Quantum steering in magnetic Heisenberg models at finite temperature

Mathematics and Physics Department, North China Electric Power University - Beijing, 102206, China

^(a) slchern@ncepu.edu.cn
^(b) yqzhang@ncepu.edu.cn

Received: 26 October 2017
Accepted: 7 February 2018

Abstract

We investigate the behavior of quantum steering for a pair of quantum qubits described by the Heisenberg model with external magnetic field and in equilibrium with a reservoir at temperature T. Generally, the steerable weight, which is used to identify the steerability, is suppressed by thermal fluctuations. When the magnetic field is vanishing, the steerable weight behaves like the quantum entanglement. When the magnetic field is not zero, the steerable weight is dramatically different from the other quantities used to identify the quantum correlations between the two spins, i.e., the concurrence, quantum discord and coherence. In the strong magnetic field limit, all of the other quantities we studied are vanishing for the Ising model, while steerable weight tends to one. This demonstrates that the strong transverse magnetic field is helpful to preserve the quantum steerability of the Ising model.