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Low curvature effective action in string theory

  1. Aug 26, 2014 #1
    String effective action:
    [tex]
    S=-\frac{1}{2\lambda_{\text{s}}^{d-1}}\int d^{d+1}x\sqrt{|g|}e^{-\phi}\left[R+(\nabla\phi)^2+2\lambda_{\text{s}}^{d-1}V(\phi)-\frac{1}{12}H^2\right]+S_m
    [/tex]
    where
    [tex]
    H^2=H_{\mu\nu\alpha}H^{\mu\nu\alpha}\\
    H_{\mu\nu\alpha}=\partial_\mu B_{\nu\alpha}+\partial_\nu B_{\alpha\mu}+\partial_{\alpha} H_{\mu\nu}
    [/tex]
    and [itex]B_{\mu\nu}[/itex], [itex]\phi[/itex] and [itex]R[/itex] are antisymmetric tensor, dilaton, Ricci scalar on target space respectively.

    Effective action can be derived by expanding the [itex]\sigma[/itex]-model action in powers of [itex]R[/itex].
    But where do the matter sector [itex]S_m[/itex] and ambiguity of dilation potential [itex]V(\phi)[/itex] come from?
    If this action can be derived by this way, I'm afraid the effective action is determined uniquely and new matter fields don't appear.
     
  2. jcsd
  3. Sep 1, 2014 #2
    I'm sorry you are not finding help at the moment. Is there any additional information you can share with us?
     
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