Frequency measurements of cold-atom clocks

Kurt Gibble

We theoretically analyze frequency shifts of cold-atom clocks due to background gas collisions. Because nearly all collisions with room-temperature background gases that transfer momentum eject cold atoms from a clock, the frequency shifts for cold atoms are significantly different than those of room-temperature clocks. From general arguments, measurements of the loss of Ramsey fringe amplitude can usefully bound this source of systematic error.

Chad Fertig, Ronald Legere, J.Irfon Rees +3 more

Luc Archambault, Bruno Pelle, L. Lorini +3 more

Wei Ren, Yuan-Ci Gao, Tang Li +2 more

The performance of space cold atom clocks (SCACs) should be improved thanks to the microgravity environment in space. The microwave interrogation cavity is a key element in a SCAC. In this paper, we develop a microwave interrogation cavity especially for the rubidium SCAC. The interrogation cavity has two microwave interaction zones with a single feed-in source, which is located at the center of the cavity for symmetric coupling excitation and to ensure that the two interaction zones are in phase. The interrogation cavity has a measured resonance frequency of 6.835056471 GHz with a loaded quality factor of nearly 4200, which shows good agreement with simulation results. We measure the Rabi frequency of the clock transition of the rubidium atom in each microwave interaction zone, and subsequently demonstrate that the distributions of the magnetic field in the two interaction zones are the same and meet all requirements of the rubidium SCAC.

S. Trémine, François-Xavier Esnault, Stéphane Guérandel +3 more

HORACE is a compact cold Cs atom clock where laser cooling, microwave interrogation and clock signal detection are all performed inside a spherical microwave cavity. We present the signals observed on the new clock prototype. The frequency stability is estimated from clock signal measurements.

Steven Peil, J. L. Hanssen, Thomas B. Swanson +2 more