Preliminary results of the trapped atom clock on a chip

We present an atomic clock based on the interrogation of magnetically trapped
⁸⁷
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
_F
= -1¿ to |F = 2, m
_F
= 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
^-13
at 1 s for a cloud of 10
⁵
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)
³
. We describe the experimental setup and show preliminary Ramsey fringes of line width 1.25 Hz.