Higginbottom, DanielGeng, JiaoCampbell, GeoffHosseini, MahdiCao, M TSparkes, BenjaminBernu, JulienRobins, NicholasLam, Ping KoyBuchler, Benjamin2018-11-292018-11-291094-4087http://hdl.handle.net/1885/152919We introduce a scheme for the parallel storage of frequency separated signals in an optical memory and demonstrate that this dual-rail storage is a suitable memory for high fidelity frequency qubits. The two signals are stored simultaneously in the Zeeman-split Raman absorption lines of a cold atom ensemble using gradient echo memory techniques. Analysis of the split-Zeeman storage shows that the memory can be configured to preserve the relative amplitude and phase of the frequency separated signals. In an experimental demonstration dual-frequency pulses are recalled with 35% efficiency, 82% interference fringe visibility, and 6° phase stability. The fidelity of the frequency-qubit memory is limited by frequency-dependent polarisation rotation and ambient magnetic field fluctuations, our analysis describes how these can be addressed in an alternative configuration.application/pdfDespite being sent instructions on how to reduce a file to fit Aries, nothing worked, so I have split it into two scanned docs and uploaded that way.Aries is telling me the document I tried to upload exceed's size limits. I have therefore emailed it to Publications to upload for me.201510.1364/OE.23.0249372018-11-29