Quantum entanglement entropy and classical mutual information in long-range harmonic oscillators

Understand

We study different aspects of quantum von Neumann and R\'enyi entanglement entropy of one dimensional long-range harmonic oscillators that can be described by well-defined non-local field theories.

• We show that the entanglement entropy of one interval with respect to the rest changes logarithmically with the number of oscillators inside the subsystem.
• This is true also in the presence of different boundary conditions.
• We show that the coefficients of the logarithms coming from different boundary conditions can be reduced to just two different universal coefficients.