arXiv subjects

Federico Capeccia

Publications and source records attributed to Federico Capeccia.

3 recordsLinked to original sources

arXiv2026

Excitability of Gaussian states with VEVs

In arXiv:2604.19861, we gave general criteria for when one zero-mean Gaussian state can be excited out of another in a (generalized) free field theory. Here we extend this analysis to the case of nonzero mean, i.e., to Gaussian states with vacuum expectation values (VEVs). We prove that excitability is possible exactly when (i) the connected two-point functions satisfy criteria like those in arXiv:2604.19861, and (ii) the difference of the VEVs is bounded relative to the two-point functions. As an application, we give an explicit computation showing that in anti-de Sitter spacetime, a VEV shift can be excited from the Klein-Gordon vacuum if and only if its boundary extrapolation can be excited from the vacuum of the dual conformal field theory.

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arXiv2026

Excitability in quantum field theory

In quantum field theory, it is not always possible to excite one state out of another using only local operators. This paper establishes abstract algebraic criteria for (local) excitability in general quantum theories, and computes these criteria explicitly for zero-mean Gaussian states in (generalized) free field theories. We find that in this context, due to the special nature of Gaussian states, one-way excitability always implies two-way excitability, and our results generalize the "quasiequivalence theorems" of Powers, Stormer, van Daele, Araki, and Yamagami. A key role in our proof is played by the information-theoretic tool of canonical purification. In appendices, we provide a pedagogical introduction to the algebraic formulation of (generalized) free field theory.

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arXiv2025

Geometric modular flows in 2d CFT and beyond

We study geometric modular flows in two-dimensional conformal field theories. We explore which states exhibit a geometric modular flow with respect to a causally complete subregion and, conversely, how to construct a state from a given geometric modular flow. Given suitable boundary conditions, we find that generic geometric modular flows in the Rindler wedge are conformally equivalent. Based on this insight, we show how conformal unitaries can be used to explicitly construct a state for each flow. We analyze these states, deriving general formulas for the energy density and entanglement entropy. We also consider geometric flows beyond the Rindler wedge setting, and in higher dimensions.

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