Speaker
Description
We present the experimental characterization of coherence of light scattered from trapped ion crystals. We study the first and second order coherences and their dependence on the number of optical modes of employed detection setups. We show how the indistinguishable contributions from a large number of ions result in the measurement of photon bunching in a single-mode Hanbury-Brown and Twiss arrangement. This corresponds to a new regime of observation of the emission from an independent and well-defined number of single-photon emitters, where mutually competing requirements on a single-mode detection and on a high number of independent, i.e. mutually distant, emitters typically limit the achievable detectable photon rates and the corresponding possibility of observation of multi-photon contributions.
We analyze the possibilities of employing the observed collective coherent contribution for the maximization of collection efficiency of light scattered from linear ion crystals. Considering realistic trapping parameters in a macroscopic linear Paul trap, the trapping parameters can be optimized to maximize a signal in the axial trapping direction. We find up to two orders of magnitude increase of the detection efficiency in the limit of small numerical apertures NA$\sim~$0.1 for ion crystals containing at most 10~ions.
We present our experimental advancements in controlling the corresponding dominant experimental limitations resulting from a finite thermal motion of trapped ions. We realize the method for a robust experimental accumulation of nonclassicality of motion by deterministic incoherent modulation of thermal phonon number distribution. We demonstrate that repetitive application of the nonlinear anti-Jaynes-Cummings interaction monotonically accumulates the observable state nonclassicality and entanglement potential. The output states converge to a phonon number distribution with high overlap with a particular Fock state and visible quantum non-Gaussian aspects including corresponding negative Wigner function. We demonstrate a hierarchy of quantum non-Gaussianity criteria suitable for the atomic-mechanical systems, where mechanical heating corresponds to the typical limitation for the preservation of such sensitive properties and present its implementation on up to 10-phonon states of a trapped ion oscillator.
