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TT: Fachverband Tiefe Temperaturen

TT 93: Quantum Coherence and Quantum Information Systems (joint session TT/MA)

TT 93.7: Vortrag

Donnerstag, 15. März 2018, 16:45–17:00, H 2053

Quantum spin systems at the edge of a quantum memory — •Yevheniia Cheipesh, Lorenzo Cevolani, and Stefan Kehrein — University of Göttingen

We consider the Kitaev Toric Code with open boundary conditions. This system has a highly degenerate ground state that lives on the boundary and can be described as a one dimensional system. The ground state is derived explicitly and its dimension scales exponentially with the size of the system. Based on this, the entanglement properties of the model are studied for two types of bipartition: the first, where the subsystem A is completely contained in B; and the second, where the boundary of the system is shared between A and B. In the former case the entanglement entropy is the same as for periodic boundary conditions, which means that the bulk is completely decoupled from the boundary on distances larger than the correlation length. In the latter, deviations from the torus configuration appear due to the edge states, and lead to the increase of the entropy. We also derive the dispersion relation of the boundary theory under the perturbation with an external magnetic field along the x-direction.