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Everything posted by pmb

  1. Check your PM. I sent you a treatment of the Wave-Particle Duality. You should find it very helpful. Those kinds of thing belong in the forum where people post speculations, not in the physics forums.
  2. Yes. Absolutely. A CRT is a macroscopic device and as such doesn't require the principles of quantum mechanics to construct it.
  3. Note: A photon doesn't have a 4-velocity. A 4-vlocity requires dividing by a proper time interval on the photons world line and that's always zero, hence there's no 4-velocity for photons (or any other luxon).
  4. Example: Almost every QM text that I have explains the wave-particle duality and what it means. This is a well-defined and unbiversally accepted phenomena with endles reams of data to sup[port it. Yet there are places where people claim that there is no such thing as a wave-particle duality. When I see people say that I neg-rep them. Then there's relativistic mass. People claim that nobody uses it and yet the majority of current relavity textbooks uses the concept. So when I see people claim that nobody uses it I neg-rep them. Its always something which I have a lot of evidence which demonstrates that they're wrong. There was a time that someone was trying to convince me that a photon had a 4-velocity, which it doesn't. I would have neg repper them if there was a system in place to do that. But its all objective things that I'm referring to. Not mere disagreement over something.
  5. I appologize for being unclear. I'm very cautious whn I say things like that because, at least in my eyes, its quite tricky. For example: What exactly is an experimental set up? If I have 10,000 doub;e slit experiments set up each of which only one particle goes through. In each case the electron is localized when it hits the screen, where the position is then recorded. In each experiment there is no wave property other than the wave being used to prdict where the electron will be. The ensemble of experimental set ups shows that there is intereference as an enemble but there's no way that it can be said that electrons are interfering with each other. Do you see why I'm cautious?
  6. Here's how I used to use it. Reasons for a + rep (1) Funny post (2) Good physics (3) Beautiful way of saying something (4) When someone refrains from lashing out (5) Positive emotions Reason for a - rep (1) When someone intults someone else (2) A veiled attempt at insulting someone (3) Negative emotions (4) When someone lashes out (5) Angry comments (6) Arrogance (7) Saying things which goes against textbook physics If nobody has a problem with that then I'd feel comfortable using it again. Anybody?
  7. Nobody used a personal attack against anybody else in this thread. We disagree with you. I scanned and PMd the section of the wave-particle duality from my graduate text on quantum mechanics to the people in this thread. They already know what its all about. Historical Note: It was Author Eddington who coined the term wavicle The following is, in essence, what the wave-particle duality is all about. Simply put: All experiments on diffraction and interference effecs with articles show that a definite wavelength is associated with partilces of a a given momentum. That's the very definition of wave-particle duality. This is just straight textbook quantum mechanics. Has C. Ohanian describes it as follows in his text Modern Physics - 2nd Ed. on page 147 This is the definition of what the term wave-particle duality means. Anyh atempt to claim otherwise is just plain wrong.
  8. That doesn't downplay the concept of time. Einstein's field quations are about defining a gravitational field. That field may vary with time and free particles which are in the field change their position as a function of time. At this point in time I'm going to back out and leave it be. I've said all I've had to say and anything more would just be repetition. We'll just have to agree to disagree my friend.
  9. I disagree. First off its the context which tells you what the manifold is. Second, quite often when one uses the term manifold its because they want to emphasize that its not physical space.
  10. Consider it done. A beam of electrons is not a trajedctory. If it was possible for an electron to follow a classical trajectory precisely then the curve would have a width of zero. The beam width of an eletron beam is very very very far from being a partilce trajectory. If someone is talking about such a trajectorey thn they are ignoring quantumn effects. That's done quite often in classical mechanics but never in quantum mechanics.
  11. You can't. Different people have their own ideas of what time is all about. I explained mine already when I used the analog with the electric field. I strongly disagree. Consider the Lorentz force equation [math]\frac{dp^{\alpha} }{d\tau} = \frac{q}{c} F^{\alpha\beta} U_{\beta}[/math] That has time explicitly in it. Worldlines are a set of variables which determines a curve. One of those variables is time. Yes. I don't think of space as beng a degree of freedom. The number of parameters required to uniquely specify the system is called the number of degrees of freedom. The system that those numbers are decribing isn't a degree of freedom.
  12. I believe that if you were to think of it simple as a set then you'd bve safe. Hilbert space is a set of functions. I'm just trying to get ytou to understand the difference between physical space a mathematical space. When I was in college studying to become a physicist I saw that if I took manth courses instead of basket weaving I could have a second majopr in math. And with physics you can't have enough math. That's why I'm familiar with mathematical spaces.
  13. I think you may have misinterpreted that quote. Electrons cannot follow definite trajectories. That's what it was saying, i.e. its not a particle in the sense that it can move along definite trajectories.
  14. I'm curious about something so please bear with me. Have you never heard the term space used in any other sense than "place inside a room"? For example when you hear the term Hilbert Space as being a function space, what did the term space mean to you? Wikipedia defines Space in the mathematical sense as follows http://en.wikipedia.org/wiki/Space_(mathematics)
  15. Yes. And as I've been trying to say is that time is a dimension of the spacetime manifold. A manifold is a collection of elements which satisfies certain properties. It is a space in the mathematical sense of the term, not as space as in "position of something inside my living room." It's a space in the abstract sense as I've given examples for in the post above. I'm glad we got that cleared up.
  16. Let's get something straight. The wave-particle duality is no a myth. In fact its a subject that you can find defined and described in all textbooks on quantum mechanics. It has a very precise meaning which is defined here http://en.wikipedia.org/wiki/Wave%E2%80%93particle_duality. I have a graduate level quantum mechanics text called Principles of Quantum mechanics - 2nd Ed. by R. Shanmkar. From page 113 That is the precise meaning of wave-particle duality.
  17. I don't understand what you mean by this. The letter "y" usually refers to a spatial variable, not a temporal one. And here you have two variables when a time coorinate only uses one. So what does (y, t) mean? Again, you seem to be using a spatial coordinat, y, where a temporal one is usually used. Time does pertain to your computer though. I don't know why you say that in spacetime view time does not flow . Can you elaborate for me? We can record moments in time. Its just that being human we don't experience moments in time very well. But its not a paradox in any sense of the term.
  18. I only mentioned it because I was criticized for my usage of the reputation system. I didn't appreciate that. Request: This is directed to the person who criticized me. Please don't reveal who you are in open forum. I don't want to drag anybody into this. The other person made the mistake of revealing their identity so please don't do the same thing. Thank you.
  19. The first five points were about the subject of the thread but had nothing to do with the argument. In the opening post I referred to it as an ad hominem. Later on, in post #20, I quoted the definition of it from my text on critical thinking and in that definition it stated that personal attacl was just another name for ad homine, i.e. that they're synonyms. Later, in post #24, swansont started to question the fact that that they're synonyms. I explained why it wasn't and it took on a life of its own after that. I don't know why people are so interested whethher these two terms are ad hominems. They just keep asking me questions and I keep answerig them. I lost interest in this a very long time ago. People still continue telling me I'm wrong so I continue to explain it to them. If you want to know why they keep bringing it up you'll have to ask them. I'm bored so I don't mind answering them.
  20. To whom are you referring?
  21. I disagree, of course. The definition you just provided is in essense identical to the one in my text. In fact I've used this one myself in this thread. Your definition states that for somethng to be a personal atack it must be mopre than just an abusive remark. In order to be a personal attack it muist be given instead of elements of an argument against the other persons claim. You're using it as being synoymous with abusive remark which is an incorrect usage. What you just claimed here is contrary to the definition you just gave in that the insul must be used instead of an arguement. An insult doesn't have to pertain to someones arguement like a personal attack does. And that's according to the definition you yourself just quoted.
  22. Edit: Sorry. I think I was asleep when I wrote that!
  23. I dissagree in the sense that this is a topic in the philosophy of science. We're discussing the definitions of t basic terms used in science. Definitions don't need to be falsifiable, oinly hyopotheses do. E.g. if I said that the electric field is defined as force per unit mass then it can't be falsified, but that doesn't mean that its wrong. The same with the concept of time.
  24. The Minkoski metric is defined as the tensor g in [math]dX*dX = g_{\alpha\beta}dx^{\alpha}dx^{\beta}[/math] where g = diag(1, -1, -1, -1) or [math]dX*dX = ds^2 = c^2dt^2 - dx^2 - dy^2 - dz^2[/math] This metric does not say that every point is the same distance from every other point though. This is the metric used in flat spacetime. In the early history of relativity they used to use ict as the temporal component of an event, not just ct. That's what Aethelwulf was talking about when he referred to the imaginary space dimension. But the term "space" as used here is in the abstract sense as I've explained about in quite a lot of detail. Nobody uses that nowadays though so that point is moot.
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