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arXiv · 1602.00299

Protected ground states in short chains of coupled spins in circuit quantum electrodynamics

Adam Callison·Eytan Grosfeld·Eran Ginossar
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Abstract

The two degenerate ground states of the anisotropic Heisenberg (XY) spin model of a chain of qubits (pseudo-spins) can encode quantum information, but their degree of protection against local perturbations is known to be only partial. We examine the properties of the system in the presence of non-local spin-spin interactions, possibly emerging from the quantum electrodynamics of the device. We find a phase distinct from the XY phase admitting two ground states which are highly protected against all local field perturbations, persisting across a range of parameters. In the context of the XY chain we discuss how the coupling between two ground states can be used to observe signatures of topological edge states in a small controlled chain of superconducting transmon qubits.

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Adam Callison, Eytan Grosfeld, Eran Ginossar. 2016-01-31. Protected ground states in short chains of coupled spins in circuit quantum electrodynamics. https://doi.org/10.1103/physrevb.96.085121

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