A Gaudin-like determinant for overlaps of Néel and XXZ Bethe states

Abstract

We derive a determinant expression for overlaps of Bethe states of the XXZ\nspin chain with the N{\\'e}el state, the ground state of the system in the\nantiferromagnetic Ising limit. Our formula, of determinant form, is valid for\ngeneric system size. Interestingly, it is remarkably similar to the well-known\nGaudin formula for the norm of Bethe states, and to another recently-derived\noverlap formula appearing in the Lieb-Liniger model.\n