A tomography of many-body quantum states of indistinguishable particles is generally performed by global couplings between the involved states and a subsequent counting of the occupation numbers. While precise couplings belong to the standard toolbox, an accurate number counting presents a considerable challenge for both photonic and atomic quantum states. Here we present an application of a number-resolving atom counting for the state reconstruction of an atomic coherent spin state. We generate a coherent spin state by driving a Rabi coupling between the two hyperfine clock states of an ultracold rubidium ensemble. The result is analyzed by a number-resolving fluorescence detection setup. We characterize the fidelity of our detector and show that a negative-valued Wigner function is associated with it. The results offer an exciting perspective for the high-fidelity tomography of entangled states and can be applied for the future demonstration of Heisenberg-limited atom interferometry.
|Presenter name||Mareike Hetzel|
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