Freethought & Rationalism Archive

Lobstrosity · 08-02-2003, 03:07 PM

Quote:

Originally posted by Shadowy Man
The best way to think of it is terms of the magnitude of the momentum-energy four vector.

I quite agree. The momentum-energy four vector is quite a nifty little guy, as is the potential four vector. In fact all four vectors are cool--yay tensors.

Shadowy Man · 08-02-2003, 03:17 PM

Quote:

Originally posted by Lobstrosity
[B]I quite agree. The momentum-energy four vector is quite a nifty little guy, as is the potential four vector. In fact all four vectors are cool--yay tensors.

I remember learning how to derive compton scattering using four vectors! Very nifty... as my QM TA said "with four vectors, it pops right out!".

Chimp · 08-02-2003, 03:20 PM

Quote:

Originally posted by ex-xian
Was this supposed to futher your argument? All they're saying is consistent with what Lobstrosity. Instead of writing E=mc^2, with m understood to be the rest mass, now physicists are writing it as E=(gamma)mc^2. Also, the second part of that page explains the photons have to be massless for QED to work.

Mass is a form of energy:

http://math.ucr.edu/home/baez/physic...oton_mass.html

Quote:

In one sense, any definition is just a matter of convention. In practice, though, physicists now use this definition because it is much more convenient. The "relativistic mass" of an object is really just the same as its energy, and there isn't any reason to have another word for energy: "energy" is a perfectly good word. The mass of an object, though, is a fundamental and invariant property, and one for which we do need a word.

Obviously this photonic energy becomes localized, when it interacts with other types of particles.

QED deals with something called "renormalization" which deals with subtracting infinities and substituting the correct numbers in order to get usable results.

Why not explain localized energy as the wave-function collapse of Schrodinger's equation, where the localized energies are really standing waves?

The goal is to eliminate the infinities.

Chimp

Chimp · 08-02-2003, 04:49 PM

Quote:

Originally posted by Chimp

Mass "m" is a form of condensed space-time.

Condensation occurs a function of increasing density gradients.

Cotangent vectors.

Chimp · 08-02-2003, 09:45 PM

Photonic Energy

h is Planck's constant.

lambda is wavelength.

E^2 = [hc/lambda]^2 = (p^2)(c^2)

[h^2 c^2]/[lambda^2 c^2] = p^2

h/lambda = p

E^2 = m^2 c^4 + p^2 c^2

E^2/c^2 = m^2 c^2 + p^2

m = 0

E/c = p

Zero and infinity are really starting to bug me

tensorproduct · 08-03-2003, 06:45 AM

Quote:

Originally posted by Chimp
Quite the opposite, I say that there is no "absolute expansion" of space-time. There is no external frame of reference? that can relate to an expanding space-time.

Chimp

I don't mean to derail the discussion of 4-vectors (Grrr... I hate tensors), but Chimp what do you mean by a God's eye-view, I can't see how you would interpret that as anything but an external reference frame. I don't really see what this has to do with the expansion of space time.

Hang on, I think maybe I misunderstood the OP, I'll check.

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08-02-2003, 09:45 PM	#15
Chimp Regular Member Join Date: Dec 2002 Location: USA Posts: 376	Photonic Energy h is Planck's constant. lambda is wavelength. E^2 = [hc/lambda]^2 = (p^2)(c^2) [h^2 c^2]/[lambda^2 c^2] = p^2 h/lambda = p E^2 = m^2 c^4 + p^2 c^2 E^2/c^2 = m^2 c^2 + p^2 m = 0 E/c = p Zero and infinity are really starting to bug me

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