Joanna Zajac (University of Manchester)
Heterogeneous quantum repeaters: III–V sources and Rb-vapor memories
Direct transmission of quantum states is limited to roughly 200 km by fibre loss and the no-cloning theorem. Quantum repeaters overcome this limit, yet existing memory-based schemes remain constrained by probabilistic photon sources. This talk presents a heterogeneous approach that pairs deterministic III–V quantum-dot sources with long-lived Rb-vapour memories, including a vapour-mediated interface between telecom O-band wavelengths and the Rb D lines. I will review the source performance and device designs developed in my laboratory, present the atomic conversion and storage scheme we use together with its modelling and initial results, and discuss current work on source–memory interfacing and on deployed fibre testing in Manchester.
Speaker bio: Joanna Zajac works on condensed-matter systems, quantum optics and quantum information, with a focus on III–V quantum dots, neutral atoms and diamond colour centres for hybrid repeaters, telecom devices and sensing. She holds an MPhys from Southampton (2008) and a PhD from Cardiff (2013) on polariton VCSELs. Postdoctoral work at Heriot-Watt addressed III–V quantum-dot single-photon sources, and at Oxford spin systems in colour centres. As a Staff Scientist at Brookhaven National Laboratory she led hybrid-repeater and telecom-device research and held a Department of Energy Early Career Award. She holds patents on photon sources and diamond devices and now leads a quantum networking and sensing group at Manchester.