Hi there Please Register or Log in to view the hidden image! Theres a few things I am curious about, I was hoping you guys could help me Please Register or Log in to view the hidden image! Just trying to get a sense of the accepted standard ideas (not the postulates or math so much, more their relation to theory and science in general). You guys might be able to provide a more concise, perhaps even detailled, summary of the sort I am after than google Please Register or Log in to view the hidden image! Firstly QM (standard model) -The wave function collapse - is there any evidence that it occurs only during observation, or is it impossible to tell if it happens during other non-"observer" interactions? -Has QM created/uncovered any technologies, or helped any advances? -Are there many alternative models/theories to the standard model that fit with observation? (IDK how well the other interpretations of QM fit or dont, or if there are any other non-QM theories that make predictions and fit observation). Are there any modern models that don't really fit observation? And relativity (Both GR and SR): -Are there many alternative models/theories to GR and SR that fit with known observation? (Oh, and was lorentz's aether theory proven wrong? I am no aether nut, just curious about the history) -Oh, and if space itself can cause travel faster than light (as in distant galaxies), could that not be used in theory(such as a "spacial compression/warp" in around a space ship) to violate causality, and SRs postulate of no information travelling faster than light? If anyone can answer just one of these questions, i would find it most helpful - I figured it would be better to ask these as one topic, so as not to flood the forum with posts.
Welcome to the forum. I ain't touching the QM. My only experience with QM is with the Schrödinger equation in P-Chem and I only remember, uh well that's about it. GR and SR do an excellent job of fitting the observations so there is no current viable alternatives (IMO). Of course there is a lot of work goingon to a determine a quantum explanation of gravity. I don't think that you could say that the aether was proven wrong but it was certainly shown to be unnecessary. Not to mention the properties of the aether would have to be so exotic that it was a relief when it was not necessary - ie light propegates through a vacuum no medium necessary. When you go for a walk you are moving many orders of magnatude faster than the expansion of space. The distant galaxies have a high recession velocity because of the additive effect of the expansion over the distance of billions of ly. So if we harnessed the expansion and used that to move, an old guy in a walker would kick your butt.
Quantum Theory is considered to be an extremely accurate description of reality & I do not think there is another considered to be better. A conscious observer is not considered necessary for Wave Function collapse: At least there are few who consider the observer to be necessary. It is generally believed that the collapse occurs when a Quantum level process or entity causes an effect at the classical level. For example: A photon is emitted when an electron in an atom changes from one energy level to another. To use the now obsolete Bohr "Solar System" model of the atom: When an electron changes from one orbit to another. The above is reasonable, but a poster whose knowledge of QT is better than mine might object to my description and/or have a better example. The photo electric effect (described in one of Einstein's 1905 papers) is used for automatic opening of doors & similar gadgets. Lasers & masers are based on Quantum Theory effects. Tunnel diodes & some other electronic gadgets are based on Quantum Theory. BTW: Einstein is the true father of Quantum Theory & was given the Nobel prize for his 1905 paper on the photo electric effect. He was considered a bit of a crackpot for a year or two beacause he claimed that energy was quantized & that the mainstream view of Planck's Black Body radiation paper missed this critical issue. It has been suggested that he was given the Nobel in 1921 for the photo electric effect paper as an apology for mainstream physicists deriding his belief in quantized energy. At that time it was considered taboo for a person to be given two Nobels & also believed that General Relativity would always be considered a monumental achievement & would always be credited to him, thus not requiring the acknowledgment of a Nobel.
Planck is the father and Einstein the photo-electric son, Phillip Lenard is the mother (for discovering threshold frequency). Planck came up with quantized energy but personally derided Einstein for his photon theory. And no, I don't think the Nobel committee thought so much into that. Yeah Dino, this "conscious observer" concept has been abused by popular science outlets and quantum woo bullshitters. It is not so much a classical effect. Rather, "observing" in their experiment is not akin to watching a movie. You actually have to disturb the experimental setup in some way. D-Wave Systems claims to have constructed a 128-qubit quantum computer. Lots of skeptics on this one. String theory? Which can't really be tested. There's also Super-symmetry. Most interpretations of QM predict the same experimental observations. There are shitloads of models that don't fit, obviously most of them have been discarded or peddled by cranks. According to MMX the aether was proven wrong. Apparently Einstein claimed he had never heard of the experiment at that time. As the story goes, Einstein reformulated Lorentz's theory into SR, which of course requires no aether. One alternative to GR is Brans-Dicke. There is theoretical inconsistency between GR and QM. Two competing explanations are String theory and Loop Quantum Gravity You mean an anti-telephone? You'll need to ask a GR and cosmology expert on that one.
Thanks for your welcome origin Please Register or Log in to view the hidden image! And thanks all for your answers! Thanks for your detailed answer. Does loop quantum gravity make experimentally testable claims that we might one day be able to explore? (as opposed to the obtuse string theory, which seems not to) If all the interpretations of QM fit the observations.....why is one more popular/accepted than the others? beleif? just preference of beleif? If by MMX, you mean micheal-morley (I think its called), lorentz developed his theory to fit those observations of the apparent zero change in the two way speed of light, after the fact. He apparently "fudged" aether theory, in his new equations, derived from maxwells, by saying lengths contracted in response to the aether. Einstein reforulamated this to exclude aether, but I think they are mathematically equivilant? Which is to say, the new formulation was never proven wrong, people preferred einsteins ideas, because they didnt need aether? Not sure if thats true, but that is my understanding. Aether theory is not something I am into, but I do find instances or the possibility of mathematical equivilance interesting, if that is whats happened here. Ill look up Brans-Dicke, cheers Please Register or Log in to view the hidden image! Oh, and I didnt exactly mean an anti-telephone per se. What I mean is, space is said itself, not to be constrained by the speed of light. Assuming is has geometry, as per SR, then one could fold it or create a wormhole, or contract or expand it in some way, that you are travelling faster than light. For example in the supposed early universe, in the first moment, everything is supposed to be expanding faster than light, but simply because spacetime itself is expanding so, not because the matter is travelling that fast. Well, heck even if it was, conciousness has not been explained or quantified in any substantial way (I have a double psychology and philosophy major). I just thought it might be nice if it was proven that an observer was not required, but I suppose this is probably impossible? Thanks again Please Register or Log in to view the hidden image!
LQG is an attempt to make QM and GR compatible. At the particle level, the effects of gravity are entirely insignificant. Physicists wanna use cosmological evidence. http://phys.org/news/2012-01-physicists-loop-quantum-gravity.html Most probably so. Fitzgerald came up with this concept first. Yes and no and yes to your last two questions. By the early 20th century, physicists were very convinced that there was no aether, so they considered Lorentz's aether theory proven wrong. I have no clue about this one. Was or was not? No conscious observer is required, the "observer" is actually a modification of the experimental setup.
Eram: Planck derived equations relating to Black Body radiation & indicated it was a quantized phenomon, but did not make any further claims relating to quantized energy. Einstein was the first to claim that energy in general was quantized. Note that Einstein was derided by mainstream physicists for his views relating to quantized energy. The following is an interesting comment by Einstein when asked about the outcome of the controversy. The above is a paraphrase, not a precise quote. BTW: I think that Planck fudged some of the data to make it fit his equations. His views relating to Black Body radiation were essentially correct.
The above examples of the photoelectric door openers, lazers and masers and certain electronics components - did those concepts directly arise from quantum mechanics models or discoveries (ie did their inventors use the theory itself to produce/design the technologies)? Its not my most burning question at all, but its nice to know. I am very happy to have received the fabulously informative replies from all thread contributors so far. Thank you very much for your time and patience Please Register or Log in to view the hidden image! Much appreciated. Probably the only query I still remain curious about now, is can space-time geometry be used to "violate causality", under GR and SR? I guess its a pretty theoretical and thus practically irrelevant scenario, but I also guess the math itself would probably say something about this.
An effect coming before its cause. Like arriving back somewhere from a round trip before you leave on that trip, for example.
The tachyonic anti-telephone is the only example I can think of. Other than that, there is no causality violation in SR and GR. Some would say time travel using wormholes though.
I think the act of observation is necessary in order to cause wave function collapse. There would be no way to know if a wave function did collaspe if you didn't observe it, but I don't think that is the reason why we don't know of such things. The act of observation is an important thing, and it plays a key role in quantum mechanics even though we don't understand exactly what that role is and how it has an effect on wave functions. I wouldn't say the Bohr model is obsolete, and I don't think Bohr even agreed that electrons where quantized. He even was involved in developing quantum theory. People act like he lived in the time of Newton, but he actually worked with other scientist that developed modern atomic theory. His name has just been dubbed for this model, he just discovered that there are orbitals and we still believe this, it is just the location at these orbitals isn't really known. The wave function collaspe as you describe it in the atom is not the same as when there is an act of observation. When you observe a particle it goes into a single state. When the particle jumps to orbitals, the wave function just in a sort of way cancels itself out. So the wave isn't even present in a particle jump, and in observation it is present it just is in one state. I think you have gotten these concepts confused. They do not describe the same interaction. Two totally different things would be happening there.
No one knows what causes the expansion of space, let alone use it to apply it to anything. It has been dubbed dark energy. They call it this because they don't know where this energy comes from. The properties of it just doesn't fit with causes that people have tried to come up with. It's behaivor is unlike any other force we know. I think Guth has shown that the amount of inflation can be proportional to the amount of mass created in the early universe. It only hints at some type of conservation of inflation energy and mass.
It is always so humorous to watch you confidently proclaim what 'science thinks', when what you are really doing is confidently proclaiming your ignorance.Please Register or Log in to view the hidden image! The expansion of space is not caused by dark energy. The acceleration of the expansion is due to dark energy. The difference is extremely important, and not surprisingly completely lost on you.
I thought I said no one knows what causes the expansion of space... Do you mean to say that the discovery that the cosomlogical constant is increasing, and that is dark energy? Dark energy has been known to exist before it was known that there was an increase in the linear expansion. Dark energy is the description of the linear expansion, not the increase in the linear expansion. The linear expansion itself is an increase of acceleration with distance. The rate of this linear expansion was found to be also increasing. "The acceleration is thought to be driven by dark energy, but what that dark energy is remains an enigma - perhaps the greatest in physics today."- 2011 Nobel Prize in Physics
