title: Entanglement entropy of the Q≥4 quantum Potts chain.
abstract: The entanglement entropy S is an indicator of quantum correlations in the ground state of a many-body quantum system. At a second-order quantum phase-transition point in one dimension S generally has a logarithmic singularity. Here we consider quantum spin chains with a first-order quantum phase transition, the prototype being the Q-state quantum Potts chain for Q>4 and calculate S across the transition point. According to numerical, density matrix renormalization group results at the first-order quantum phase transition point S shows a jump, which is expected to vanish for Q→4^{+}. This jump is calculated in leading order as ΔS=lnQ[1-4/Q-2/(QlnQ)+O(1/Q^{2})].
authors.affiliation: Department of Physics, Kuwait University, P.O. Box 5969, Safat 13060, Kuwait.
authors.forename: Péter
authors.initials: P
authors.lastname: Lajkó
authors.affiliation: Wigner Research Centre, Institute for Solid State Physics and Optics, H-1525 Budapest, P.O. Box 49, Hungary.|Institute of Theoretical Physics, Szeged University, H-6720 Szeged, Hungary.
authors.forename: Ferenc
authors.initials: F
authors.lastname: Iglói