Quantum Fluctuation : Causal

Discussion in 'Physics & Math' started by The God, Mar 12, 2017.

  1. The God Valued Senior Member

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    Yes, we are in a time of progress in observational cosmology thanks to tremendous advancement in state of art equipments. But the issue still remains that is data interpretation....there could be confirmation bias.
     
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  3. rpenner Fully Wired Staff Member

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    But, that is not a concrete claim so is isn't worthy of consideration. The burden is on you to demonstrate specific bias or error, not merely to raise the vague possibility that someone left once their thumb on the scale somewhere in this history of physics and astronomy which both materially affects modern science and has not been discovered yet.

    When you evade that burden, all we are left with is naked denialism without basis in fact-based argument, the pseudo-skepticism of a science outsider, aping the form of rational skepticism without any of the epistemological benefits (like a specific course-correction on how to do better). We are left with a vision where the personal incredulity of a science outsider is being held in higher esteem then the body of work of thousands of critical experts. That's a recipe for cults, schism and nationalism, not science as the body of knowledge which is the common inheritance of all mankind.
     
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  5. karenmansker HSIRI Banned

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    I disagree!
     
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  7. The God Valued Senior Member

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    Basically you are begging that look so much great work has been and is being done by science, so there cannot be any hanky dory...
    You cannot be so naive not to know the establishment bias.
    It gives me a feeling that you are politician-scientists, always in sync with authorities. For example you were all for HR but when schemelzer highlighted a genuine problem, you went silent. Be vigilant, speak up. Do not every time call others as science outsiders, do not show your arrogance at every questioning, be a worthy insider, not an authority-saluting-insider.
     
  8. rpenner Fully Wired Staff Member

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    In post #58 you said you didn't want to “get into English” in this thread. This line is an example of why that's not helpful.
    Beg is a transitive verb which means 1) to ask earnestly for something or 2) to require something as a necessity or 3) to evade something, which is not how you used it.
    Hunky-dory means everything is satisfactory.
    Hanky-panky is behavior which is improper.

    That's not what I said. I said you can't nakedly assert that a physical theory is wrong just because you don't like it. A physical theory is only wrong if it does not precisely predict the behavior of observable phenomena within its applicable domain. Your insistence on causality in the OP is given as a mere philosophical point of view, not one reasoned within quantum theory.

    I don't see how that applies when you have the anti-establishment bias where you make baseless charges against science because it is mainstream or uses math. This makes you look like someone too lazy to pursue answers.

    The authority here is the concordance of physical theory with empirical observation. Secondary authorities, like the tide of the majority of professional opinions of relevant professionals, matter mostly because you don't have the tools to deal with the primary authority.

    I felt he was mangling an antique (i.e. circa 1980) argument, but since he supplied no references and you launched a barrage of whisper campaigns against post-1905 physics, I didn't have time to pursue it. No one has the right to demand a well-researched reply, not even wrong people.

    But I would point you to section 7.1 of Quantum Field Theory in Curved Spacetime and Black Hole Thermodynamics (Wald, 1996) and section 4.6 of Quantum Field Theory in Curved Spacetime: Quantized Fields and Gravity (Parker and Toms, 2009), two graduate-level textbooks which reach the conclusion, backed by specific citations of papers, that there is no reason to suspect the objections raised by Schmelzer are valid rebuttals of either Hawking radiation or its thermal spectrum.

    My job is to enforce the authority of the site owners here. Part of the job is enforcing the policy which distinguished between proper science and fringe ideas outside the methodology of science. My advice to you is to avoid trolling and to develop your arguments better for an audience which is not going to start out sympathetic to your claims but needs to be convinced by fact-based logical arguments.
     
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  9. The God Valued Senior Member

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    I will refer to the books but till then over to schmelzer...if he cares to respond.

     
  10. exchemist Valued Senior Member

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    I say, your English has suddenly got a lot better! Very erudite!

    Please Register or Log in to view the hidden image!

     
  11. The God Valued Senior Member

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    Are you so careful with the use of words here?

    Rpenner has a problem, he cannot explain science descriptively...he uses complex maths which not many bother to read.....on the other hand he is too good in descriptive essay writing on everything other than science. Fighting with him will not yield anything, because he is the Mod, he of course talks science and knows his subject pretty well, while on the other hand I am mostly harping on issues around few of these topics. He is bound to get irritated because he knows that these issues are either carpeted or sorted out with hand waiving. So he will ask detailed mathematical treatment or evidence or citations. Evidence and citations are ruled out and I cannot do that kind of maths.
     
    Last edited: Mar 24, 2017
  12. exchemist Valued Senior Member

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    I appreciate clarity and try to be clear myself, yes. But I have the advantage of English as a first language and an education that valued the use of it, so I'm lucky in that respect. (Though I often fail to make myself clear, nonetheless - quick replies on the internet are dangerous!)

    Rpenner can be hard to follow sometimes and I don't always read all the maths but it's clear he knows his science. I think he is an excellent mod for the hard science sections and remarkably patient. This place is a lot more tolerant of wacky ideas, or slack thinking, than most but has recently become, thanks to the departure (and/or moderation) of a few individuals, a pleasantly civilised place to discuss.

    I am not sure why you say evidence or citations (by which I presume you mean references to published writings) are "ruled out". Why? I try, when I make a non-trivial or possibly contentious assertion, to back it up with something to show it is more than me just talking out of my arse. Can't you support your viewpoints in this way? I think it's a good thing to do, whenever you can, as it lowers the temperature of the discussion, making it less likely that people start accusing each other of talking rubbish, being ignorant, or whatever.
     
  13. The God Valued Senior Member

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    The strength of establishment and career issues of scientists are known to all, who tried to do something objectively critical. Schmelzer has expressed this very vocally on this site. He is a known scientist.

    And as far as Rpenner Modding ability is concerned, I do not wish to comment beyond a general observatiom that its a known fact that a skilled person on any subject, may not be a good administrator of activities around that subject.
     
  14. The God Valued Senior Member

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    I missed that in the barrage of unwarranted semantic content by you. you dismissed schemlzer Trans Planckian issue as antique (1980) and mine as ancient history (1905). Let schmelzer respond on his case, but my ref to 1905/1916/1998 was on cosmological constant, which is still a substantial pain. You may like to refer to this arxiv paper https://arxiv.org/abs/1502.05296, which is of 2015 and still not ancient and describes this as the "mother of all the Physics problems" and various works on resolving this. I still maintain that you are averse to discussing issues in fair and transparent manner, that is one aspect of high handed establishment bias.
     
    Last edited: Mar 25, 2017
  15. rpenner Fully Wired Staff Member

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    Background
    The accelerated expansion was discovered in 1998, when two independent projects, the Supernova Cosmology Project and the High-Z Supernova Search Team simultaneously obtained results suggesting an acceleration in the expansion of the universe by using distant type Ia supernovae as standard candles.[5][6][7] The discovery was unexpected, cosmologists at the time expecting a deceleration in the expansion of the universe, and amounts to the realization that the universe is currently in a "dark-energy-dominated era". Three members of these two groups have subsequently been awarded Nobel Prizes for their discovery.[8] Confirmatory evidence has been found in baryon acoustic oscillations and other new results about the clustering of galaxies.
    ...
    The most important property of dark energy is that it has negative pressure which is distributed relatively homogeneously in space.

    \(P = w c^2 \rho\)
    where c is the speed of light and ρ is the energy density. Different theories of dark energy suggest different values of w, with w < −1/3 for cosmic acceleration (this leads to a positive value of ä in the acceleration equation above).

    The simplest explanation for dark energy is that it is a cosmological constant or vacuum energy; in this case w = −1. This leads to the Lambda-CDM model, which has generally been known as the Standard Model of Cosmology from 2003 through the present, since it is the simplest model in good agreement with a variety of recent observations. Riess found that their results from supernovae observations favoured expanding models with positive cosmological constant (Ωλ > 0) and a current acceleration of the expansion (q0 < 0).[15]

    https://en.wikipedia.org/wiki/Accelerating_expansion_of_the_universe
    Background
    schemlzer's trans-Planckian critique of the math of some derivations of Hawking radiation is made antique by later work and later approaches. https://arxiv.org/pdf/1410.1486.pdf

    While Special Relativity (1905) is still excellent physics in all areas where gravity can be neglected and extends naturally to one-parameter General Relativity (1916) and two-parameter General Relativity (1917). Einstein's reasons for introducing the cosmological constant in 1917 are mathematically compatible with his 1916 reasoning about general physical laws, but were motivated by tissue-thin aesthetic reasons and the crude observational record of the time which confused the Milky Way with the whole of the universe.
    The current cosmological debate of whether the missing 70% of the universe (required to make it approach the flatness found empirically) is synonymous with the cosmological constant of Einstein's two-parameter General Relativity (1917) or is something else, dark energy, which has a particular equation of state that just happens to mimic the cosmological constant in one-parameter General Relativity (1916) has not yet been resolved by observation.

    Early attempts to glue General Relativity with quantum field theory in the 1960s discovered that the assumption that vacuum energy was real led to a runaway term which acted like a huge cosmological constant and which would have be (nearly) balanced by a negative cosmological constant of about the same magnitude just to match observation of the effective cosmological constant. Many people consider this to be the cosmological constant problem.
    Reply
    Your cited paper ( https://arxiv.org/abs/1502.05296 ) doesn't quite match up with what you say.
    It says that it is irrelevant to solve the problem of why the effective cosmological constant is so much smaller than that given by vacuum fluctuation considerations because perturbative theory and other techniques suggest there is no simple way to reconcile the two because quantum field theory has a runaway problem with degrees of freedom at high energy and what solutions work at low energy are not expected to work at high energy unless gravity and quantum field theory are built together in a way to make the effective cosmological constant stable.
    Basically, this author says the solution is to be found in certain features of a quantum theory of gravity, a successor to Einstein's General Relativity. In such a modification to gravity, the effective cosmological constant cannot be calculated ab initio, but can only be measured like the effective electron mass in the renormalization schemes of perturbative quantum mechanics which is stable because of the symmetry of the renormalization group.
    I don't see how that connects with your complaint that circa 1998 it was discovered that the expansion of the universe matched the predictions of GR best with an effective cosmological constant of about 7/3 times the amount of matter (both normal and dark) as modeled in ΛCDM cosmologies.
    Conclusion
    So yes, there is a real problem in that General Relativity and Quantum Field Theory are not married into a successful theory of quantum gravity yet, a marriage where at least one will have to undergo changes in predictions of behavior. And yes, there is an observational problem that we don't know if dark energy is "stuff" or a cosmological constant relating to the effective action of gravity and the vacuum. And yes, Einstein introduction of a non-zero cosmological constant was done for the wrong reasons, even if mathematically sound and every interestingly compatible with detailed observations today which bound the w of "dark energy" to be −1.006±0.045 which is completely compatible with the w=−1 of an effective cosmological constant.
    https://arxiv.org/abs/1502.01589
    (Another source cites −0.97±0.05 )
    http://pdg.lbl.gov/2016/reviews/rpp2016-rev-astrophysical-constants.pdf
    See also table 27.2 of http://pdg.lbl.gov/2016/reviews/rpp2016-rev-dark-energy.pdf

    But all that says is that science doesn't yet know everything.You haven't demonstrated that either General Relativity or Quantum Mechanics is wrong because the successor theory may preserve the all predictions of either or both. You haven't argued that either 1-parameter General Relativity or 2-parameter General Relativity is better because we don't know from observations if we have "Dark Energy" or a "Cosmological Constant" (or both).

    Worst of all, rather than calling for more research, you complain when new observations (like those in 1998) improve the state of knowledge and make us less dependent on fact-free speculation like Einstein's 1917 "blunder."

    I wonder what it is that you think science is if learning new stuff about the universe is to be discouraged in your world view.
     
  16. The God Valued Senior Member

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    Thats a very fair conclusion by you. First time you did not bulldoze your way through.

    Now the problem is this Quantum Gravity; despite the unrelenting work by top guys like Ashtekar, Baez, Rovelli and Smolin this QGT is not even in sight. It is not that we do not know what we are looking for, it is not that we do not have experimental finesse, it is not that we lack equipments...still this QGT is alluding us? It is quite likely that our desire to keep the GR alive is killing us.


    Thats not a fair conclusion of my stand. In fact it is quite opposite to what I am saying. The tendency of last few decades is to latch on to GR, the tendency is to come up with absurd ideas and somehow explain the new observations with weird looking maths in order to save on GR, the tendency is to wait in utter despair that look somehow one day QGT will come and solve the problem associated with marriage of GR with QM. New stuff and New Ideas, from any source, are ridiculed on this topic.

    Mercini was ridiculed when she used the very HR to negate the Black hole formation, Abhas Mitra was ridiculed when he proposed ECO (and now MECO), Steinhardt is being ignored when he said that the very theory, the inflation which he is a founder, is not ok. Why : The only conclusion is that mainstream is too much invested in GENERAL RELATIVITY. Thats for you to find out who is suffocating the new ideas and new stuff!!
     
  17. Schmelzer Valued Senior Member

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    It isn't. And, BTW, it is not the math which has the trans-Planckian problem.
    Nobody has questioned AFAIK the results of Paranjape, Padmanabhan, Radiation from collapsing shells, semiclassical backreaction and black hole formation, Phys.Rev.D 80:044011 (2009), arxiv:0906.1768v2
    For a quite simple reason that this would be extremely hard: Stable states do not Hawking radiate, because they also have a stable vacuum state. This, in particular, invalidates the Unruh radiation analogy (5.2, 5.3 too).

    Then, you can modify the equations of GR so that you get stable stars instead of black holes with radius at an arbitrary small distance from the horizon $r_S+\varepsilon$, thus, with arbitrary large surface time dilation. This modification essentially changes only trans-Planckian physics. Once by modifying trans-Planckian physics you can get rid of HR, the trans-Planckian problem remains. So, it is very easy to get rid of HR. Contrary to Carlip's claim: "It turns out to be very hard to “break” Hawking’s results: standard thermal Hawking radiation, with the usual Hawking temperature, appears even in models that never involve Planck scale physics".

    What about all the other derivations mentioned by Carlip? With Periodic Greens functions, anomalies and so on? Most of them are simply irrelevant, because there is no doubt that Hawking radiation is derived correctly in semiclassical gravity - so one has to expect that every other method applicable to semiclassical gravity gives the same result. The trans-Planckian problem does not say that the derivation is invalid, it argues that to think semiclassical theory works in the heavily trans-Planckian domain is nonsense. So, the point of the other methods cannot be "this is another method which works in semiclassical theory, and it gives the same result". This is pointless, because nobody doubts the semiclassical computation. It should be "this method does not use anything trans-Planckian". So forget anything which refers to renormalization (which obviously needs trans-Planckian frequencies) and anomalies (which are a field theory version of a Hilbert hotel).

    There are other points which can be ignored because it is not the point of the trans-Planckian problem, namely whatever derivations which make the point that if there is radiation, it will have thermal character with Hawking temperature as its temperature. Because nobody doubts that. The paper I mentioned above says "We first show that any shell of mass M which collapses to a radius close to r = 2M will emit approximately thermal radiation for a period of time. ... Later ... the flux from such a shell will decay to zero exponentially". Nothing suggests that during this decay the flow will no longer be Planckian.

    But Carlip is nonetheless correct that HR appears also in models that never involve Planck scale physics. How this? Very simple, all you need to get some radiation is some change. All you have to avoid is a stable frozen star. So, if you cut away trans-Planckian frequencies in such a way that the trans-Planckian structure is not stable for a stable BH, but has some permament flow, you will get some radiation. And some radiation is all you need. This can be seen in Carlip's paper too:

    Emphasis mine. What hides behind this preference for a "freely falling observer" is simply the freely falling trans-Planckian structure, which creates a permanent inflow into the black hole, even if this inflow consists only of some trans-Planckian elements which are not visible at large distances. People who consider these things know about this. Like Jacobson:

    So, if you plan to prove that there is HR in general, you have to introduce conditions which exclude the static lattice or similar things. Here is how this is done:
    Another critical point with all the "HR remains even if we cut trans-Planckian frequencies" is the region of origin. In the semiclassical picture, we can identify the region of origin. It is the trans-Planckian environment of the BH. In the picture with trans-Planckian frequencies cutoff we can identify it too. It is the region where the cutoff becomes relevant, and is completely defined by the cutoff. In particular, it does not shrink in time, because (if) the cutoff does not change in time. So, this is simply a different effect, with a different origin, and even a different region of origin, namely one which depends on the trans-Planckian physics used to cut trans-Planckian frequencies off, radiation which would not be created in this region without trans-Planckian physics, with semiclassical gravity alone.
     
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  18. The God Valued Senior Member

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    Somehow it is not appealing that quantum fluctuation is acausal. Although there is a huge philosophical debate on causality, but in this case science has conveniently reduced philosophy to back benches.

    But the nature does not produce anything out of nothing. It certainly satisfies physics that from nothing virtual particles / anti particles got popped in, it just shows that we do not understand this nothing yet. The physics would change the day we succeed in cracking this 'nothing'.
     
  19. karenmansker HSIRI Banned

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    Agree
     
  20. Seattle Valued Senior Member

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    Officer: "Sir, you were going 120 mph."
    Werner Heisenberg: "Great. Now I don't know where I am."
     
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  21. The God Valued Senior Member

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    That's not the cause. That is the explanation.
     
  22. Seattle Valued Senior Member

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    It's neither the cause nor the explanation. It's a joke.
     
  23. The God Valued Senior Member

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    Of course, it's a joke.

    But ref to underlying uncertainty principle has a connect with OP.
     

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