****TECHNICAL ABSTRACT**** This project seeks to study cavity quantum electrodynamics, many-body dynamics, and eventually quantum information, using electrons floating above superfluid helium. Electrons on helium form a unique two-dimensional electron gas levitated by zero-point motion above the superfluid surface. It is exceptionally clean, having the highest known mobility, and is predicted to have long spin coherence, but while it has been studied for many years, little is known about the properties of individual electrons. This project will use superconducting transmission line cavities coherently coupled to first ensembles, and eventually individual trapped electrons. Calculations predict that both the charge and spin dynamics of single electrons on helium possess long coherence times, but these will be the first experimental measurements. These experiments are only possible now because of recent advances in superconducting circuit technology. This project will support the education of a PhD student in these advanced technologies, which has historically shown itself to be excellent training for many scientific careers from academia to our most advanced technology industries. This research combining multiple quantum coherent systems is expected to be of broad interest to the scientific community, and serve as a template for efforts in other fields.
When electrons are sprayed onto the surface of an insulating liquid, they stick to the surface. Amazingly, at low temperatures, just a few degrees above absolute zero, they begin to levitate a few nanometers above the surface due to quantum mechanical effects. When working with atoms or particles, most of the technical challenge is in trapping them in vacuum, but in this special system, the electrons naturally float, like microscopic buoys on the ocean. Because they are levitated, they have pristine properties, but like buoys, they also have complex interactions with waves in the fluid below. This project will pursue experiments to isolate single electrons floating on helium, and probe their complex interactions with light, superfluid waves, and each other. This will be accomplished by employing the most advanced tools of experimental science: nanofabrication, ultra-low temperature physics, and quantum computing electronic devices. This project will support the education of a PhD student in these advanced technologies, which has historically shown itself to be excellent training for many scientific careers from academia to our most advanced technology industries. These studies will advance our understanding of this fascinating system and eventually could lead to quantum computers in which bits are stored by individual electrons, using little power and exponentially speeding important classes of computations.
