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Entanglement Verification Enabling New Technologies

Final Report Summary - EVENT (Entanglement Verification Enabling New Technologies)

Quantum technology promises the next revolution in information processing and communication. It is a widely held theory, that entanglement, a truly quantum phenomenon lies at the heart of these future technologies. eVent – Entanglement Verification Enabling New Technologies, attempted to solve one major challenge on the route to this transformative technology: entanglement verification.

Entanglement is a counter-intuitive properties of quantum systems, and verifying it in a loop-hole free one has opened the door to many exciting new technologies, i.e device-independent cryptographic security. However, to date, many of these powerful ideas are yet to be implemented experimentally. The challenge has been the production and verification of the building block of these protocols, the entangled resources state.

Photonics, that is, physics using light, has been at the forefront of the quantum revolution since the early 1900s. It has been because it is easy-to-use, requires no complicated cryogenics, and works robustly at room temperature. We aimed to continue this tradition in eVent, building the entangled resource out of entangled particles of light.

To date, these entangled states have struggled to increase in number. This is because photonics faces a great challenge, the complexity and waiting time of current experiments increases exponentially with photon number. This has limited the state-of-the-art experiments to 4 entangled pairs, while demonstrator protocols require many more resources states. eVent aimed to solve this challenge using a robust, room-temperature, entangled state factory build from broadband quantum memories.

Throughout eVent, the research fellow (RF) has facilitated knowledge transfer and has main considerable scientific progress under the leadership of the scientist in charge, Prof. Ian Walmsley (SIC), within the larger Ultrafast Quantum Optics Group (UFQO) at the University of Oxford. Within the UFGO the RF has led the memories subgroup, a team of 10 currently, which works alongside the photonics subgroup, led by Dr. Steve Kolthammer, a team of 15 currently.

The RF has been involved in activities from, leading and developing experimental efforts in the laboratory, formulating broader research directions, data analysis, scientific and public dissemination of both our results, and popular science topics. The RF has co-supervised graduate students, alongside the SIC.

As mentioned in the first periodic report, the first milestone of the project encounted a major problem. This problem was anticipated, and planned for in the risk mitigation (pg. 23) of the proposal. However, the solution was more nuisance than first anticipated and caused a significant delay to the main work program, however, in solving this problem, new research direction emerged. These new work directions, while distinct, follow a similar path as those listed in Annex 1.

While leading the memory sub-team in the UFQO group, the RF has published 10 papers in international physics journals. 2 of these were in collaboration with Australian research groups, 1 with close collaboration with Bristol University UK, and the other 5 where direct outcomes of the work proposed in this proposal. Of these 7 papers, the RF was first author on a published in the prestigious Physical Review Letters. Furthermore, the RF also published a last-author paper following this. These two papers demonstrate the RFs ability to lead, both at the experimental level, and his transition to leading at a planning, development level.

eVent consists of two aims: one, knowledge transfer and scientific discovery. The knowledge transfer, was divided into three parts. The first, bringing entanglement to Oxford, was completed and resulted in a BBC Documentary being filmed in Oxford and two papers being published on the topic whilst at Oxford. The second, Contribute to the collected expertise at Oxford, was completed as the RF published one first author paper on light-matter storage, and one last author paper on the same topic, as well as other papers during his stay. The last objective, unite disparate knowledge from Australia to Europe, has been completed by first strengthening Oxford Australia relations by attracting three postdocs from Australia/New Zealand to Oxford during his stay. Furthermore, visits to Australia to disseminating work, and finally by a planned student exchange program with Griffith University, Brisbane, Australia, demonstrate the RF success in this objective.

Therefore it is clear that the RF completed, and went beyond the initial outline for knowledge of transfer.

Moving now to scientific progress, the RF has taken a slightly different path than that proposed in the initial program. This is because it was discovered after the RF arrived at UFQO that there was a prohibitive noise in the Raman memory that stalled progress. There was a risk mitigation strategy in place in the initial report, and this strategy was than adopted.

Milestone one is yet to be completed, this is due to a significant delay. This was outlined in the first periodic report. Because the other milestones run on directly from M1, they too have not been completed. Nevertheless, significant scientific progress and discover has taken place by the RF at UFOG during his MC fellowship.

In closing, while the initial milestones of the proposal were not completed because of an extensive study into cavity enhanced quantum memories, the RF believes that the research output and potential impact of cavity-enhanced quantum memories has made eVent a success. Even though the initial work plan had to be adjusted because M1 proved to be much harder than first anticipated. Nevertheless, the 8 published papers (with two more under review) demonstrate that the scientific output of eVent will have long lasting impact. This combined with the 600 000 people who watched the BBC documentary the RF produced, simple demonstrate the success and lasting impact of this project.