Far-from-equilibrium noise heating and laser cooling dynamics in radio-frequency Paul traps
A Maitra, Dietrich Leibfried, D. Ullmo, H. Landa
We study the stochastic dynamics of a particle subject to a periodically driven potential. For atomic ions trapped in radio-frequency Paul traps, noise heating and laser cooling typically act slowly in comparison with the timescale of the unperturbed motion. These stochastic processes can be accounted for in terms of a probability distribution defined over the action variables, that would otherwise be conserved within the regular regions of the Hamiltonian phase-space. We present a semiclassical theory of low saturation laser cooling applicable from the limit of low amplitude motion to large amplitude motion, accounting fully for the time- dependence of the trap. We employ our approach to a detailed study of the stochastic dynamics of an ion in the different regimes of motion within an anharmonic radio-frequency Paul trap, drawing general conclusions regarding the nonequilibrium dynamics of trapped ions. We predict a regime of anharmonic motion with laser cooling becoming diffusive (i.e. it is equally likely to cool the ion as it is to heat it), and also turning into an effective heating. Such a mechanism implies that a high-energy ion would be easily lost from the trap despite being laser cooled, however we find it can be counteracted using a large laser detuning. More generally, the presented theory applies to a broad range of periodically driven systems and out-of-equilibrium stochastic dynamics.
, Leibfried, D.
, Ullmo, D.
and Landa, H.
Far-from-equilibrium noise heating and laser cooling dynamics in radio-frequency Paul traps, Physical Review A, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=926969
(Accessed November 30, 2023)