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Markus Hanke

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Markus Hanke last won the day on December 26 2019

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  1. 1. Once in 0.5s 2. 12 hours 3. 1ms 4. 1s 5. If you increase gravity, then the atmosphere around you will become more dense, so the exact equivalent of A as subjectively heard by someone will be found at a different frequency. What exactly that frequency is, is not trivial to work out, but in any case has nothing to do with time dilation. 6. Again, increasing local gravity will change atmospheric pressure, so the cooking time will probably slightly change, albeit not because of time dilation. The answer is thus roughly 5min. If you build a mechanism that is artificially synchronised (in terms of ticking rate) with a clock on Earth, you get 1. Once per 1s 2. 24h 3. 0.5ms 4. 0.5s 5. See comment above 6. Roughly 2.5min, see comment above What you are failing to understand here is that time dilation is a relationship between clocks, not something that happens locally to a clock. So, if the process you are considering and the clock are in the same frame, you will never see time dilation of any kind. It’s only when you compare distant clocks at different gravitational environments, or clocks in relative motion, that you can see time dilation. Atomic clocks have nothing to do with electricity. Incorrect, kinematic time dilation is independent of what type of clock you use. A good example here is atmospheric muons (which are elementary particles, and have no internal mechanism at all). You can also directly test this by putting an unstable particle with known lifetime into relative motion (particle accelerator) - you will find that, in the lab frame, its lifetime will be dilated. This is routinely observed in particle accelerator runs. This is not very wise. You were told by the moderators not to link to Dropbox files.
  2. On a purely non-technical, common sense level it all boils down to this - everyone experiences the same laws of physics, regardless of their state of relative motion. Whether you turn on your laptop in your living room, or while coasting along in a rocket at nearly the speed of light wrt Earth, it is going to function in the exact same manner (I use this example, because laptops are complex machines, and make use of most of physics in some way). Any experiment you perform locally in either environment will yield the exact same results, so “being in motion” is not a local, intrinsic property of something, and has no bearing on the form of the laws of physics. When you look at this simple fact in more detail, and ask yourself what premises must hold for this to be true, you’ll eventually arrive at SR, or at least at something very close to it.
  3. The Standard Model is a QFT on a Minkowski spacetime background. I don’t see how it could be constructed without relativity.
  4. The causal explanation is the initial interaction of the particles, when the entanglement relationship is first created. At this point, a correlation between measurement outcomes is established. That’s really all there is to it.
  5. That quantum entanglement is a correlation between measurement outcomes, not a causative action at time of measurement, is indeed the current consensus. I am unsure what you mean by this term. I take it as the current consensus amongst physicists that GR is only an effective field theory, so in all likelihood there is a more fundamental model there, the classical limit of which will turn out to be standard GR (hence quantum gravity being such an active field of research). That more fundamental model is obviously not guaranteed to exhibit the same fundamental symmetries, or bear any resemblance to the notion of “spacetime” at all. Few researchers in the field would disagree with this, I think. Neither locality nor realism are laws of logic, they are features of a mathematical model. A model may lack these, yet still be a good and valid description of physical reality. So you are essentially disputing the validity of GR as a model. The extra constructs you propose - superluminality, ether, preferred frames etc - are neither necessary to explain quantum entanglement, nor is there any evidence that they correspond to anything in the real world.
  6. Standard quantum physics explains entanglement very well, without the need for hypothetical constructs such as superluminality. Also, as you know, correlation does not imply causation.
  7. These aren’t basic principles of science, they are basic attributes of classicality only. There is no good reason to believe they are scale-independent.
  8. My assumption is only that interactions between particles are adequately described by the framework of QFT. This trivially preserves causality, but not necessarily locality and/or realism. It is the current scientific consensus. You can choose to not follow that consensus of course (as you seem to be doing here), but that doesn’t automatically make it “wrong”. You are merely putting forward a different hypothesis. In what sense then are they preferred? What mathematical definition of “preferred” are you using? Can you formalise this for us? I’ll be blunt with you - your very rejection of what you consider “dogma” appears to have become dogma itself for you. The paragraph I quoted the above from really lets that shine through very strongly. At least that’s the vibe I’m picking up. Physics should not become a partisan issue - it is not about metaphysical notions of “right” or “wrong”, but about what model works best in describing aspects of the universe as we see them. Sometimes models are “right” in some circumstances, but “wrong” in others. It’s an epistemological endeavour, not an ontological one. The map isn’t the territory, but it does need to accurately represent the relevant aspects of the terrain, on the relevant scales. Quantum theory / QFT actually does this rather well. As for the specific example of entanglement, since no exchange of information is necessary at the time of measurement, causality never even comes into it at all. By letting go of either realism or locality (or both), we eliminate the very need to exchange information, and hence no artificial notions of superluminality, preferred frames etc are necessary in the first place. Causality is trivially preserved, since the measurement always happens after entanglement has been created, and the outcome of measurements is compared following the usual rules of SR, which again trivially preserve causality. There really is no problem here that needs to be “solved” somehow. The problems only emerge if one demands that notions which appear fundamental in the classical domain (such as locality and realism) must be scale-independent, i.e. necessarily apply on all scales. Why should that be necessarily true? Again, it isn’t about what is right or what is wrong, but about what model best fits the universe we observe. To that end, there is no problem whatsoever in setting aside notions of realism and locality, of absolute time and space, if the resulting model is in good agreement with available data. Realism and locality are not sacrosanct notions somehow built into the foundations of the universe on small scales, rather, they originate in what us humans think the universe should be like; they are a reflection of our own experience, which is, after all, rooted in classicality and the low-energy regime. The unscientific act would be to unquestioningly assume that such notions apply across all scales. There is no apparent reason why they must, but plenty of reason to believe that they don’t. I think even the notion of causality itself may not necessarily be scale-independent. This remains to be seen. To make a long story short - not only is it no problem for me personally to set aside locality and/or realism, but I think it is a perfectly reasonable thing to do, if the resulting model describes very well what it is supposed to describe, while at the same time respecting other principles of physics, such as diffeomorphism invariance. To me, introducing preferred frames and space-like world lines creates many more problems than it solves. Don’t get me wrong here - investigating the implications of such things as preferred frames and space-like separations is quite a valid endeavour, but it doesn’t seem to add any value to physics as it stands. It just creates unnecessary problems and complications. Now, if you could put forward a model that preserves locality and realism without the need to add superluminality and preferred frames...that would indeed be something!
  9. The causal influence happens at the time when the entanglement is first created, which involves an interaction between the particles. This interaction follows the standard rules of QFT. After that has taken place, the system of two particles is described by just one wave function, irrespective of their spatial separation, so that no decomposition of said function into separate, independent parts is possible. This fully accounts for the statistical correlation, no causative exchange of information takes place at the time of measurement. For general curvilinear coordinates, this should actually be \[ \square X^{\lambda } =\frac{1}{\sqrt{-g}} \partial _{\nu }\left[\sqrt{-g} g^{\mu \nu } \partial _{\mu } X^{\lambda }\right]\] I don’t quite understand how the above is even related to the discussion of quantum entanglement?
  10. Apologies if it came across wrongly, the intention was not to make you aware of anything “wrong” you might have said. It wasn’t even directed at you as such, it was more of a general comment. My intent was simply to point out that looking at the situation in terms of geometry of world lines is the easiest and most straightforward way to do it, since that geometry is a quantity that all observers agree on. This is as opposed to reference frames, observers, clocks etc, which makes the situation unnecessarily confusing. But maybe that is just me
  11. This is it, plain and simple. If you have two events in spacetime (start and finish), with initial conditions being equal, there is precisely one unique inertial world line connecting these events. This is geometrically the longest possible world line, i.e. the one that accumulates the most proper time. Formally, this world line is a geodesic of the spacetime, meaning you have \(a^{\mu}=0\) everywhere along it. The only way to obtain a different world line connecting these same events, with all other things remaining equal, is to violate the above condition - i.e. introduce proper acceleration at some point, which leads to a world line that is shorter than the inertial one. Of course you can decide to vary initial conditions as well between observers, in which case they will trace out different inertial world lines between the same events - but then you are no longer comparing like for like.
  12. Or you can simply compare the geometric length of their world lines (given shared events to begin and end at), and be done with it
  13. I think it should also be noted that the notion of “gravitational potential” as we are used to it from Newtonian mechanics can only be meaningfully defined for specific types of spacetimes - at the very least they need to be stationary, spherically symmetric, and asymptotically flat. It is not a universally valid concept in GR.
  14. Time dilation is a fundamental feature of the world, it applies to all clocks irrespective of their internal make-up - be they mechanical, electromagnetic, atomic, light, or whatever else. It also applies to statistical processes such as the decay of elementary particles, which have no internal structure or mechanisms at all. Crucially, all other things being equal, the amount of time dilation is the same in all cases, regardless of what type of clock you use. This alone already shows that it is not an artefact of the clock mechanism. Atomic clocks are not light clocks. A pendulum clock is subject to time dilation, but it is also subject to external forces, so it is an unnecessarily complicated measuring device for this purpose. However, you can use the pendulum clock, if you know how to interpret the observed effects correctly. Locally in a small enough area, tidal effects can be neglected, and what we observe as “gravity” is entirely down to time dilation. So, it’s not that gravity causes time dilation, but gravity is time dilation - it’s curvature in the time direction. Newtonian tabletop mechanics aside, the theory of relativity is the most well-tested model in all of physics, and in perfect agreement to all experimental data within its domain of applicability. Length contraction can be directly observed in a number of different contexts, not just MM. Most notable here would be pretty much any particle accelerator experiment, atmospheric muons, the entire model of electrodynamics, undulator radiation, and so on. Note that kinematic time dilation and length contraction are just two aspects of the same phenomenon.
  15. Not even to mention that you’d be standing at an angle to the surface of a disk-shaped Earth, unless you are right at its center! I’d be a funny world.
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