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Hello
I am trying to understand how one sees that particles are propagated forward in time and antiparticles propagated backward in time.
http://www.phys.uAlberta.ca/~gingrich/phys512/latex2html/node77.html
Eq 6.75 and 6.76 are the sources for my confusion. The text says "We see that [itex]S_F(x^\prime-x)[/itex] carries the positive-energy solutions [itex]\psi^{(+)}[/itex] forward in time and the negative-energy ones [itex]\psi^{(-)}[/itex] backward in time "
If t' > t, then positive freq. are prop. from t to t' and then the step function for the neg. freq. sol.'s is zero and hence no propagation. The negative freq. are propagated only if t' < t
So let's say we start at t = 5. Then pos. freq can be propagated to t > 5 and then neg. freq to t < 5.
Is this the correct observation one should make? Or is it the minus sign? Since the text says "The minus sign in the second equation results from the difference of the direction of propagation in time between (6.75) and (6.76). "
This is why I get lost I think, the text stresses that minus sign in some way I can't really appreciate
I am trying to understand how one sees that particles are propagated forward in time and antiparticles propagated backward in time.
http://www.phys.uAlberta.ca/~gingrich/phys512/latex2html/node77.html
Eq 6.75 and 6.76 are the sources for my confusion. The text says "We see that [itex]S_F(x^\prime-x)[/itex] carries the positive-energy solutions [itex]\psi^{(+)}[/itex] forward in time and the negative-energy ones [itex]\psi^{(-)}[/itex] backward in time "
If t' > t, then positive freq. are prop. from t to t' and then the step function for the neg. freq. sol.'s is zero and hence no propagation. The negative freq. are propagated only if t' < t
So let's say we start at t = 5. Then pos. freq can be propagated to t > 5 and then neg. freq to t < 5.
Is this the correct observation one should make? Or is it the minus sign? Since the text says "The minus sign in the second equation results from the difference of the direction of propagation in time between (6.75) and (6.76). "
This is why I get lost I think, the text stresses that minus sign in some way I can't really appreciate
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