Cold Atoms as an Optical Quantum Memory

An optical quantum memory, a device which can store and retrieve an arbitrary quantum state at the single photon level, has been identified as a significant cornerstone of photonic quantum technologies. The development of such a memory would allow the creation and development of a large number of quantum technologies. These would range from the ability to synchronise processing steps in an optical quantum computer, to the construction of a quantum repeater which would allow faithful transmission of quantum states over arbitrarily long distances - allowing the creation of a quantum internet.

This project will work on developing optical quantum memories where the input quantum state (e.g. a single photon) is stored as an excitation within an atomic ensemble. To perform storage, we mediate the absorption of the quantum state by simultaneously addressing the ensemble with an additional (control) laser pulse. To retrieve our quantum state from the atoms, the control field is reapplied at a later time, recreating the input photon on demand. By manipulating the amplitude and phase of the control field relative to the signal, we are able to optimise the atomic interaction leading to longer storage lifetimes and higher storage efficiencies.

This research spans quantum optics, atomic physics and quantum technologies with the aim to build a high efficiency cold atom quantum memory system. Cold Atom systems are some of the most promising mediums in which to store quantum states, with the reduced motion of the atoms offering the potential for long storage times. There is substantial effort, both academic and commercial to simplify and miniaturise cold atom sources for quantum technology. This project will build on world class developments in this area and optimise developing all aspects of a cold atom quantum memory,

This project would suit an experimental student with a strong background in Physics or Engineering and an interest in quantum technologies.