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arXiv · hep-th/9508017

Momentum Scale Expansion of Sharp Cutoff Flow Equations

Tim R. Morris
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Abstract

We show how the exact renormalization group for the effective action with a sharp momentum cutoff, may be organised by expanding one-particle irreducible parts in terms of homogeneous functions of momenta of integer degree (Taylor expansions not being possible). A systematic series of approximations -- the $O(p^M)$ approximations -- result from discarding from these parts, all terms of higher than the $M^{\rm th}$ degree. These approximations preserve a field reparametrization invariance, ensuring that the field's anomalous dimension is unambiguously determined. The lowest order approximation coincides with the local potential approximation to the Wegner-Houghton equations. We discuss the practical difficulties with extending the approximation beyond $O(p^0)$.

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Tim R. Morris. 1995-09-07. Momentum Scale Expansion of Sharp Cutoff Flow Equations. https://doi.org/10.1016/0550-3213(95)00541-2

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