Decoherence and pointer states in small antiferromagnets: A benchmark test

• Main Author: Hylke C. Donker, Hans De Raedt, Mikhail I. Katsnelson
• Format: Article
• Language: English
• Published: SciPost 2017-03-01
• Series: SciPost Physics
• Online Access: https://scipost.org/SciPostPhys.2.2.010

We study the decoherence process of a four spin-1/2 antiferromagnet that is coupled to an environment of spin-1/2 particles. The preferred basis of the antiferromagnet is discussed in two limiting cases and we identify two $\it{exact}$ pointer states. Decoherence near the two limits is examined whereby entropy is used to quantify the $\it{robustness}$ of states against environmental coupling. We find that close to the quantum measurement limit, the self-Hamiltonian of the system of interest can become dynamically relevant on macroscopic timescales. We illustrate this point by explicitly constructing a state that is more robust than (generic) states diagonal in the system-environment interaction Hamiltonian.