edguy99 Posted December 18, 2016 Posted December 18, 2016 An Intuitive Model of a Particle Wave As a retired expert in the field of High Speed Digital Design I've had some problems with accepting the current model of a particle wave for light as shown below. The blue electric wave is perprndicular to the red magnetic wave and together they are said to be self-propagating waves by transferring energy between each other, but I'm unable to understand the mechaniism of how the energy can be transferred between perpendicular waves. Waves require two references, a ground reference in order to measure its amplitude and a clock reference in order to measure its phase but their are no such references for a wave propagating through spacetime ... This post is an extension of an earlier post meant to focus specifically on a photons "self energy" and how it moves through space. Specifically consider Landau & Lifshitz Vol. II. On page 108, the wave equation section talks about electromagnetic waves “in which the field depends only on one coordinate, say x (and on the time). Such waves are said to be plane”. Electromagnetic waves are ever changing “plane waves moving in the positive direction along the X axis”. In volume IV, page 5, Landau & Lifshitz continue, talking about Quantization of the Free Electromagnetic Field and on page 11, introducing photons: These formulae enable us to introduce the concept of radiation quanta or photons, which is fundamental throughout quantum electrodynamics. We may regard the free electromagnetic field as an ensemble of particles each with energy ω (= ħω) and momentum k (=nħω/c). The relationship between the photon energy and momentum is as it should be in relativistic mechanics for particles having zero rest-mass and moving with the velocity of light. … The polarization of the photon is analogous to the spin of other particles; …. It is easily seen that the whole of the mathematical formalism developed in §2 is fully in accordance with the representation of the electromagnetic field as an ensemble of photons; it is just the second quantization formalism, applied to the system of photons. … A photon is a plane wave travelling through space at the speed of light.
studiot Posted December 18, 2016 Posted December 18, 2016 Nice animation pic at the end, but it has a fatal flaw. The expanding cross and circle should surely be a rotating quadrant in which the H and E fields are positive?
edguy99 Posted December 18, 2016 Author Posted December 18, 2016 Nice animation pic at the end, but it has a fatal flaw. The expanding cross and circle should surely be a rotating quadrant in which the H and E fields are positive? Not sure I read this right, but certainly if the polarization was circular, you would want to see the quadrant rotate. This photon is vertically polarized.
studiot Posted December 18, 2016 Posted December 18, 2016 But the cross of vectors adds up to a constant big fat zero. Where does the pointing vector point from that cross?
edguy99 Posted December 18, 2016 Author Posted December 18, 2016 But the cross of vectors adds up to a constant big fat zero. Where does the pointing vector point from that cross? X-direction, forward in the motion of the photon.
studiot Posted December 18, 2016 Posted December 18, 2016 (edited) With zero value? Please think about what I am saying - I am unable to draw any diagrams at the moment to help. Your cross shows two pairs of equal and opposite vectors at every point, both of which cancel each other out or sum to zero. Consider only the E (or H ) component. When the E wave is positive there is nothing in the negative half plane, but you are showing a vector there that expands and contracts as does the real one in the positive half plane. Similarly when the E wave changes sign only the negative half plane is active. Edit I appreciate that your circle can be considered as a wavefront. But in that case it should not pulse in and out as that implies a longitudinal wave and light is a transverse wave. Instead a series of outwards spreading pulses that expanded and disappeared would be more appropriate. Please don't get me wrong. I think it is (would be) a great animation, if you can get the details correct. Edited December 19, 2016 by studiot
edguy99 Posted December 19, 2016 Author Posted December 19, 2016 Yes I am showing an expanding and contracting circular plane wave. Notice how when the E is positive, the plane wave is a very light color. When E is negative the plane wave is darker. This allows multiple photons to reinforce each other if they are in phase (dark with dark makes darker, light with light makes lighter), or to cancel each other out (light with dark makes a background grey) and gets me the full up/down cycle. Put another way, the size of the circle and the color of the circle match the amplitude of E and the orientation of E respectively. An animation of photon reinforcement and cancellation here.
studiot Posted December 19, 2016 Posted December 19, 2016 (edited) Please see my last edit. Yes the darker and lighter partly answer this but the diagram needs some accompanying explanation. I admit I did not notice the shading until you pointed it out, thank you. However my comment i8n pulsing still stands. Edited December 19, 2016 by studiot
edguy99 Posted December 19, 2016 Author Posted December 19, 2016 (edited) I would like to see your drawings, they would be illuminating. Where the fun come in, is to get a good model of the photon and then start to send groups of them around to see if you can model the actual properties seen. The "plane wave" model of the photon produces a pretty good Michelson Interferometer Edited December 19, 2016 by edguy99
studiot Posted December 19, 2016 Posted December 19, 2016 I am travelling today so I will be able to generate some diagrams in the next few days after I return home. The more I think about it the more tricky it becomes to generate a good animation but I really like the idea. It seems important to decide what aspect of the wave is to be displayed since you have both time and space to play with.
studiot Posted December 29, 2016 Posted December 29, 2016 OK so I agree you first figure is correctly oriented in that the wave is travelling in the correct direction for the E and B fields are to be phase as shown. So here is a sketch of the zy plane, preserving your orientation. The point is that the electric vector (shown solid) is the same at every point in the plane as is the magnetic vector and they form a rectangular grid pattern. The electric vectors are parallel to the z axis and the magnetic ones parallel to the y axis. I am worried your circle suggests a different variation, and I can't think of a way to prevent this.
swansont Posted January 2, 2017 Posted January 2, 2017 ! Moderator Note Tangential discussion has been split
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