An edge bit in an average symmetry protected topological mixed state (ASPT) is studied. The state is protected by one strong $Z_2$ symmetry and one weak (average) $Z_2$ symmetry. As analogous objects of pure symmetry protected topological states, the ASPT possesses edge bits. In particular, the analogous operator response, that is, symmetry fractionalization, exists. The fractionalization preserves the presence of the ASPT in the bulk and the fractionalized edge operators acting on the edge bits of the ASPT. In this work, based on the cluster model and by employing Choi map, we discuss generic features of the edge bits and numerically clarify the behavior of the edge bits and their robustness for varying decoherence and perturbative interactions. By using operator space mutual information, we track the flow of quantum correlations between the two edges. Remarkably, even in the ASPT regime, a finite portion of the initial edge-to-edge correlation survives.

Close

PrevNext

View figure in article

• Open quantum systems & decoherence
• Quantum phase transitions
• Symmetry protected topological states
• Matrix product states