Entanglement of magnon excitations in spin chains

Abstract

We calculate exactly the entanglement content of magnon excited states in the integrable spin-1/2 XXX and XXZ chains in the scaling limit. In particular, we show that as far as the number of excited magnons with respect to the size of the system is small one can decompose the entanglement content, in the scaling limit, to the sum of the entanglement of particular excited states of free fermionic or bosonic theories. In addition we conjecture that the entanglement content of the generic translational invariant free fermionic and bosonic Hamiltonians can be also classified, in the scaling limit, with respect to the entanglement content of the fermionic and bosonic chains with the number operator as the Hamiltonian in certain circumstances. Our results effectively classify the entanglement content of wide range of integrable spin chains in the scaling limit.

Lax operator and superspin chains from 4D CS gauge theory

“…These super magnons are generalisations of the standard sl (m) magnons which are quasi-particles of the integrable quantum spin chains given by excitation modes of the ground state |Ω Λ labeled by a highest weight vector Λ of the symmetry group. For the SU (2) spin, the magnons are quantised spin waves that was extensively studied in physical literature with regards to the magnetic properties of materials and the entanglement [37]- [40]. In particular, the superspin chain models that we are interested in here are of particular utility due to the special structure of super algebras and the rich structure they hold.…”

Generalized entanglement entropies in two-dimensional conformal field theory

“…The simplest class of excited states in a CFT are those generated by the action of a primary field Υ. The von Neumann and Rényi entropies in excited states of CFT have then been the subject of intensive investigations [13][14][15][16][17][18][19][20][21][22][23][24][25][26].…”