Entanglement entropy and spin-chain generalizations of conserved-momentum local quenches

Derive the entanglement entropy for the generalized local-quench protocol with distinct chiral and anti-chiral regulators, and generalize this conserved-momentum local-quench construction to spin chains.

Background

The paper introduces a generalized local-quench protocol in two-dimensional conformal field theory by replacing the standard uniformizing maps with separate left- and right-moving maps characterized by regulators ε₋ and ε₊. These parameters encode distinct chiral excitations and, in the holographic description, conserved momentum carried by an infalling particle.

The authors provide stress-tensor expectation values and uniformizing maps for this generalized setup, including versions at zero temperature, finite temperature, and finite spatial size. However, they do not derive the entanglement entropy for the protocol or investigate how the construction extends beyond conformal field theory to spin-chain systems; these tasks are explicitly deferred to future work.

References

Nevertheless, we leave interesting follow-ups, such as the derivation of entanglement entropy or generalization of this setting into spin-chains, to the upcoming works.

— Holographic Local Operator Quenches with Conserved Momentum and Spin  (2608.19305 - Caputa et al., 19 Aug 2026) in Section 6, subsection “Local quenches with conserved momentum”