Preliminary results of the trapped atom clock on a chip

International audienceWe present an atomic clock based on the interrogation of magnetically trapped <sup>87</sup>Rb 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, m<sub>F</sub> = -1¿ to |F = 2, m<sub>F</sub> = 1¿ is 1st-order insensitive to magnetic field variations. Ramsey interrogation times longer than 2 s can be achieved, leading to a projected clock stability in the low 10<sup>-13</sup> at 1 s for a cloud of 10<sup>5</sup> atoms. We use an atom chip to cool and trap the atoms. A coplanar waveguide is integrated to the chip to carry the Ramsey interrogation signal, making the physics package as small as (5 cm)<sup>3</sup>. We describe the experimental setup and show preliminary Ramsey fringes of line width 1.25 Hz