studiot

Easy does it! Don't get photons and electrons mixed. I know it applies to both but it is confusing if you swop horses mid race.

I've said this before but I really like the way moderators are prepared to discuss procedure at SF. That said the current exchange raises an interesting issue. What is the position of the website vis a vis incorrect posts? A natural supposition of persons joining here or new to forums in general would be to expect the moderators to be experts to be looked up to and followed in technical matters. I certainly did when I first became involved in internet forums. Indeed the Architekt has just posted words to that effect in another thread. However a little thought reveals that this is an unrealistic expectation, especially considering the calibre of some (sometimes anonymous persons) posting. Moderators cannot be expert at everything. Can they be arbitrators in scientific squabbles? Perhaps those that are expert on the particular topic the view could indicate a post that is wrong ( or they think is wrong) or contrary to scientific concensus, but do it without 'enforcement'. Perhaps we should have a new thread to discuss this issue?

Your own good lady leader was a fellow chemist! Excellent point.

The energy in the system comes from the mechanical work moving the conductor. Don't forget that it is not any old movement in a magnetic field that counts it is movement perpendicular to the field. Movement parallel to the field has no effect.

Immortal I don't see how you can call my post speculative, or that it contradicts current concensus. I asked a polite question of your post, offered a friendly comment and then referred to the 2006 Nobel prize. do you intend to answer or avoid discussion?

Gosh have your tried typing fractional distillation into bigG? There's thousands of images.

Juanrga is correct in observing that a wave function is not a wave. However we should go further. I said earlier that some behaviour (eg reflection) can be modelled equally well by a stream of particles or by waves. Some behaviour is macroscopic ie the size of the 'particles' is orders of magnitude less than the scale of the phenomenon. My examples of lecher lines and cathode rays are like this. Both the ray and the lecher waves are of a scale that it matters not if the participating 'particles' are little wiggles (wavelets) or little balls.

Just to be clear why they are the same. Classically a particle (in any branch of physics) is defined as a very small unit or even the smallest unit in which all the property of interest can be considered to be concentrated or considered to act. Particle dimensions are often considered small compared to the dimensions in the problem under consideration. So saying there is a particle which 'carries' spin, mass, charge etc and we make up larger units from these, is in my view, the same thing.

Which is what I keep saying.

Compare 1) 2) (1) is pure particulate. Yes in the real world the electron emitter is of finite dimensions and you get statistical variations so the beam is of finite dimesions. But there are no wavelike effects. (2) is pure wave. Tthere are no beamlike effects Do you have any idea how difficult it is to agree (and disagree) with both yourself and Juanraga at the same time. I am become the one true quantum particle

If the points of a manifold don't exist, the manifold doesn't either. For functions defined on the manifold you can apply restrictions such as for X1 <0 f is not defined (not zero, not defined which is different)

Superposition has nothing to do with whether several fields (or other effect) may coexist in the same system. It does however have a great deal to do with the result of their interaction if they do.

I am getting confused as to which thread I said what in however I'm sure I said somewhere words to the effect that if you wish to appeal to (modern) mathematics for support and proof you have to remain within the conditions of validity. For manifolds each point either exists or it doesn't. You can't have points popping in and out of existence, just because you don't use them. Further you need to state whether you are using manifold in the general sense as just a collection of elements of a set. This definition possesses a very limited mathematical structure. Or in the specific sense of a topological manifold where you can take advantage of significant mathematical structure, up to and including calculus and beyond.

Read my description again, in post#64. They do in a beam tetrode or cathode ray tube. I even have an (old) textbook of electron ballistics pertinent to that era. However you may pass the same stream of electrons so that they form waves as in lecher lines. Consider the tetrode as one black box and the lines as another in series the electrons can pass through one black box as a particle and the next exhibiting wave properties. The boxes can also occur in the opposite sequence.

Yes this is the point (the link between time and existence) I am trying to get across but it is fundamentally at variance with the notion of a spacetime manifold.

Just as I described in my lecher lines, however they can move along definite trajectories note the key word assuming.

What does linearity have to do with it?

Using a,b, c as spatial coordinates was a mistake thanks. I have corrected it. All the letters are just numbers in some arbitrary coordinate system except c. Their values do not matter. They are not really variables. c is of course the necessary transformation constant to convert time to distance. What I am trying to explain is the notion that we cannot say "my computer no longer exists yesterday my computer exists today my computer does not exist tomorrow because time flows from past to future" In other words we cannot use 'the present' as a definition of existance within 'spacetime'. It already encompasses the past and future. Sorry if this is a bit rambling but I'm rushing.

Hello Alan, what did you make of my post#25? One of the consequences of the Minkowski spacetime continuum has profound implications for your last question which is bound up with existence. If we accept (for the moment) this view then take my computer. It has no existence on the moon. It is on earth. This may be obvious but consider it has space coordinates (a,b,c) (on earth) but not (m,n,p) on the moon. So what about time? Well it existed yesterday and today so it has time coordinates (y,t) So it has 4D coordinates (a,b,c,d,ct) and (a,b,c,d,cy) and everything in between. All this is a roundabout way of saying that in spacetime view time does not flow ie my computer does not cease existing yesterday because it exists today.

Yes indeed, quite so. +1 However there is more to it than that. I have been promoting the idea that it doesn't have to be one or the other but there is more to this than contained in the original post for Light and electricity possess four apparantly contradictory characteristics that 1)Can be explained either by waves or by particles 2)Can be explained only by waves 3)Can be explained only by particles 4)In addition they do not posses some characteristics attributable to particles or waves. All these four characteristics are present at all times. Bohr recognised this when he introduced 'complimentarity' which roughly explained means that the phenomenon cannot be explained by a series of either/or questions to which there are only yes/no answers. He called this type of reasoning classical logic and introduced non classical logic to account for activity. The actual activity observed depends upon the external conditions, not the quantum entities. These conditions 'extract' the characteristics of interest. So how does that play out with the original post? (1)&(2) No because it depends upon the external conditions as above. (3) Already answered by Swansont (4) Again depends upon conditions which is why I asked Juan about lecher lines and he avoided the issue. Consider a suitable source of electricity (at UHF) and pass it down a beam tetrode tube. You will get a beam of particles. That is what the tube does. The beam particle density does not vary appreciably and you may get a space charge effect. In effect the electrons rattle down the track like vehicles on a motorway. There are local clusters and but no wavelike structures appear.This is pure particulate behaviour. Now pass those same electrons from the tetrode down a lecher line. You will observe a periodic structure of voltage potential, sufficient to power a lightbulb at some points and zero at other. No particulate solution can lead to this behaviour. It is pure wave.

Immortal, I didn't understand the thrust of your post either. I think pmb was simply trying to ask which of the two options you posted you thought was the correct one. I don't think his reply was personalised. As regards to your extract from Dirac, isn't that view superceded by the modern idea of virtual particles?

Thank you, I am aware of the usual metric and its properties. I was just concerned that it is all too easy to transfer results from mathematics into physics and forget to transfer the conditions of validity. In particular you have to be very careful if you introduce i into the distance function because d cannot be imaginary or complex.

Talking of metrics here is an interesting one that declares that every point is the same distance from every other point. This is (almost) equivalent to the old geocentric view of the universe that projected all the universe onto the celestial sphere. For any two points r, s in 4D Minkowski space [math]d(r,s) = \left\{ \begin{array}{l} 1,\quad r \ne s \\ 0,\quad r = s \\ \end{array} \right\}[/math] Remember that for a metric function to be valid d must be non negative.

And using Juan's definitions the term particle and elementary particle correspond exactly to the classic definition of the term. La plus ca change la plus c'est la meme chose! +1

Well how about discussing my post#25 in the light of your views? It was a response to one of your earlier comments.