Scaling atom-based quantum technologies with photonic integrated circuits

Ultracold atoms represent a highly promising platform for a variety of quantum applications, including computing, sensing and networking. However, there is limited scalability in current bulk optical implementations, and this project aims to utilise the extraordinary miniaturisation of complex quantum systems made possible with photonic integrated circuits. There is a three-pronged approach envisaged for the trapping of rubidium-87 in a Bose-Einstein condensate using a waveguide. Firstly, a grating magneto-optical trap will be prepared, using a vertically incident beam and opposing diffraction beams to cool to temperatures of ~200. Next, magnetic fields applied through external sources and nearby wires perform evaporative cooling, removing all but the coolest atoms (akin to blowing over a hot drink), and lower the atoms closer to the surface of the chip. The final stage involves using a photonic waveguide supporting blue- and red-detuned modes to the D2 transition of 87Rb. The modes' evanescent
fields above the structure respectively repel and attract the atoms, ultimately trapping them nanometres above the waveguide in a BEC. The trap may be adjusted with higher order modes, as well as standing wave potentials formed for transport. Experiments envisaged with the system include creating error correcting GKP qubit states and acceleration measurements using atom interferometry.