Let me be the first to tell you that you can not possibly "really" understand QM. I know bc I am in the same boat.
A beautiful star cluster that's relatively close to Earth: just 200,000 lightyears away.
- Thread starter JeffKeryk
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I'm not a physicist, however I do read time to time on the latest theories/trends. It appears to me that the Big Bang Theory is no trouble whatsoever. What is needed is better models and understanding of galaxy formations. As Dr. Becky said, physicists are not worried one bit about this finding. They're excited. I think things were taken out of context and some jumped on it quickly.
I took physical chemistry 1 and 2 as an undergrad and p-chem 2 is all quantum mechanics but even with this I never had a "working knowledge" of the math. The best you could do was follow along. I could probably still figure out the wave function for something simple like spin up or spin down for an electron in hydrogen and I understand the mathematical rationale of the uncertainty principle but I have a graduate-level QM text at home and yeah...nope...orders of magnitude more difficult than my p-chem class. However, light years ahead of most people...
MolaKule
Staff member
Well, you can if you study some supplemental texts such as, What is Quantum Mechanics? A Physics Adventure, by transnational College of LEX, Language Research Foundation, Boston.
Then one can transition to Liboff's text, Introductory Quantum Mechanics.
I also have previously recommended, M.S. Longair, Theoretical Concepts in Physics, Harvard University Press,
The concepts aren't difficult and they are very accessible but when you start getting into triple integrals and partial differential equations and complex matrices and bra and ket vectors and dot products it gets out of hand quickly. Those concepts by themselves are not too difficult but when applied to QM it is challenging. Even then I understand what the equations are doing in general but the ability to get the finer details from them or manipulate or even to go from a few equations and some assumptions and then to derive a new equation/concept? Nope...
If you read biographies of some of the great physicists of all time some of them struggled for weeks and months working 24-7 to understand some of these equations and concepts fully.
I have Susskind's book and that is baby QM. It covers ket and bra vectors but it is very basic and basic mathematical concepts.
Principles of QM by Shankar - legit next level and very difficult.
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MolaKule
Staff member
Sabina (Sabine Hossenfelder) has an explanation of some of these seemingly contradictory concepts about the Big Bang starting at about 0.57:
OK, I think we have explored the 'taken out of context' thing to its limit.
What good are additional models if those models are based on faulty, highly questionable hypothesis?
In post post #7, I showed that M.S. Longair's comments on Wagner's charts "...stellar nucleosynthesis cannot account for the abundance of D, 4He, 5He, 7Li," did not come from Lerner but from Wagner, circa 1977, and Longair's analysis with respect to cosmic mass density.
I think I have shown that the BB singularity is in trouble because it does not have an event horizon, post #33, "A principle in physics which forbids the existence of a naked singularity, is the “cosmic censorship hypothesis”, the principle states that all singularities must be surrounded by an event horizon."
I showed in post #25, that R. Lieu, an astrophysicist stated, "Cosmology is not even astrophysics: all the principal assumptions in this field are unverified (or unverifiable) in the laboratory … ." LCDM cosmology: how much suppression of credible evidence, and does the model really lead its competitors, using all evidence? 17 May 2007, arxiv.org/abs/0705.2462v1.
This seems like an accurate analysis because ‘cosmologists’ today are inventing all sorts of stuff that has just the right properties to make their theories work, but stuff that has never been observed in the lab. Lieu says that ‘because the Universe offers no control experiment, i.e. with no independent checks, it is bound to be highly ambiguous and degenerate.’ They have become ‘comfortable with inventing unknowns to explain the unknown.’
Lieu then lists a few counter evidences to LCDM inflation cosmology, all of which have been, or are in the process of being, published in topmost astronomy journals. They are:
- the number density evolution curve in galaxy clusters (there is a massive dark matter problem in them also) does not agree with the LCDM prediction to 7σ statistical significance,
- only 50% of the baryons predicted by the LCDM model seem to exist at low redshifts—called the missing baryon problem,
- no explanation for the soft X-ray excess from clusters, Abell 3112, for example,
- the disparity between the values Sandage et al. (H0 ≈ 62 km/s/Mpc) and Freedman et al. (H0 ≈ 70 km/s/Mpc) determine for the Hubble constant from two independent analyses of HST data,
- galaxy groups like our own Local group seem to harbor too much matter,
- very feeble SZE detected by WMAP—no shadow cast in the foreground as expected from a background source; this has now been tested by separate authors respectively on two sets of 31 and 100 rich clusters,
- Axis of Evil in the CMB octopole and quadrupole expansion terms correlate with HI clouds in the Galaxy, where Lieu concludes that a significant fraction of the WMAP anisotropy at the primary acoustic peak is not cosmological,
- dwarf galaxy rotation curves. The data indicate constant density cores, whereas LCDM halo profiles have central cusps.
And lastly, post #42, I pointed out that Dr Michael Turner is a theoretical cosmologist at the University of Chicago and concedes that cosmology is different from experimental science and is instead historical science. “The goal of physics is to understand the basic dynamics of the universe. Cosmology is a little different. The goal is to reconstruct the history of the universe.” (Cho, A., A singular conundrum: How odd is our universe?, Science 317:1848–1850, 28 Sept 2007).
"The goal of physics is to understand the basic dynamics of the universe." That's what is known as Operational Science.
"Cosmology is a little different. The goal is to reconstruct the history of the universe." That's what is known as Historical Science.
The Scientific Method should apply to both sciences, but the Historical Science advocates seem to ignore it for the most part.
So if you want to base your information set on popular science articles (mostly written by non-scientists) then that is your choice, but there are physicists and astrophysicists out there who are examining the minute details of the BB hypotheses and are finding them to be questionable, if not downright faulty.
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Here are Susskind and Shankar side by side on the topic of the path integral. To really understand QM, you'd have to understand Shankar like you're just reading a novel.
Here is a page from Susskind's book on path integrals and I can follow the math and logic.
Here are some pages from Shankar and it is 676 pages of dense math just like this...THIS is what it means to REALLY understand QM.
If you understand that then you are a smarter and more learned man than I am!
Here is a page from Susskind's book on path integrals and I can follow the math and logic.
Here are some pages from Shankar and it is 676 pages of dense math just like this...THIS is what it means to REALLY understand QM.
If you understand that then you are a smarter and more learned man than I am!
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I've been trying to teach my cats calculus. Maybe we aren't any more ready than they are. 
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Calculus can be understood on two levels.I've been trying to teach my cats calculus. Maybe we aren't any more ready than they are.
Level 1 is just understanding the concepts of the integral or area under the curve, the 1st or 2nd or 3rd derivatives or rate of change over time, limits, etc. Level 1 is easy to understand even if you can't compute anything.
Level 2 is actually understanding how you actually compute the integral or the derivative etc or how to actually use the fundamental theorem of calculus or chain rule or U-substitution. This requires some technical mathematical know-how.
MolaKule
Staff member