DPhil Studentships

Demonstration of a cavity-based photonic entangler (EPSRC funded)

Entanglement, in which two quantum systems can exhibit correlations that are greater than the limit allowed by classical physics, is one of the most intriguing predictions of quantum mechanics. Entanglement between remote atoms or ions is a key resource for quantum computing, and plays a central role in the proposed NQIT Q20:20 machine.

We propose two schemes for entangling remote atoms: one probabilistic and one deterministic. In the probabilistic scheme, two distant atoms each emit a photon which are combined at the two input ports of a 50:50 beamsplitter. If the photons are detected at different output ports, then the atoms are projected into an entangled state. In place of a simple beam splitter, we also anticipate using more complex photonic networks [A. Holleczek, PRL 117, 023602 (2016)] in combination with active optical photon switching and routing. In the deterministic scheme, an atom emits a single photon which is reabsorbed by a second atom by running the emission process in reverse [J. Dilley, PRA 85, 023834 (2012)]. In doing so, the state of the first atom is entangled with that of the second. In both schemes, a high-finesse optical cavity is used to enhance the light-atom interactions.

Currently, we have two optical cavity experiments with random atom loading. The first phase of the project will be to build an optical dipole trap to permanently hold single atoms in the cavities. The feasibility of this approach has recently been demonstrated [D. Stuart, arXiv:1708.06672], and suitable fibre-tip and FIB-milled cavity mirrors are at present under development. The second phase will be to generate and quantify the entanglement between the two remote atoms using full Bell-state tomography.

Person specification

This is a highly challenging experimental project which will push the limits of laser and optical technology. It would suit a student with experience in atomic and laser physics and a keen interest in exploring quantum phenomena experimentally. EPSRC eligibility criteria apply for this project, therefore only UK students witha funding status of "Home" are eligible for the position.

To apply for this role and for further details, please follow this link: