Cavity-QED with multi-species ion crystals

The aim of the proposed PhD project is to investigate the use of two-species ion crystals in the cavity-based implementation of the photonic link between quantum processors. In the first part of the project, strontium ions will be employed as a refrigerant to enable the continuous, high-rate generation of entanglement between a co-trapped calcium ion and cavity photons. Removing the need for laser cooling of the calcium ion will increase the entanglement rate without compromising the fidelity. The second stage of the project will then include quantum state transfer between the two species consecutive to the generation of ion-photon entanglement. Here the focus will be on the transfer of the ion-photon entangled state from the calcium ion, initially used to generate the entanglement via a cavity-assisted transition, to the co-trapped strontium ion.
To this end, an existing ion-cavity system will be extended to operate with both ion species and the QCS Hub-funded laser systems for strontium and calcium ions will be used.
The project will be pursued in collaboration with the group of David Lucas at Oxford, which has experience in working with two-species ion crystals. The PhD student will spend some time at Oxford to learn from David's team and transfer some of the know-how to Sussex.
1. How the project would contribute to the Hubs' goals:
The project will contribute to achieving Deliverable 1.9. As identified in the first phase of the Quantum Technology Hub Programme, ion-cavity systems are essential to achieve a fully scalable quantum computer and this PhD project will help to deliver such a scalable technology and demonstrate its functionality. Extending this to a two-ion species operation is a significant step towards a practical implementation of an ion-based quantum computer.
2. How the studentship would fit in with any planned QCS staffing on the project:
The student will be supervised by Prof Keller and will work with Dr Graham Stutter (QCS Hub funded postdoc) and existing senior PhD students.
3. How the project would fit in with the wider QCS programme - would there be opportunities for students to work in collaboration with other groups and partner institutions:
While the main work is based in Sussex, during the initial phase of the project frequent discussions with the ion-trapping group at Oxford are expected to take advantage of their expertise in working with two-species ion crystals. To make full use of this, the student will spend time in the group at Oxford to learn how to work with two-species ion crystals.
4. What facilities / apparatus would be available for the student to use in the project, what training would be provided and by whom:
Facilities: The Sussex group provides a fully functioning ion trap system with all lasers that are required for the two-species experiment.
Training: The student will join the Sussex Doctoral School, which provides training in general research skills, transferable skills and commercialisation training (through the Sussex Innovation Centre). In addition, the student will receive training in QIP and QT through our taught modules and QT hub activities. The main training will be through their laboratory work where the student will receive training in ion trap technology, laser control of trapped ions, electronics, optics and vacuum technology. Prof Keller and his research team will deliver this training.
5. How you will ensure there is a diverse pool of applicants for the studentship:
A gender-balanced panel will conduct the PhD student recruitment and the advertisement will be checked for gender bias. All staff is required to be trained in recruitment, and equality and diversity. In particular, training in unconscious bias is required for all staff on recruitment in interview panels. In general, the Sussex School for Mathematical and Physical sciences is committed to promote diversity and equality at every step in the recruitment process