Mike Helland
Jun28-05, 09:22 AM
<jabberwocky><div class="vbmenu_control"><a href="jabberwocky:;" onClick="newWindow=window.open('','usenetCode','toolbar=no, location=no,scrollbars=yes,resizable=yes,status=no ,width=650,height=400'); newWindow.document.write('<HTML><HEAD><TITLE>Usenet ASCII</TITLE></HEAD><BODY topmargin=0 leftmargin=0 BGCOLOR=#F1F1F1><table border=0 width=625><td bgcolor=midnightblue><font color=#F1F1F1>This Usenet message\'s original ASCII form: </font></td></tr><tr><td width=449><br><br><font face=courier><UL><PRE>Igor Khavkine wrote:\n> On 2005-06-21, Mike Helland <mobydikc@gmail.com> wrote:\n> > Igor Khavkine wrote:\n>\n> >> You confuse measurable prediction with interpretation of a calculation.\n> >> A contribution to the path integral that involves a path where the\n> >> photon travels faster than c is an interpretation of a particular\n> >> complex number. It is not a prediction, since, as I\'ve mentioned, these\n> >> individual paths are not observable.\n> >\n> > You\'re saying that:\n> >\n> > 1. QED predicts the probability of an event based on the possibility\n> > that a photon has traveled at a non-45 degree angle in a Feynman\n> > diagram.\n>\n> This makes little sense to me, so I can\'t admit to having said any of\n> it. Are you talking about the 45-degree angle between the time axis and\n> the light cone?\n\nNo, in a Feynman diagram with a single axis for space a 45 degree angle\ntypically (or so I thought) represents a particle traveling at c.\n\n\n<snip>\n> > 2. But even though it makes its the prediction based on such\n> > possibilities, the fact that these possibilities are impossible\n> > according to SR doesn\'t matter, because the probablistic nature of QED\n> > predictions doesn\'t tell us precisely which possible Feynman diagram\n> > represents the path of particles leading up to the event.\n>\n> This is no more than a play on words. You say that "probabilities" come\n> from "possibilities". I say that "probabilities" come from calculations.\n> The calculations, being scribbles on paper or bits in computer memory,\n> don\'t need interpretation since they are not measurable, only their\n> results do.\n\nThe scribbles are all the possible things that might happen between the\ninitial conditions and the end result.\n\nYou can bet your *** they are given interpretation, otherwise we would\nnever talk about absorbed/emitted photons, spontanous\nparticle/anti-particle creation and annhilation, or the uncertainty\nrelationship between energy and time.\n\nAll of those things come from the inside of a Feynman diagram as far as\nI know.\n\nWhen faced with the fact that in order to wind up at the correct\ncalculations we need to consider the photon travelling faster and\nslower than c, you can believe as hard as you want that Special\nRelativity hasn\'t been violated. It\'s rather easy to do, actually,\nsince noone else is willing to point out the inconsistency. So you\'ve\ngot strength in numbers\n\nBut if anyone here is working on the next generation of solutions to\nquantum gravity, that inconsistency is a powerful clue, in my opinion.\n\n</UL></PRE></font></td></tr></table></BODY><HTML>');"> <IMG SRC=/images/buttons/ip.gif BORDER=0 ALIGN=CENTER ALT="View this Usenet post in original ASCII form"> View this Usenet post in original ASCII form </a></div><P></jabberwocky>Igor Khavkine wrote:
> On 2005-06-21, Mike Helland <mobydikc@gmail.com> wrote:
> > Igor Khavkine wrote:
>
> >> You confuse measurable prediction with interpretation of a calculation.
> >> A contribution to the path integral that involves a path where the
> >> photon travels faster than c is an interpretation of a particular
> >> complex number. It is not a prediction, since, as I've mentioned, these
> >> individual paths are not observable.
> >
> > You're saying that:
> >
> > 1. QED predicts the probability of an event based on the possibility
> > that a photon has traveled at a non-45 degree angle in a Feynman
> > diagram.
>
> This makes little sense to me, so I can't admit to having said any of
> it. Are you talking about the 45-degree angle between the time axis and
> the light cone?
No, in a Feynman diagram with a single axis for space a 45 degree angle
typically (or so I thought) represents a particle traveling at c.
<snip>
> > 2. But even though it makes its the prediction based on such
> > possibilities, the fact that these possibilities are impossible
> > according to SR doesn't matter, because the probablistic nature of QED
> > predictions doesn't tell us precisely which possible Feynman diagram
> > represents the path of particles leading up to the event.
>
> This is no more than a play on words. You say that "probabilities" come
> from "possibilities". I say that "probabilities" come from calculations.
> The calculations, being scribbles on paper or bits in computer memory,
> don't need interpretation since they are not measurable, only their
> results do.
The scribbles are all the possible things that might happen between the
initial conditions and the end result.
You can bet your *** they are given interpretation, otherwise we would
never talk about absorbed/emitted photons, spontanous
particle/anti-particle creation and annhilation, or the uncertainty
relationship between energy and time.
All of those things come from the inside of a Feynman diagram as far as
I know.
When faced with the fact that in order to wind up at the correct
calculations we need to consider the photon travelling faster and
slower than c, you can believe as hard as you want that Special
Relativity hasn't been violated. It's rather easy to do, actually,
since noone else is willing to point out the inconsistency. So you've
got strength in numbers
But if anyone here is working on the next generation of solutions to
quantum gravity, that inconsistency is a powerful clue, in my opinion.
> On 2005-06-21, Mike Helland <mobydikc@gmail.com> wrote:
> > Igor Khavkine wrote:
>
> >> You confuse measurable prediction with interpretation of a calculation.
> >> A contribution to the path integral that involves a path where the
> >> photon travels faster than c is an interpretation of a particular
> >> complex number. It is not a prediction, since, as I've mentioned, these
> >> individual paths are not observable.
> >
> > You're saying that:
> >
> > 1. QED predicts the probability of an event based on the possibility
> > that a photon has traveled at a non-45 degree angle in a Feynman
> > diagram.
>
> This makes little sense to me, so I can't admit to having said any of
> it. Are you talking about the 45-degree angle between the time axis and
> the light cone?
No, in a Feynman diagram with a single axis for space a 45 degree angle
typically (or so I thought) represents a particle traveling at c.
<snip>
> > 2. But even though it makes its the prediction based on such
> > possibilities, the fact that these possibilities are impossible
> > according to SR doesn't matter, because the probablistic nature of QED
> > predictions doesn't tell us precisely which possible Feynman diagram
> > represents the path of particles leading up to the event.
>
> This is no more than a play on words. You say that "probabilities" come
> from "possibilities". I say that "probabilities" come from calculations.
> The calculations, being scribbles on paper or bits in computer memory,
> don't need interpretation since they are not measurable, only their
> results do.
The scribbles are all the possible things that might happen between the
initial conditions and the end result.
You can bet your *** they are given interpretation, otherwise we would
never talk about absorbed/emitted photons, spontanous
particle/anti-particle creation and annhilation, or the uncertainty
relationship between energy and time.
All of those things come from the inside of a Feynman diagram as far as
I know.
When faced with the fact that in order to wind up at the correct
calculations we need to consider the photon travelling faster and
slower than c, you can believe as hard as you want that Special
Relativity hasn't been violated. It's rather easy to do, actually,
since noone else is willing to point out the inconsistency. So you've
got strength in numbers
But if anyone here is working on the next generation of solutions to
quantum gravity, that inconsistency is a powerful clue, in my opinion.