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In an array of one-dimensional traps, we create impurities of K atoms immersed in reservoir of Rb atoms. The impurities are first localized by an external species-selective potential and then suddenly freed: their subsequent dynamics exhibits "breathing" oscillations, due to a weaker confining potential. We find that the amplitude of these oscillations is reduced when increasing the strength of the impurity-reservoir interaction, irrespective of its sign. We interpret our data with a polaric mass shift model derived following Feynman variational approach. J. Catani et al. |
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Correlations in systems with spin degree of freedom are at the heart of fundamental phenomena, ranging from magnetism to superconductivity. The effects of correlations depend strongly on dimensionality, a striking example being one-dimensional (1D) electronic systems, extensively studied theoretically over the past fifty years. However, the experimental investigation of the role of spin multiplicity in 1D fermions — and especially for more than two spin components — is still lacking. Here we report on the realization of 1D, strongly correlated liquids of ultracold fermions interacting repulsively within SU(N) symmetry, with a tunable number N of spin components. We observe that static and dynamic properties of the system deviate from those of ideal fermions and, for N > 2, from those of a spin-1/2 Luttinger liquid. In the large-N limit, the system exhibits properties of a bosonic spinless liquid. Our results provide a testing ground for many-body theories and may lead to the observation of fundamental 1D effects. G. Pagano et al., |