Global Doctoral Scholarship – St Andrews and Bonn – Physics

Ultracold atoms provide an excellent platform to understand many-body quantum systems. This has allowed the study of many material properties, such as transitions between conducting and insulating states, magnetic order, and transport. In particular it has not been possible to model how electrons in a solid interact with phonons. Several groups have developed experiments with cold atoms (both bosons and fermions) in cavities. Our experimental collaborator Prof. Lev is unique in using cavities which support many nearly degenerate modes of light. This crucially yields controllable-range atomic interaction, necessary to realistically model phonons. Experiments with fermionic atoms in such cavities are now being built.

This project will identify ways to stimulate superconductivity using fermionic atoms in multimode cavities. To realise superconductivity, we must use the cavity to engineer density-density interactions between atoms. This contrasts with most existing work, where interactions occur between atomic density waves, due to recoil from scattering photons. Preliminary work indicates that by trapping the atoms in a two dimensional later, recoil can be suppressed, producing a direct density-density interaction, as recently used to realise density-density interactions in a one-dimensional chain.

After demonstrating the possibility of superconducting pairing, we will build on recent work, to explore heating and cooling rates induced by the cavity. Understanding such heating is key to identifying how experiments must be defined: if heating rates are too high, it will be necessary to consider experiments that measure transient signals. This question requires new theoretical approaches, since exact simulation of the experiments is not practical. We will compare cumulant-based and adiabatic elimination approaches developed by our groups.

“Applications will be considered until the position is filled”