Thermal entanglement and lower bound of the geometric discord for a two-qutrit system with linear coupling and nonuniform external magnetic field

摘要

The effects of temperature and linear coupling constant on the lower bound of the geometric discord and negativity of a qutrit-qutrit system in Heisenberg model with (and without) parallel and antiparallel external magnetic fields have been investigated. We show that the lower bound of the geometric discord and negativity are about zero for negative linear coupling constant in parallel magnetic fields, while they are nonzero in the finite antiparallel magnetic fields. For negative linear coupling constant, as temperature increases, bothmeasures become zero faster than in the case of positive linear coupling constant in antiparallel magnetic fields.