Markus Hanke

I am genuinely of the opinion that all my replies were direct responses to something you posted, and didn’t ignore the salient points; and yes, I had to repeat myself - several times over - because there is only one mechanism explaining these observations, so there are only so many responses one can possibly give. How about the colliding gold ions at the RHIC, which I referenced earlier? I personally feel that’s an even better example, because the experiment can be repeated in a controlled manner in a lab, and contains fewer unpredictable variables.

The very title of the thread already gave it away right from the start, but I had been hoping that explaining the theory plus listing experimental evidence might have had some effect at least. Sadly though, at this point the best term I can think of to describe this thread is ‘sealioning’.

This appears to be better suited for a new, dedicated thread; it doesn’t quite fit into this discussion.

This isn’t a contradiction at all, because these are different observers performing a measurement the outcome of which is observer-dependent, since they’re measuring something that isn’t intrinsic to the train, but describes only their relationship to it. It seems to me that we are just repeating both question and answer over and over again, to no avail at all it seems. So let me ask you this - are you actually interested in the explanation, or have you made up your mind already that relativity must be wrong? Just be honest.

The invariance of c is a direct consequence of Lorentz invariance, so any experiment testing this symmetry would verify that finding. There is a large body of such experimental tests. But you don’t even need any reference to relativity for this, because it also follows directly from Maxwell’s equations - the propagation velocity of light in vacuum depends only on vacuum permittivity and permeability, and nothing else. So it is naturally invariant between frames, since these are fundamental constants. And I think we can all agree that Maxwell is not under contention.

The particles are one meter apart as seen from a specific frame of reference. A different observer will measure a different distance. All observers are right, in their own frames. A specific Length is thus a relational property, and not somehow intrinsic to the object. I guess-timate that this has been pointed out now at least ~10 times or so, in different ways be different posters.

I’m an amateur science enthusiast; I’m also a Buddhist monk. In principle you are right - the issue should not be of concern in Buddhism. In practice though it depends on which of the many schools you look at, and even who you are talking to. Many Buddhists very much do have various supernatural elements in their world view, or interpret some of the central ideas in supernatural ways; scriptural literalism and fundamentalism sadly also happens. In fact, those Buddhists who don’t do any of those things are very much in the minority. I personally see no issue (or else I wouldn’t be on here), since my ‘personal Buddhism’ does not contradict any scientific findings that I am aware of, and vice versa - they are very much dealing with two separate domains of enquiry, both of which are limited in their applicability.

Yes, of course. But what I meant here isn’t the maximum correlation (which is always 1 of course), but how it is distributed as a function of detector angle in the classical Bell experiment (graph taken from Wiki). You can see the quantum correlation is stronger than classical correlation (local realism):

Not when they are hitting the screen - they behave like particles there. They also behave like particles in other circumstances, such as eg the photoelectric effect. Apart from this being inconsistent with the specific experiment linked to by swansont, it also runs counter to double-slit type experiments done with quantum objects other than light, which don’t exhibit the property of polarisation. As already pointed out numerous times, the observed effects are independent of the nature of the quantum object - they happen with photons, but also with electrons, C60 molecules, or any other quantum object. The common denominator is always the availability of which-path information.

I must admit I’m confused about the last few comments. Entanglement is a correlation between measurement outcomes, in the sense that the multi-partite system is non-separable. Knowing whether a system is entangled requires one to take measurements on all parts, and then bring the results together and compare them. The only thing special about quantum entanglement is that the correlation is stronger than classically allowed.

I don’t think this is a useful comment - you cannot know to what degree people here are really familiar with quantum physics. Some of us have studied this stuff in depth and for a long time, and know that there’s a much wider context to be considered than a single, specific experimental setup.

No - there is only one train, but many observers. The property of “length” is not intrinsic to the train - instead, it describes a relationship between the train and a specific observer.

I agree, the difference is in fact huge. What I meant by my comment is that the definitions may sound similar on the surface, to those who don’t think about them more carefully.

I think this would simply be because most people on the Internet aren’t themselves academics, and thus may not immediately grasp the difference between these - superficially similar-sounding - definitions.

I’d like to throw in two more notions, if I may. Firstly, a “negative” belief in the absence or falsity of something is itself a belief, same as believing “in” something. And before anyone says it - no, I do not come from any kind of theistic angle. It’s a general notion. Secondly, the concept of epistemic responsibility seems pertinent to the discussion. Basically it means we have a moral responsibility to critically evaluate the beliefs we hold in terms of available data. Are these beliefs justifiable? This goes equally for positive and negative beliefs.

It depends on the observer of course - there will exist an observer in whose frame it is 1m, and there will also exist an observer in whose frame it is 100m. All of these observers are right - but only in their own frames. The length of the train is thus not an intrinsic property of it, any more than eg. its speed or kinetic energy. It is meaningful only in relation to a specific observer measuring it, so asking about its “real” length is meaningless. There are indeed quantities that all observers in spacetime agree on (tensors and invariants), but length is not one of them; it’s strictly a quantity that describes a relationship to a given observer only.

Yes, and some religions do not have any concept of God, in the theistic sense.

Of course. The problem here though is that a duality is not a contradiction. You are making a category mistake. For example, consider the below picture, which is a rectangle-circle duality; there’s no contradiction, because the object in question is neither a rectangle nor a circle, yet contains aspects of both. Likewise with wave-particle duality - quantum objects (any type, not just electrons) sometimes exhibit particle-like behaviour, and sometimes wave-like behaviour, depending on how you look at them - while at the same time ‘being’ neither of those things. They are a separate ontological category to classical waves and particles. Which information is accessible depends on the observer.

This is not directly related to relativity of simultaneity, since in the twin experiment, the reason for differential ageing is that part of the travelling twin’s journey isn’t inertial, so the symmetry between frames breaks down. That’s a different mechanism. You can see differential ageing in particle accelerators when using ion beams - fast beams spread slower (Coulomb forces) than slow beams, in the lab frame. A second ago on the distant observer’s clock; at t=0 at the place of the event; maybe a year in the future for yet another observer. That’s precisely the point - there is no universal time frame. It depends on the observer, and their relationships. Remember this is about simultaneity. And this is all correctly accounted for in the math, as pointed out.

May I just throw in here that religion does not necessarily equal theism. Not everyone who identifies with a religion believes in a creator deity.

An ‘observer’ in quantum physics is any means by which some of the available information may be accessed. In this case, it is simply a screen at a certain location. The point is, an ‘observer’ does not need to be sentient or conscious. However, different types of observers may provide access to different information, so they do have a role to play in that sense. This isn’t a causal relationship though.

No it doesn’t, because the geometric length of a world line in spacetime is not identical to an observer’s measurement of spatial length - as I have pointed out in my post. You are correct of course, my use of terminology was sloppy. Thanks for pointing it out! Length contraction - like time dilation - has real-world physical consequences that are directly detectable, so the very notion of it being illusory isn’t tenable. - The classic example being of course atmospheric muons - Another classic example is the change in interaction cross section of relativistically colliding gold ions at the RHIC - Magnetic forces on test particles passing currents at relativistic speeds (Purcell, Electricity and Magnetism) - Free electron lasers - Flux quanta in Josephson Tunnel Junctions - Changes in ionisation energy levels for relativistically moving particles Among many others. None of these things are ‘illusions’, these are very real, directly detectable phenomena that are direct consequences of relativistic physics; some of these are relevant to engineering applications.

In SR, when a frame is said to be ‘in motion’ with respect to another frame, that means it is rotated about a hyperbolic angle in Minkowski spacetime, again with respect to the coordinate system of the reference frame. This is why speed can be expressed as an angle, called rapidity. This is just what Lorentz transformations do - they deliver a rotation, plus a boost (which is irrelevant here). Measurements of length are the projection of the world line onto the spatial axis of the associated coordinate system; measurements of duration are projections onto the time axis. Now, if you rotate the coordinate system about some angle (=relative motion!), then this will quite naturally alter the magnitude of these projections. This is why we see kinematic time dilation and length contraction. Note that the geometric length of the world line itself does not change - all observers agree on it. They are just looking at the same thing from a different angle in spacetime - quite literally so. Note also that the rotation is a hyperbolic one in Minkowski spacetime, which is not quite the same as a Cartesian rotation in Euclidean space. None of this is in any way in conflict with the ‘block universe’ picture, nor are there any contradictions anywhere. It’s just elementary hyperbolic geometry.

That’s not quite right - it’s about the availability of which-way information, not its being known. If such information is accessible, even just in principle, then no interference is seen. This is irrespective of whether or not there is a conscious observer who actually knows the information, so the observer does not alter the outcome of the experiment in a causal-mechanical sense. Ultimately the issue is information-theoretic - some degrees of freedom of the entire (!) spacetime region representing the experimental setup become entangled with some degrees of freedom of the observer, wherein ‘observer’ just means any part of the environment external to the double slit (no sentience, sapience, or intentionality is necessary - just a screen is enough). It is precisely that - which degrees of freedom become entangled - that determine what ‘mix’ of particle and wave aspects of the quantum system becomes apparent to the observer. If you put your observer (=detector) directly into a slit, you end up with a different set of degrees of freedom as opposed to when the screen is far away, so it is not surprising that the pattern on the screen is not the same. You’re simply dealing with different information.

That’s not true - relativity of simultaneity is explicitly about distant simultaneity, ie events and observers at different spatial coordinates. Within the mathematical treatment, this spatial separation as well as the finite propagation speed of light are explicitly accounted for within the necessary Lorentz transformation.