Additivity of disjoint interval entanglement in quasiparticle excited states (opens in new tab)

We investigate mixed-state entanglement measures, namely reflected entropy, mutual information and logarithmic negativity, for two disjoint intervals in one-dimensional systems excited by a finite number of quasiparticles. While whole system is in a pure state, the two disjoint intervals are in a generically mixed state. To address the problem that natural subsystem bases are generically non-orthonormal in such excited states, we use a general and efficient algorithm that computes these measu...