Interfacing Ultracold Polar Molecules with Rydberg atoms: A Hybrid Platform for Quantum Science

The predictions of quantum mechanics, the theory that governs all matter at a microscopic level, are often fascinating and sometimes mystifying. At the heart of this theory are two fundamental concepts. The first, wave-particle duality, implies that particles, such as electrons in an atom, can behave like waves and that light waves can behave like particles. The second, entanglement, is the concept that once two (or more) particles have interacted, they cannot be treated as independent entities no matter how far apart they are. These inherently quantum properties can lead to phenomena that defy our classical intuition. Superconductivity, the flow of charge through a material without resistance, is an excellent example.

Currently, there is world-wide interest in harnessing the unique properties of quantum mechanics to develop a new-wave of technological devices that have the potential to surpass even the best classical counterparts, just as a superconductor outperforms copper. We can expect such quantum technologies to deliver more powerful methods of computation, completely secure communication, enhanced metrology and sensors with unparalleled sensitivity. Many different physical platforms are being developed for quantum technologies, including trapped ions, ultracold atoms, superconducting devices and photons. Each platform has its own strengths and weaknesses, with no single system providing the ideal architecture. A solution to this problem is to construct a hybrid platform combining two (or more) unique quantum systems in such a way as to profit from their individual advantages whilst simultaneously mitigating their disadvantages.

In this context, we propose to combine ultracold polar molecules and highly-excited Rydberg atoms in a flexible platform using optical tweezer arrays. This innovative approach aims to leverage the richness associated with the long-lived rotational states of molecules by interfacing them with strongly interacting Rydberg atoms to realise a hybrid quantum system ideally suited to investigate problems in quantum science and technology. Our platform promises new capabilities and a wealth of future research directions including (a) The non-destructive detection and readout of the internal rotational state of a polar molecule for applications in quantum simulation. (b) The creation of a new class of ultracold molecules, Giant Polyatomic Rydberg Molecules, providing a testbed for studying fundamental electron molecule scattering in the quantum regime. (c) The implementation of fast molecule-molecule quantum gates mediated by a Rydberg atom for applications in quantum information processing. (d) The realisation of effective spin-spin interactions between molecules in an optical lattice mediated by Rydberg atoms for studies of quantum magnetism.

Our vision is underpinned by the existence of strong long-range charge-dipole interactions between a diatomic polar molecule and a Rydberg atom. The goal of this two-year research project is to measure and learn to control these interactions using single atoms and molecules confined in tightly confining optical traps, known as optical tweezers. This will provide a springboard to the longer-term objectives of our research vision.