标题： 通过多级振荡高效生成多体纠缠态 显示英文标题

标题： Efficient generation of many-body entangled states by multilevel oscillations

摘要： 我们通过利用多级振荡，在反铁磁自旋-1玻色-爱因斯坦凝聚体(BEC)中生成高保真度的大规模纠缠态。 将多级振荡与额外的绝热驱动相结合，我们大大缩短了必要的演化时间，并放松了对二次塞曼分裂控制精度的要求，从微高斯降至毫高斯，适用于$^{23}$Na 自旋BEC。 实现的高保真度超过$96\%$，表明两种大规模纠缠态，即多体单态和双福克态，几乎完美地生成。 即使存在原子数波动和杂散磁场，广义自旋压缩参数仍降至远低于标准量子极限的值，说明了我们的协议在真实实验条件下的鲁棒性。 生成的多体纠缠态可用于实现海森堡极限的量子精密测量，并解决量子信息科学中的非经典问题。 显示英文摘要

摘要： We generate high-fidelity massively entangled states in an antiferromagnetic spin-1 Bose-Einstein condensate (BEC) by utilizing multilevel oscillations. Combining the multilevel oscillations with additional adiabatic drives, we greatly shorten the necessary evolution time and relax the requirement on the control accuracy of quadratic Zeeman splitting, from micro-Gauss to milli-Gauss, for a $^{23}$Na spinor BEC. The achieved high fidelities over $96\%$ show that two kinds of massively entangled states, the many-body singlet state and the twin-Fock state, are almost perfectly generated. The generalized spin squeezing parameter drops to a value far below the standard quantum limit even with the presence of atom number fluctuations and stray magnetic fields, illustrating the robustness of our protocol under real experimental conditions. The generated many-body entangled states can be employed to achieve the Heisenberg-limit quantum precision measurement and to attack nonclassical problems in quantum information science.