Spatially Resolved Detection of a Spin-Entanglement Wave in a Bose-Hubbard Chain

Understand

Entanglement is an essential property of quantum many-body systems.

• However, its local detection is challenging and was so far limited to spin degrees of freedom in ion chains.
• Here we measure entanglement between the spins of atoms located on two lattice sites in a one-dimensional Bose-Hubbard chain which features both local spin- and particle-number fluctuations.
• Starting with an initially localized spin impurity, we observe an outwards propagating entanglement wave and show quantitatively how entanglement in the spin sector rapidly decreases with increasing particle-number fluctuations in the chain.