Can a periodically driven particle resist laser cooling and noise?

TL;DR

This paper investigates how a laser-cooled ion in a time-dependent anharmonic trap can maintain stable large amplitude oscillations, revealing complex nonequilibrium dynamics influenced by periodic driving and stochastic effects.

Contribution

It demonstrates the existence of stable stochastic limit cycles in a driven ion trap, showing nonequilibrium phase-space distributions with multiple peaks, a novel insight into driven microscopic systems.

Findings

Stable large amplitude trajectories persist for millions of periods.

Multiple peaks form in phase-space distribution near resonant frequencies.

Periodic drive induces nonequilibrium behavior distinct from equilibrium states.

Abstract

Studying a single atomic ion confined in a time-dependent periodic anharmonic potential, we find large amplitude trajectories stable for millions of oscillation periods in the presence of stochastic laser cooling. The competition between energy gain from the time-dependent drive and damping leads to the stabilization of such stochastic limit cycles. Instead of converging to the global minimum of the averaged potential, the steady-state phase-space distribution develops multiple peaks in the regions of phase space where the frequency of the motion is close to a multiple of the periodic drive. Such distinct nonequilibrium behaviour can be observed in realistic radio-frequency traps with laser-cooled ions, suggesting that Paul traps offer a well-controlled test-bed for studying transport and dynamics of microscopically driven systems.