Quantum State Transfer with Ising Hamiltonians

Abstract

Quantum state transfer is a fundamental requirement for scalable quantum computation, where fast, reliable communication between distant qubits is essential. In this work, we present a protocol for quantum state transfer in linear spin chains tailored to superconducting flux qubits. Starting from a perfect state transfer scheme via a Heisenberg Hamiltonian with inhomogeneous couplings [CDEL04], we adapt it to superconducting architectures by encoding the information in domain walls. The resulting Hamiltonian only contains ZZ interactions, allowing us to produce quantum transport in superconducting devices constrained to Ising-like couplings. We test the protocol for 1-, 2-, and 3- qubit states, obtaining high transfer fidelities of up to 0.99, and study the accuracy dependence on the domain wall approximation. Additionally, we analyze the protocol’s robustness to hardware errors, and determine tolerances to 7% variations in the transverse X fields, 0.9% in the coupling strengths, and up to 3MHz in local Z perturbations. Finally, we estimate the parameters required for a fluxonium qubit [MKGD09] to effectively run our algorithm, paving the way for an experimental implementation of the protocol.