Rényi entropy and negativity for massless Dirac fermions at conformal interfaces and junctions

Abstract

We investigate the ground state of a (1+1)-dimensional conformal field theory built with $M$ species of massless free Dirac fermions coupled at one boundary point via a conformal junction/interface. Each CFT represents a wire of finite length $L$. We develop a systematic strategy to compute the Rényi entropies for a generic bipartition between the wires and the entanglement negativity between two non-complementary sets of wires. Both these entanglement measures turn out to grow logarithmically with $L$ with an exactly calculated universal prefactor depending on the details of the junction and of the bipartition. These analytic predictions are tested numerically for junctions of free Fermi gases, finding perfect agreement.

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Cited by in corpus (5)

• Domain wall melting across a defect
• Entanglement and negativity Hamiltonians for the massless Dirac field on the half line
• Entanglement evolution after a global quench across a conformal defect
• Entanglement Negativity and Defect Extremal Surface
• Entanglement entropies of an interval in the free Schrödinger field theory on the half line