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arXiv · 2509.22182

Entanglement Hamiltonian for the massless Dirac field on a segment with an inhomogeneous background

Erik Tonni·Stefano Trezzi
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Abstract

We study the entanglement Hamiltonian of an interval for the massless Dirac field in an inhomogeneous background on a segment where the same boundary condition at both its endpoints is imposed, and in its ground state. We focus on a class of metrics that are Weyl equivalent to the flat metric through a Weyl factor that depends only on the spatial coordinate. The explicit form of the entanglement Hamiltonian is written as the sum of a local and a bilocal term. The weight function of the local term allows us to study a contour function for the entanglement entropies. For the model obtained from the continuum limit of the rainbow chain, the analytic expressions are compared with exact numerical results from the lattice, showing an excellent agreement.

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Erik Tonni, Stefano Trezzi. 2025-09-26. Entanglement Hamiltonian for the massless Dirac field on a segment with an inhomogeneous background. https://arxiv.org/abs/2509.22182

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