English

The entropic $g$-theorem in general spacetime dimension

High Energy Physics - Theory 2023-03-29 v2

Abstract

We establish the irreversibility of renormalization group flows on a pointlike defect inserted in a dd-dimensional Lorentzian conformal field theory. We identify the impurity entropy gg with the quantum relative entropy in two equivalent ways. One involves a null deformation of the Cauchy surface, and the other is given in terms of a local quench protocol. Positivity and monotonicity of the relative entropy imply that gg decreases monotonically along renormalization group flows, and provides a clear information-theoretic meaning for this irreversibility.

Keywords

Cite

@article{arxiv.2212.10575,
  title  = {The entropic $g$-theorem in general spacetime dimension},
  author = {Horacio Casini and Ignacio Salazar Landea and Gonzalo Torroba},
  journal= {arXiv preprint arXiv:2212.10575},
  year   = {2023}
}

Comments

v2: minor corrections, matches published version. 6 pages, 2 figures

R2 v1 2026-06-28T07:45:31.229Z