Abstract:
Entanglement is an essential resource for quantum technologies such as quantum metrology with atomic clocks and interferometers. At the same time, it is a fundamental concept of quantum physics that still presents conceptual challenges, in particular when applied to many-body systems of indistinguishable particles. For example, spin-squeezed and other non-classical states of atomic ensembles were used to enhance measurement precision in quantum metrology, but the notion of entanglement in these systems was debated because the correlations between the indistinguishable atoms were witnessed by collective measurements only.
In this work we experimentally prepare two-component Rubidium-87 BECs, consisting of a few hundred atoms, on an atom-chip. Using state-selective potentials to tune the collisional interactions (one-axis twisting dynamics), we prepare many-particle non-classical states. After a time-of-flight expansion, high-resolution images allows us to access sub-regions of the atomic density distribution of various shapes and measure the spin correlations between them. We observe that bi-partitions violate a separability criterion, showing the presence of entanglement between different spatial regions of our many-body system. In some of such partitions, entanglement is strong enough for Einstein-Podolsky-Rosen steering: measurement outcomes for non-commuting observables in one spatial region can be predicted based on a corresponding measurement in the other region with an inferred uncertainty product below the Heisenberg relation.
Biography:
Matteo Fadel received his master in Physics from ETH Zurich and he completed his PhD in the group of Philipp Treutlein at the University of Basel. His doctoral studies focused on exploring multipartite nonclassical correlations (entanglement, Einstein-Podolsky-Rosen steering and Bell correlations) both theoretically and experimentally in spin-squeezed Bose-Einstein condensates.
Seminar by the NYU-ECNU Institute of Physics at NYU Shanghai