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## Main Question or Discussion Point

please see http://camoo.freeshell.org/dual_gauge.pdf" [Broken]

Thanks

Laura

Thanks

Laura

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- Thread starter lark
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please see http://camoo.freeshell.org/dual_gauge.pdf" [Broken]

Thanks

Laura

Thanks

Laura

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jtbell

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You can also try clicking on the sigma icon in the message-composition window, although I suspect you'll find it easier to write the code directly, because you apparently did it for that PDF file.

This will make it more convenient for readers than downloading a PDF file. Also, they can quote your equations if necessary which makes it easier to reply.

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Like so:

And so on.The following comment in a book was puzzling to me : ”Recall the Hodge dual of the Maxwell

tensor F. We could imagine a ’dual’ U(1) gauge connection that has F as its bundle curvature

rather than F.”

But [itex]F_ab[/itex] satisfies d[itex]F_ab[/itex] = 0, which means that [itex]F_ab[/itex] can be expressed as a derivative of a 1-form:

[tex]F_ab = \frac{\partial{_A}}{\partial{_b}}-\frac{\partial{A_a}}{\partial{x^b}}.[/tex]

and the vector potential [itex]A_a[/itex] gives you a gauge connection

[tex]\nabla_a= \frac{\partial}{\partial{x^a}} - ieA_a[/tex]

And so on.

So [itex]F_ab[/itex] is the

curvature of the connection,

[tex]\nabla_a \nabla{_b}-\nabla_a \nabla_b -ie =-ie \left(\frac{\partial{A_b}}{\partial{x^a}}-\frac{\partial A_b}{\partial x^b}\right)[/tex]

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I know, but I use the built-in Latex for simple things, not for long complicated posts.Hi, did you know that we have inline LaTeX capabilities here?

Laura

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Well there's the whole question anyway, parts 1 & 2. I don't know how hard pdf formatting of latex is?But

[tex]d^*F_{ab}=-\frac{*j}{\epsilon 0}[/tex]

But how can *F be a gauge curvature when d*F[itex]\neq[/itex] 0? If it were in empty

space you could come up with a 1-form [itex]Z_a[/itex] so that^{*}[itex]F_{ab}=\frac{\partial {Z_b}}{\partial{x^a}}-\frac {\partial{Z_a}}{\partial{x^b}}[/itex] , that would give

you an alternate bundle connection. Who knows what it would be a connection for!

Is the empty-space version of the Maxwell equations what you’d be using at the quantum

level? Maybe all the interactions are being described explicitly so you wouldn’t be using a

charge-current vector. What do you think?

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There's some interest in this for Yang-Mills theories and in other contexts. Anyway I think the point is that it has to be source free. Or, approximately source free (say, in some non-simply connected region). See for example the Dirac monopole.

jtbell

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Can't you simply paste the LaTeX code that you have to prepare anyway, in between the tags? Or does that not work for some reason?I use the built-in Latex for simple things, not for long complicated posts.

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Yes but the book didn't say anything about the field being source-free. Is my guess right, that in the application where the dual connection would be used, I guess on wavefunctions, that you wouldn't be including the local sources in the Maxwell equations, because you are looking at things at too small a scale to consider charge density, current etc.? He might be leaving this unsaid - but it seems like an obligatory aspect of considering the dual of the Maxwell tensor as a curvature. I spent a lot of time thinking about whether there'd be some way to get around that restriction, some other way of defining the covariant derivative that would give the dual as the curvature. But nothing really came up.There's some interest in this for Yang-Mills theories and in other contexts. Anyway I think the point is that it has to be source free. Or, approximately source free (say, in some non-simply connected region). See for example the Dirac monopole.

Laura

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