Duda Jarek
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Exactly, GRW is perfect e.g. for human wandering through the web, indeed performing local randomly looking decisions. MERW for electrons  having extremely complex EM&wavebased dynamics, expressing our limited knowledge through its entropy maximization, with Andersonlike localization property e.g. preventing semiconductor from being a conductor, like in below electron densities from STM (scanning tunneling microscope) from http://www.phy.bme.hu/~zarand/LokalizacioWeb/Yazdani.pdf The big question is what to choose between, like for this molecular dynamics? Practical difference is that only MERW has QMlike localization property  do we observe this kind of effects for molecules? Like entropic boundary avoidance, e.g. for [0,1] range GRW/diffusion/chaos would predict nearly uniform rho=1 stationary distribution, while QM/MERW predicts rho~sin^2 distribution avoiding boundaries  do we observe it for molecules?

Thanks, my general thoughts is that: GRW should be used when the walker directly uses the assumed random walk, like "drunken sailor" throwing a dice in each node, or just human making looking random local decisions which link to click at for https://en.wikipedia.org/wiki/PageRank  it is for walkers performing nearly random decisions accordingly to local situation, having characteristic length like one web link. MERW stochastic propagator is nonlocal  depends on the entire space (in eigenequation of adjacency matrix)  it shouldn't be seen as directly used by the walker. Instead, this is thermodynamical picture  the safest (entropy maximizing) assumption we can make for limited knowledge situations like some complex hidden dynamics e.g. in electron conductance.

To choose random walk on a graph, it seems natural to to assume that the walker jumps using each possible edge with the same probability (1/degree)  such GRW (generic random walk) maximizes entropy locally (for each step). Discretizing continuous space and taking infinitesimal limit we get various used diffusion models. However, looking at mean entropy production: averaged over stationary probability distribution of nodes, its maximization leads to usually a bit different MERW: https://en.wikipedia.org/wiki/Maximal_entropy_random_walk It brings a crucial question which philosophy should we choose for various applications  I would like to discuss. GRW  uses approximation of (Jaynes) https://en.wikipedia.org/wiki/Principle_of_maximum_entropy  has no localization property (nearly uniform stationary probability distribution),  has characteristic length of one step  this way e.g. depends on chosen discretization of a continuous system. MERW  is the one maximizing mean entropy, "most random among random walks",  has strong localization property  stationary probability distribution exactly as quantum ground state,  is limit of characteristic step to infinity  is discretization independent. Simulator of both for electron conductance: https://demonstrations.wolfram.com/ElectronConductanceModelsUsingMaximalEntropyRandomWalks/ Diagram with example of evolution and stationary denstity, also some formulas (MERW uses dominant eigenvalue):

Where is deuterium and tritium found?
Duda Jarek replied to Xian's topic in Modern and Theoretical Physics
I have seen some papers that tritium is also found in volcanoes, suggest ongoing nuclear reactions (halflife ~12 years to to He3) https://www.sciencedirect.com/science/article/abs/pii/S0377027399001778 It brings interesting question of He3/He4 ratio in Earth mantle, e.g. http://www.mantleplumes.org/HeliumFundamentals.html Generally there is problem with He3 sources required for many application like ultracooling or lung imaging, especially after 911 as a lot of it was needed for neutron detectors for airport security. I have heard that its important source was decay of tritium in thermonuclear warheads and in some moment Russia has stopped selling ... 
Could signal encryption explain the Fermi Paradox?
Duda Jarek replied to TakenItSeriously's topic in Astronomy and Cosmology
Even deducing compression might be extremely tough, starting with question if it uses Huffman, arithmetic or ANS coding, for what probabilities ... deducing video compression from signal alone seems impossible task. 
Thought experiment: how would physics develop without Einstein?
Duda Jarek replied to Duda Jarek's topic in Physics
Observational effects of strong magnetic fields are e.g. jets  are saying that their presence excludes possibility of black hole? I don't know  there are theoretized Kerr's black holes and I think they have magnetic field, also from acreting matter: https://en.wikipedia.org/wiki/Rotating_black_hole ? And the question is for the other side: imagine civilization without Einstein  developing low field corrections: succeeding terms of Taylor expansion of GR, not being aware that they should sum up to GR. Having QFT, they see renormalizability as crucial  how to convince them that nonrenormalizable GR is the only way? For this purpose we need observational effect of black hole  convincing that it definitely isn't just a heavy neutron star, maybe using event horizon. Maybe Hawking radiation? How far are we from its direct observation? 45 replies

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Thought experiment: how would physics develop without Einstein?
Duda Jarek replied to Duda Jarek's topic in Physics
Without Einstein (situation this thread was supposed to be focused on) we would add corrections to Newton  first terms of Taylor expansion of GR ... mathematically getting agreement of low field effects. I have a feeling that you don't believe in Taylor expansion, Fermat principle ... here is this lecture again: And generally this is not discussion but bullying by moderators  not even trying to respond to arguments, only shooting some general remarks without any support. I am going to sleep now, would gladly discuss it tomorrow  but using argumentation instead ... low field is not enough, we need to go to high field like black hole  how exactly could such argument look like: to experimentally distinguish black hole from heavy neutron star? 
Thought experiment: how would physics develop without Einstein?
Duda Jarek replied to Duda Jarek's topic in Physics
What do you mean? We are discussing experiments like gravitational lensing you have brought up  I have just linked some lecture in previous post. 
Thought experiment: how would physics develop without Einstein?
Duda Jarek replied to Duda Jarek's topic in Physics
Are you claiming that light in gravitational lensing do not behave accordingly to Fermat's principle? Interesting, could you support it somehow? I don't know what do you mean by antiGR preaching, but let me remind: this thread was supposed to be focused on argumentation to convince to GR (nonrenormalizable, without Einstein). Once again, using low field arguments would not work as, without Einstein, there could be just developed succeeding terms of Taylor expansion of GR instead. We need strong field arguments like black hole  how they could be used to convince that a given object is not just a heavy neutron star? update: just found some "Introduction to Gravitational Lensing Lecture scripts" http://www.ita.uniheidelberg.de/~massimo/sub/Lectures/gl_all.pdf Mathematics is the same, especially for all low field approximations as first Taylor terms. 
Thought experiment: how would physics develop without Einstein?
Duda Jarek replied to Duda Jarek's topic in Physics
Wave propagation is usually governed by Fermat's principle (similar to the least action principle): leading for example to refraction due to slow down in some medium, allowing e.g. to build lenses  not necessarily using strong boundaries between materials, can be gradient like in gravitational case. GR uses intrinsic curvature instead, but in Fermat's principle it can be interpreted as slowing down in presence of gravitational field. Here is some related paper: https://journals.aps.org/prd/abstract/10.1103/PhysRevD.96.104037 Gravitomagnetic bending angle of light with finitedistance corrections in stationary axisymmetric spacetimes Anyway, bending we observe is low field effect  can be obtained by replacing GR with first terms of its Taylor expansion. The big question is how to conclude nonrenormalizable GR from them? I am afraid that convincing arguments might require strong field effects like black holes ... 
Thought experiment: how would physics develop without Einstein?
Duda Jarek replied to Duda Jarek's topic in Physics
But finally from general comments that "everything confirms Einstein", we are getting to real discussion  about concrete experiments, as this is a bit more complex. 
Thought experiment: how would physics develop without Einstein?
Duda Jarek replied to Duda Jarek's topic in Physics
Searching for materials about Mercury precession, they usually refer to GEM, e.g.: https://www.worldscientific.com/doi/abs/10.1142/S2010194517600527 But Heavisides' 1893 GEM paper has only citation before 1950 (now 315): https://scholar.google.pl/scholar?hl=en&as_sdt=2005&sciodt=0%2C5&cites=5741552482440482063&scipsc=&as_ylo=1800&as_yhi=1950 It looks like just nobody was aware of this paper back then (?) Update: from https://arxiv.org/pdf/grqc/0207065.pdf 
This is discussion forum, I have created general thread to discuss violation of baryon number  among others asking if it is possible, if so where it could be observed, how it could be verified. I don't know if it happens in neutron stars, I have never claimed it  this is only one of topics to discuss here, I am asking for arguments in both sides. Maybe indeed it should be neglected or "discarded in 30 seconds", but I don't know the argumentation behind it and would gladly learn.

Baryon number violation is not my idea, but a phenomenon required e.g. for baryogenesis, Hawking radiation, supersymmetry, GUT, sphelatron and many others. I am not claiming anything, only asking, trying to discuss if it could also have other astronomical consequences, for example those which (as they claim) cannot be explained in standard way, like this https://www.space.com/35846brightestfarthestneutronstardiscovered.html "Astronomers have discovered the brightest neutron star ever found. This extremely dense object is 1,000 times brighter than researchers previously thought was possible for neutron stars (...) This is one of the questions the scientific community needs to answer in the next years "

Thought experiment: how would physics develop without Einstein?
Duda Jarek replied to Duda Jarek's topic in Physics
I am just referring to Wikipedia (e.g. copy&pasted table), which uses GEM all around for low field GR effects ... and don't see any "off topic claims"  please specify. Bending wave is universal for propagation with different speeds  is not limited to water, or EM waves: https://en.wikipedia.org/wiki/Refraction https://en.wikipedia.org/wiki/Structural_acoustics 
Thought experiment: how would physics develop without Einstein?
Duda Jarek replied to Duda Jarek's topic in Physics
The main question to discuss here is if without Einstein we (or some other civilization) would get to GR. Alternative way is introducing succeeding terms of Taylor expansion of GR  the question is what could be the "extraordinary evidence" to convince that it is necessary to introduce intrinsic curvature of spacetime in nonrenormalizable theory (GR). Finally some experiments, so let's discuss them:  from https://en.wikipedia.org/wiki/Tests_of_general_relativity : so it is mainly about gravitoelectric effects  isn't it part of GEM? Imagine analogous EM situation: circulating charge produces magnetic field, which leads to Lorentz force precessing the orbit. I don't know why they didn't use Heaviside? Maybe they just were not aware (?), he is not mentioned in https://en.wikipedia.org/wiki/Twobody_problem_in_general_relativity It seems Heaviside's paper had one citation before 1950: https://scholar.google.pl/scholar?hl=en&as_sdt=2005&sciodt=0%2C5&cites=5741552482440482063&scipsc=&as_ylo=1800&as_yhi=1950 Anyway, if Heaviside's GEM is approximation, then just use the proper one from Taylor expansion of GR.  regarding light bending, we observe it also e.g. in water  due to different propagation speed. Without Einstein one could use this explanation  requiring some slowing down of EM propagation in gravitational field  some coupling between EM and gravity. These are low field effects  can be explained by using a few first terms of Taylor expansion of GR  one could estimate/use them not being aware of complete GR. I am afraid that to get to really convincing arguments, we would need to go to high field effects  like distinguishing neutron star from black hole  how such argument could look like? 
What do you base that on? https://en.wikipedia.org/wiki/Proton_decay says proton > positron + pi0 and pion further decaying to gammas, which from energy conservation need to carry ~1GeV energy in this nearly complete matter>energy conversion. I am saying saying "baryon decay" because such matter>energy conversion would also concern especially neutrons. There are many astronomical objects they say with orders of magnitudes higher energy production than can be explained, but I didn't see hypothesizing baryon decay (?) Yes, I am referring to baryon number nonconservation: as proton/neutron decay into nonbaryons.

Because baryon decay would be nearly complete mc^2 matter > energy conversion. If happening in core of neutron star, it could greatly increase energy production  above what we can explain without it, and there are observed such unexplained examples. How many nuclear fusion events should they expect in all these proton decay experiments?

Indeed charge conservation is quite different from baryon/lepton number conservation. Regarding "the same way it disprove nuclear fusion", I have only meant that fusion also don't happen in room temperature water, but we shouldn't conclude that it disproves fusion  which requires much more extreme conditions. However, unobservation of proton decay in room temperature water is often seen as disproof, made it an exotic concept not worth considering. Regarding hypothetical confirmation for astronomical objects, if it would happen in one of the most extreme places: core of neutron star, we wouldn't have a chance to see some additional spectral lines, only excessive energy, like this "1,000 times brighter than researchers previously thought was possible for neutron stars " of NGC 5907 X1.

Thought experiment: how would physics develop without Einstein?
Duda Jarek replied to Duda Jarek's topic in Physics
Where??? There was some criticism of GEM, which accordingly to a few Wikipedia articles like https://en.wikipedia.org/wiki/Gravitoelectromagnetism was confirmed by Gravity Probe B, its examples are frame dragging, LenseThirring. But if you have some allergy to this well established GR approximation, then just take a few first terms of Taylor expansion of GR  low field approximations, which are used for calculations for most of these experiments Without Einstein they could be seen as found succeeding terms added in Lagrangian  like they did for Standard Model (maybe also first Taylor terms of some TOE?) Please elaborate how without Einstein one could extrapolate from these terms that we need to introduce intrinsic spacetime curvature in nonrenormalizable theory?