Damping of local Rabi oscillations in the presence of thermal motion

Abstract

We investigate both theoretically and experimentally the effect of thermal motion of laser cooled atoms on the coherence of Rabi oscillations induced by an inhomogeneous driving field. The experimental results are in excellent agreement with the derived analytical expressions. For freely falling atoms with negligible collisions, as those used in our experiment, we find that the amplitude of the Rabi oscillations decays with time t as exp[−(t/τ ) 4 ] , where the coherence time τ drops with increasing temperature and field gradient. We discuss the consequences of these results regarding the fidelity of Rabi rotations of atomic qubits. We also show that the process is equivalent to the loss of coherence of atoms undergoing a Ramsey sequence in the presence of static magnetic field gradients -a common situation in many applications. In addition, our results are relevant for determining the resolution when utilizing atoms as field probes. Using numerical calculations, our model can be easily extended to situations in which the atoms are confined by a potential or to situations where collisions are important.

Emulation of magneto-optic Faraday effect using ultracold atoms

“…( 5), one can see that in the presence of the laser field gradient A, the Rabi oscillations are exponentially suppressed. Similar phenomena can be evidenced by experiments yet in a two-level system [33]. The atomic cloud will evolve to a steady state in which the densities saturate to…”

Production of Ultracold 87Rb133Cs in the Absolute Ground State: Complete Characterisation of the Stimulated Raman Adiabatic Passage Transfer

“…Here the dissociation and detection scheme we use means we can monitor only the total population and cannot resolve variations in the Rabi frequency across the cloud. Daniel et al . build an analytic theoretical model including the thermal motion of the sample and Rabi frequencies varying over distances smaller than the imaging resolution.…”

“…Daniel et al [39] build an analytic theoretical model including the thermal motion of the sample and Rabi frequencies varying over distances smaller than the imaging resolution. Here the dissociation and detection scheme we use means we can monitor only the total population and cannot resolve variations in the Rabi frequency across the cloud.…”

Dispersive probing of driven pseudospin dynamics in a gradient field

“…This was * nk@otago.ac.nz recently exploited to map out the microwave near field of a coplanar waveguide by means of ultracold [14] and hot [15] atomic clouds. Similarly, in the far field of a horn antenna, the effect of a spatially inhomogeneous microwave drive field has also been observed for extended atomic clouds [16]. The dynamics of the inversion w(t, ) may also acquire a position dependence through a spatial variation of the detuning .…”