Quantum gate in the decoherence-free subspace of trapped ion qubits

TL;DR

This paper introduces a geometric phase gate within a decoherence-free subspace of trapped ion qubits, enabling robust, scalable quantum computing with long coherence times and simplified laser requirements.

Contribution

It presents a novel geometric phase gate design in a decoherence-free subspace using trapped ions, enhancing robustness and scalability of quantum processors.

Findings

Achieved decoherence-free quantum gate operations during ion transport.

Implemented a single Raman laser field for multi-ion phase gate.

Demonstrated long coherence times in a scalable ion-trap quantum system.

Abstract

We propose a geometric phase gate in a decoherence-free subspace with trapped ions. The quantum information is encoded in the Zeeman sublevels of the ground-state and two physical qubits to make up one logical qubit with ultra long coherence time. Single- and two-qubit operations together with the transport and splitting of linear ion crystals allow for a robust and decoherence-free scalable quantum processor. For the ease of the phase gate realization we employ one Raman laser field on four ions simultaneously, i.e. no tight focus for addressing. The decoherence-free subspace is left neither during gate operations nor during the transport of quantum information.