화학공학소재연구정보센터
Science, Vol.355, No.6325, 620-620, 2017
QUANTUM ENTANGLEMENT Deterministic entanglement generation from driving through quantum phase transitions
Many-body entanglement is often created through the system evolution, aided by nonlinear interactions between the constituting particles. These 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 similar to 11,000 atoms by driving a rubidium-87 Bose-Einstein condensate undergoing spin mixing through two consecutive quantum phase transitions (QPTs). We directly observe number squeezing of 10.7 +/- 0.6 decibels and normalized collective spin length of 0.99 +/- 0.01. Together, these observations allow us to infer an entanglement-enhanced phase sensitivity of similar to 6 decibels beyond the standard quantum limit and an entanglement breadth of similar to 910 atoms. Our work highlights the power of generating large-scale useful entanglement by taking advantage of the different entanglement landscapes separated by QPTs.