Even then, there's always going to be a small number who fail to manage themselves regardless. So this is a difficult problem. The only other option I could think of is to physically remove people from circumstances that are deemed detrimental to them, if necessary against their own will - not a good way to go, for obvious reasons that hopefully I don't need to explain. Note that the idea of a UBI has been trialled in places, but there seems to be no widespread political will or broad enough public support to implement such a system. Perhaps also it simply isn't possible to make it work in practice, I don't know (I'm no expert on this).

Yes, I would tend to agree. There are, however, topological QFTs that seem to capture some aspects of the Standard Model via topology (as opposed to geometry) of spacetime. To be clear, none of the fundamental interactions as we know them now can be fully described by pure TQFTs, as all of them contain local propagating degrees of freedom (ie moving particles). But still, there are intriguing connections here.

And that is a very valid concern! I appreciate you pointing it out. My main problem is, and always has been, that I’m just an amateur - I haven’t gone into the same amount of depth as someone who has formally studied those things, so there’s always the possibility that I’m missing something. That’s why it’s important to get reality checks from professionals like yourself Well, the proof is always in the pudding, meaning in whether the chosen approach fits observational data or not. Fact is that we have no evidence or indication of extra dimensions, microscopic or otherwise, much less of the extra required scalar field. Also, AFAIK some of the actual predictions that KK theory makes are different from those of QFT, and thus wrong - the Wiki article mentions the electron mass for example. So we can say that these two approaches to modelling EM are not equivalent, and that QFT fits the data much better. I guess this is why we don’t hear so often about KK theory - interesting attempt, but QED works better

It’s a unification of EM and GR, but it’s purely classical - EM appears when you add an extra spatial dimension to spacetime, which is curled up into a tiny circle, plus a scalar field and some more technical assumptions. As being classical, the model has no concept of field quanta. Can you specify what you mean by compatible with QFT? Kaluza-Klein is explicitly classical.

Yes, very valid point +1 I did not mean to make the thread above sound like the last words have been spoken on these matters...it's just that the connection between gravity and thermodynamics seems to be too strong to be a mere coincidence. And thermodynamics is "emergent" in the sense that it is a statistical macroscopic description of systems made up of microscopic constituents (or states). Lol, I do occasionally teach in real life (it's part of the "job" of being a monk), but of course that's not related to science. In general, I find it easier to explain things in writing than "live" in front of an audience.

What theories are you referring to, and what do you mean by “echo”?

That’s a very good point actually, I never looked at it from this angle before. It really is uncanny how few equations describe a very large set of seemingly different physical scenarios.

At the point where you leave the regime where the semi-classical approximation works well enough, ie at the point where you can no longer meaningfully average over things statistically, and the metric of spacetime itself ought to reflect the quantum properties of the source. This happens either at very low energies (single particles, or very small assemblies of particles), or at very high energies. Here we require full quantum gravity. But the problem is - if this entire research program with emergent gravity turns out to have some truth, then the concept of “quantizing GR” really doesn’t make much sense anymore (not that superpositions of metrics etc ever did make much sense to begin with). I am, at this point, really not clear about how meaningful the entire concept of “spacetime” even is in the quantum gravity regime, at least not in its familiar classical form. As I keep saying, I think new and deeper structures will ultimately be needed. PS. If gravity is a phenomenon of statistical emergence on larger scales, then there is also the possibility that the very notion of “quantum gravity” is simply meaningless. Consider an ocean with waves on its surface. The “water” on those scales is, microscopically, just an ensemble of molecules that obey the laws of fluid dynamics. But does it make sense to ask “where are the waves on a molecular level, and how do they function”? No. The notion is not meaningful, just as a single molecule isn’t “wet”. Likewise, perhaps the very notion of gravity isn’t meaningful at all on quantum scales, but only a statistical description of large scale systems. Just a thought.

Yes, very valid point +1 I did not mean to make the thread above sound like the last words have been spoken on these matters...it's just that the connection between gravity and thermodynamics seems to be too strong to be a mere coincidence. And thermodynamics is "emergent" in the sense that it is a statistical macroscopic description of systems made up of microscopic constituents (or states).

In the same sense that eg the Navier-Stokes equations are “emergent” from the statistics of particulate fluids and gases. The broader picture here is that, every time you start with QFT in general spacetimes with as-yet unconstrained metric, and add in the concepts of relative entropy plus some more technical tools (modular theory), the Einstein equations arise as consistency conditions. This is the same as, when you start with general particle ensembles and add in Newtonian forces and conservation principles, the emergent global “statistics” of these fluids are shown to obey Navier-Stokes. It that sense, NS is emergent. Same with gravity - the interplay of quantum fields and their relative entropies is consistent if and only if the background spacetime has a particular geometry that fits the configuration of quantum fields in question. Exactly. NB. The consistency conditions always turn out to be ordinary Einsteinian GR, not any of the many proposed alternatives or modifications.

The derivation obtains the semi-classical Einstein equations. The term "semi-classical" in this context means that matter fields (more generally: energy-momentum) are treated quantum mechanically, while the geometry of spacetime remains classical. Basically, they start with quantum fields, and show how classical spacetime curvature follows from them via the notion of relative entropy, plus some technical assumptions. They don't quantize spacetime geometry itself. The bridge between the two is given by the Bekenstein-Hawking entropy law, which is assumed in the derivation. That latter point is where I am somewhat confused though - the Bekenstein-Hawking law is itself a semi-classical result of QFT and GR, so pre-assuming it basically guarantees that you get from QFT to the Einstein equations. Thus, while an important technical result, the whole thing seems just a little bit like a tautology to me. But then again, maybe I am missing something, which is quite possible since QFT isn't my area of expertise. But my main point stands regardless - the very fact that one can associate thermodynamic entropy with certain types of horizons, while remaining fully consistent with both GR and QFT, indicates to me that gravity is quite possibly not a fundamental thing, but an emergent phenomenon, and this paper strengthens that position. Also, BH horizons having entropy at all seems to imply that the spacetime in the region enclosed by the horizon needs to have some sort of structure or microstates, and can't be smooth and trivial everywhere, or else the very notion of "entropy" associated with them wouldn't make sense. Just my two cents. PS. It is worth mentioning that the "relative entropy" referred to here is not standard classical thermodynamic entropy. It is something called Araki-Uhlmann relative entropy, and if I understand this concept correctly (I may not), it essentially measures how different an excited state of a quantum field is relative to the field's vacuum state.