2019/09/20 by Louk Rademaker · 1 citation
Physics and Astronomy · Mathematics · #cond-mat.str-el #cond-mat.other #math-ph #math.MP
paper · pdf · doi:10.1103/physrevresearch.1.032018
published as Phys. Rev. Research 1, 032018 (2019) · 7 pages
arxiv created 2019/09/20 · arxiv updated 2019/11/20
We show that the exact ground state of the Lieb-Mattis Hamiltonian is an equal-weight superposition of all possible classical Néel states, and provide an exact formulation of this superposition in the z-spin basis for both S=1/2 and general S using Schwinger bosons. In general, a superposition of possible rotations on a general initial state is symmetric if and only if the initial state has a nonzero overlap with a singlet state and is otherwise made up of states that vanish due to the symmetrization. Most notably, |s, m=0 ⟩ states will vanish if symmetrized, which explains how a superposition of Néel states projects onto its singlet component.