Recent content by TerryW

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    MTW Ex 25.20 - Dynamic Phase Diagram

    Hi Tony, You really are a star! Thanks. TerryW
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    MTW Ex 25.20 - Dynamic Phase Diagram

    Hi TSny I've now figured out the reasoning behind equations 28 & 29 in Box 25.4 - I just have one issue left which I haven't been able to resolve. It comes from the picture you posted in #6 of the orbit of the particle, which is a line that is normal to the wavefronts it crosses. I thought it...
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    MTW Ex 25.20 - Dynamic Phase Diagram

    Sorry, that was a bit sloppy on my part! I feel that there isn't much else to be extracted from this problem - but I have just one question I'm going to look at before I move on. That is: Why does ##\frac {\partial{ \tilde S}}{\partial{ \tilde L}}## produce 'the shape of the orbit' and why is...
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    MTW Ex 25.20 - Dynamic Phase Diagram

    Hi TSny I've checked my workings and have found the rogue factor of 4! I had also been doing some work to reconcile the differences between my computed integral and the analytic integral and was having a problem explaining why the analytic integral was greater than the computed integral...
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    MTW Ex 25.20 - Dynamic Phase Diagram

    I'm fairly confident about the factor 4 in my expression. The results from using this expression for ##\phi## with the factor 4 are very close to my original computed values. Without the factor 4, the discrepancy would be problematic. I'll see if I can wrangle my expression for ##\phi## into...
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    MTW Ex 25.20 - Dynamic Phase Diagram

    Hi TSny I think I've cracked it now. Equation 25.42, for the special values of ##\tilde E= 1##, ##L \dagger = 4##, has the 'analytic' solution: ##\phi = -4 \sqrt 8 ln(tan(\frac{1}{2}arcos(2 \sqrt(\frac{M}{r}))))## I've used my spreadsheet to produce the orbits for the computed integral and...
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    MTW Ex 25.20 - Dynamic Phase Diagram

    I've abandoned the attempt to get a path using the 'interference' method. There is a problem creating curves for values of ##\tilde E < 0## because the particle ends up at distances r/M >4, they don't have the energy to scale the full height of the potential, so the interesting part of the curve...
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    MTW Ex 25.20 - Dynamic Phase Diagram

    Thanks for doing this. I'll carry on with my attempt to get the path by the 'interference' method.
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    MTW Ex 25.20 - Dynamic Phase Diagram

    Hi TNsy I'm still working on this, albeit slowly. (It's Spring so I need to get my vegetable seedlings going for one thing) I have worked through (27) and derived the same answer as you (don't know why the square root signs have disappeared in the quote) but that immediately gave me a problem...
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    MTW Ex 25.20 - Dynamic Phase Diagram

    I've had my think and run my model for a value of r/2M = 163 and found that my curve spirals 5+ times before it reaches r/2M = 4. I've attached a screenshot of my initial data. I assume that the result of the integral is an angle given in radians. I think that the spiralling arises because even...
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    MTW Ex 25.20 - Dynamic Phase Diagram

    Our different plots are not exactly alike - I'll have a think and get back to you. I'll see if I can do something to replicate your generation of the trajectory. I really like what you have done! Terry
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    MTW Ex 25.20 - Dynamic Phase Diagram

    My spreadsheet is now working well and I have plotted the orbit of a particle starting the integral at r/M = 193. I figured out a way to get Excel to produce a radial plot using some macros - I just haven't been able to get rid of the line joining the beginning of one of the orbit segments and...
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    MTW Ex 25.20 - Dynamic Phase Diagram

    Hi TSny Lovely to hear from you again. Hope you are keeping well. I've used my spreadsheet to do the integration and then I hit on the idea of plotting my results on a radar chart where the result of the integration is the angle and the path is rendered by the value of r/2M plotted on the...
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    MTW Ex 25.20 - Dynamic Phase Diagram

    I am attempting to construct the locus in the r,θ diagram of points of constant dynamic phase S~(t,θ) for t=0 and for values ofL~=4M,E~=1 I begin with Equation (27) in Box 25.4 which is: ##\tilde S = - \tilde E t +\tilde L \theta ## ##+ \int^r [\tilde E^2 - (1-\frac{2M}{r})(1+\frac{\tilde...
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    Problem with dimensionless quantities in an equation requiring M^2 (Super Hamiltonian Formulation for Geodesic Motion)

    I actually feel that you’ve helped me a great deal with this problem and the exchange has improved my understanding of what parameterisation is all about and that ##\frac{d}{d\lambda}## is something more abstract than classical momentum. So you’ve most certainly helped me more than you think you...
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