Mordred

This directly applies to \[t_b-t_a=\frac{r_{AB}}{v-c},,,\acute{t_a}-t_b\frac{r_{AB}}{v+c}\] given in section2 of the article were discussing. https://www.physics.umd.edu/courses/Phys606/spring_2011/einstein_electrodynamics_of_moving_bodies.pdf though in my case I added a stationary observer M

Oh boy so you didn't consider the interval length ct .That's obviously why you didn't understand what v-c and c+v were being used for. It is the interval length being applied not just the length of the train. Perhaps we should examine that first under Galilean relativity. take your train lets place Alice (A) at the rear Bob at the front (B) and have observer at mid point M. The train is moving at V relative to observer M. As both observers agree on the velocity of c then they will disagree on the Relative length given by the interval. Hence \(T_{A}= c-v_A\) and \(T_{B}=c+v_B\) This is directly applied using Galilean relativity and not SR, where v is much less than c. When v approaches c then the relativity effects of SR come into play. I'm going to stop here to make sure you can at least agree on this under Galilean relativity. as the interval is \(ct\) it has dimensionality of length hence using the interval time in replacement of length. There is no point going further if your not clear on Galilean relativity itself.

no it is not misguided to use the mathematics of a theory correctly when examining that theory. You don't make judgements on a theory without correctly applying its mathematics. Anyway I will first enjoy my morning coffee before showing how this is examined correctly under SR.

If you stop to listen for a change you might get the answer. ThoughI have had to ignore your insulting behavior far too many times in this thread that I really don't know why I even bother. After I eat and have my morning coffee I will show how SR does the electrodynamics of moving objects which is the essence of the examination your applying here. Of course he applies classical physics but you chose to ignore where he deviates from Galiliean relativity transforms.

You mention SR being wrong numerous tunes here but you didn't correctly applying SR. You didn't properly do its transforms so naturally you were not getting the correct answers. Instead you provided judgments and claims of it being in error by making errors in your examination. Secondly you specifically asked a question. "What is the function of c-v and c+v which I specifically answered.

Your examination of SR is wrong because you are not correctly applying the transforms of SR.

Your analysis for starters is missing a key ingredient with the Lorentz transforms. Where is the length contraction ? There are no rigid rods in SR Its late atm so I will look at this further tomorrow but I will answer one of your questions now. t The functions v-c and v+c applies to the observer on the embankment and directly to gaining relativity of simultaneaty. take two flashes of light emitted from A and B the relativity of simultaneity to an observer on the embankment can be preserved using the Doppler shift relation you posted though this may be a better form to see that if you contract ct (part of the Lorentz transform being the length contraction)by the factor v-c the ct interval length is also dilated to the other emitter via v+c to the observer midway between emitters A and B to the observer at M on the embankment. If you ignore the length contraction aspects you will of course get the wrong answers. I will have more time to go over this in more detail tomorrow

Lol not quite there yet

There is getting to be a decent number of papers on the application. I've been running across them quite often. I haven't heard of any tests done yet. Largely still in the proposal stages.

That is the more common proposed methods to apply quantum entanglement cryptology that I have encountered. At this point in time quantum cryptology is more of a speculative application. Thus far I haven't heard of any actual tests of its use.

In essence yes that a succinct way to describe it.

Oh now I'm a gang leader, did it never occur to you that everyone posting in this thread literally has their own opinion ? Anyways I would advise you to take into consideration the mod note in the post prior to this one. Quit wasting time with fruitless accusations

Think of it this way the applications in that paper don't describe encrypted messages. They describe means of detecting security breaches. It's something on the order of error detection methods used by computers today. Older examples being checksum or Cyclic redundancy checks.

Well said...+1

Not if you send numerous entangled photons. When Alice examines her photon stream Bob also examines his. If the photons are not opposite to one another on every pair then you would know you had corruption or a security breach Here is some of the encryption methods that have been suggested. https://arxiv.org/pdf/2003.07907 The easiest example the paper gives is through parametric down conversion. You will know the initial frequencies but once the beam passes through the beam splitter you wouldn't know which polarity is sent until you examine. From this you can apply the conservation laws and expect the opposite polarity at end. If you font have the opposite polarity at each end then you know something occurred to interfere with the signal.

Why wait ? It's very common to show what a model states with the relevant equations. Then apply the corrections or improvements. If you want to show you truly know what you talking about you might want to get the real meat of your analysis. Lol you have no idea how often we hear grandiose claims that A poster cannot mathematically support it would be a nice change to hear a good solid mathematical argument.

You know it seems to me your only argument is to judge the posters involved in this thread. You certainly haven't applied a single equation showing SR as being wrong.. So far the only mathematics has been posted by myself. SR and GR are mathematical models might help if you actually focused on the math for a change.

Really I know what mathematics works I certainly will not randomly believe your unproven claims over a well established and well tested theory. You have done absolutely nothing to prove SR is incorrect. I'm not about to willy nilly believe you simply because you claim your ideas are correct over well established models

No I grew tired of your antics. I showed mathematically what is described as the laws of physics are the same to all observers. If you cant figure out how invariant quantities apply and how the transforms apply to mathematically defining that postulate that isn't my hangup. Hint it also applies to conservation laws which also directly apply to invariant quantities.. Those details were further shown in the link I provided by the way. Tell me something does not the fact that SR has length contraction and time dilation not mean that this doesn't describe curved spacetime ? Spacetime curvature occurs when you have both

Don't believe the physics of SR stopped in 1905. Work continued on SR Long after that date. The term geodesic also existed prior to both SR and GR. For that matter

Did you not catch the part where I mentioned in either form of relativity? 3 forms Gallilean, SR, GR. Though geodesics certainly do apply in SR as well. Geodesics don't exist in just curved spacetime they also exist in flat spacetime. Would you like the Christoffel connections for flat spacetime? Or are you not aware the the line element describes the worldline of a metric. Given by ds^2 for separation distance ? A worldline is a type of geodesic

Great glad to hear that. Then you should have no problem mathematically showing where SR is incorrect.

Well quite frankly if you don't understand the very basis of relativity, that it is a model that describes particle kinematics which entails addition of velocities under graph aka coordinate system. in essence the space or spacetime paths. Which is described by geodesics. Then its pointless to go any further. That is precisely what Relativity in either form is designed to do.

what do you think the transformation are for ? they directly apply to transforming from one geometry to the other. That is the very essence of the laws of physics are the same in all inertial frames of reference. That includes velocities from 0 to c. Regardless of geometry or regardless of observer all observers will agree on invariant quantities. c itself is an example of an invariant quantity. so to maintain that invariance you need the relevant transformation rules. Here this will save me tons of having to type in the basis of the kinematics and how it relates to the addition of velocities. It will start with the basics of Galilean relativity to Lorentz. Including highlighting Covariance and invariants. https://www.seas.upenn.edu/~amyers/SpecRel.pdf in particular note section 8 with regards to c Maxwell equations starting with "8. Electrodynamics and Lorentz symmetry" The article highlights the essence of invariant quantities (an invariant quantity is the same to all observers) under both Galilean relativity and SR,GR.

So you want me to teach you basic calculus is that it? Did you not learn basic kinematics in school ? Why should I waste time teaching you that if your here questioning relativity itself ? I showed you how the transforms preserves those lessons you should have been taught in high school physics If you dont understand basic kinematics under geometry treatment in Euclidean level mathematics You should start there. Prior to trying to understand and question SR and GR. Those basic lessons are essential.