Quantum transfer of interacting qubits

TL;DR

This paper develops a theoretical framework for transferring the quantum state of multiple interacting qubits across a system, addressing the complexity introduced by interactions and system size, and providing explicit conditions for high-fidelity transfer.

Contribution

It introduces a general expression for the fidelity of transferring n interacting qubits using random matrix theory and quantum dynamical maps, and derives explicit conditions for high-fidelity transfer in spin chains.

Findings

Derived a formula for average and variance of transfer fidelity.

Identified conditions for high-fidelity transfer of 3 and 4 qubits.

Applied the framework to a weak-coupling spin chain model.

Abstract

The transfer of quantum information between different locations is key to many quantum information processing tasks. Whereas, the transfer of a single qubit state has been extensively investigated, the transfer of a many-body system configuration has insofar remained elusive. We address the problem of transferring the state of n interacting qubits. Both the exponentially increasing Hilbert space dimension, and the presence of interactions significantly scale-up the complexity of achieving high-fidelity transfer. By employing tools from random matrix theory and using the formalism of quantum dynamical maps, we derive a general expression for the average and the variance of the fidelity of an arbitrary quantum state transfer protocol for n interacting qubits. Finally, by adopting a weak-coupling scheme in a spin chain, we obtain the explicit conditions for high-fidelity transfer of 3 and 4 interacting qubits.