Preliminary results of the trapped atom clock on a chip

We present an atomic clock based on the interrogation of magnetically trapped ⁸⁷Rb atoms. Two photons, in the microwave and radiofrequency domain excite the clock transition. At a magnetic field of 3.23 G the clock transition from |F=1, mF=-1rang to |F=2, mF=1rang is 1^st order insensitive to magnetic field variations. Long Ramsey interrogation times can thus be achieved, leading to a projected clock stability in the low 10^-13 at 1 s. We use an atom chip to cool and trap the atoms. A coplanar waveguide has been integrated to the chip to carry the Ramsey interrogation signal, making the physics package as small as (5 cm)³. We describe the experimental setup and show preliminary Ramsey fringes of line width 1.25 Hz.