The interplay between ultracold atoms, semiconductor surfaces and quantum electronic systems

Mark Fromhold, U of Nottingham

This talk will explore how room-temperature semiconductor surfaces can manipulate atoms cooled to nK temperatures and, conversely, be probed by the atoms themselves.

Quantum-mechanical reflection can shield the ultracold atoms from the disruptive influence of a nearby room-temperature surface. By considering experiments performed at MIT [1], it will be shown that inter-atomic interactions and the aspect ratio of the condensate both strongly affect the reflection process [2].

Next, the interaction between atomic condensates and surfaces that are patterned on the nanometre and micrometre scales will be considered. Strong focusing of the condensate by a transmission zone plate suggests a route towards re-writable matter-wave lithography of quantum electronic devices [2].

Finally, I will present calculations, which predict that current through a two-dimensional electron gas (2DEG) can trap ultracold atoms < 1 micron away with orders of magnitude less spatial noise than a more usual metal trapping wire [3]. This may enable the creation of hybrid systems, which integrate ultracold atoms with quantum electronic devices to give high sensitivity and control: for example, activating a single quantised conductance channel in the 2DEG can split a Bose-Einstein condensate (BEC) for atom interferometry. In turn, the BEC itself offers structural and functional imaging of quantum devices and transport.