Explicit construction of the energy-momentum tensor in the large N limit

Carlo Pagani; Hidenori Sonoda

doi:10.1103/sfkr-vjkj

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arXiv · 2508.11506

Explicit construction of the energy-momentum tensor in the large N limit

Carlo Pagani·Hidenori Sonoda

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Abstract

We construct the energy-momentum tensor of the O(N) linear sigma model explicitly in the large N limit using the exact renormalization group (ERG) formalism. The energy-momentum tensor is obtained as a cutoff dependent functional of N scalar field variables. Our guiding principles behind the construction are twofold: first the energy-momentum tensor must satisfy the Ward identity for translation and rotation invariance, and second the energy-momentum tensor must satisfy a variant of the exact renormalization group equation. In the limit that the momentum cutoff goes to zero, our energy-momentum tensor gives the one-particle irreducible (1PI) effective action with the insertion of a single energy-momentum tensor operator. We verify that the energy-momentum tensor constructed satisfies the expected trace formula, and that the trace vanishes at the Wilson-Fisher critical point.

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Carlo Pagani, Hidenori Sonoda. 2025-08-15. Explicit construction of the energy-momentum tensor in the large N limit. https://doi.org/10.1103/sfkr-vjkj

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