Deterministic entanglement generation from driving through quantum phase transitions
Abstract
Many-body entanglement is often created through system evolution, aided by non-linear interactions between the constituting particles. The very dynamics, however, can also lead to fluctuations and degradation of the entanglement if the interactions cannot be controlled. Here, we demonstrate near-deterministic generation of an entangled twin-Fock condensate of 11000 atoms by driving a 87Rb Bose-Einstein condensate undergoing spin mixing through two consecutive quantum phase transitions (QPTs). We directly observe number squeezing of 10.70.6 dB and normalized collective spin length of 0.990.01. Together, these observations allow us to infer an entanglement-enhanced phase sensitivity of 6 dB beyond the standard quantum limit and an entanglement breadth of 910 atoms. Our work highlights the power of generating large-scale useful entanglement by taking advantage of the different entanglement landscapes separated by QPTs.