Capacitive Coupling of Atomic Systems to Mesoscopic Conductors

We describe a technique that enables a strong, coherent coupling between isolated neutral atoms and mesoscopic conductors. The coupling is achieved by exciting atoms trapped above the surface of a superconducting transmission line into Rydberg states with large electric dipole moments that induce voltage fluctuations in the transmission line. Using a mechanism analogous to cavity quantum electrodynamics, an atomic state can be transferred to a long-lived mode of the fluctuating voltage, atoms separated by millimeters can be entangled, or the quantum state of a solid-state device can be mapped onto atomic or photonic states.

Figure 1

Considered experimental setup (not to scale). Two atoms are located at a height $h$ above two thin normal metal disks, which are connected by a thin superconducting wire of length $L$. In the shown coplanar waveguide geometry, the wire is screened from radiative losses by a superconducting plane (lower plane). The disks and a normal metal layer (top plane) screen the wire from light used for trapping and manipulating the atoms, such that no stray light is absorbed by the superconducting wire.