Lamb Dicke regime

In ion trapping and atomic physics experiments, the Lamb Dicke regime (or Lamb Dicke limit) is a quantum regime within an atom-light field system in which the spatial extent of the atom's wavefunction is much smaller than the wavelength of the addressing light field. In this regime, the coupling between an ion or atom's internal qubit states and its motional states is sufficiently small so that transitions that change the motional quantum number by more than one are strongly suppressed.

This condition is quantitively expressed by the inequality

${\displaystyle \eta ^{2}(2n+1)\ll 1,}$

where ${\displaystyle \eta }$ is the Lamb–Dicke parameter and ${\displaystyle n}$ is the motional quantum number of the ion or atom's harmonic oscillator state.