Xin Lin, Barrios Maryrose, Cohen Julia T, Chapman Michael S
School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
Phys Rev Lett. 2023 Sep 29;131(13):133402. doi: 10.1103/PhysRevLett.131.133402.
We generate spin squeezed ground states in an atomic spin-1 Bose-Einstein condensate tuned near the quantum-critical point separating the different spin phases of the interacting ensemble using a novel nonadiabatic technique. In contrast to typical nonequilibrium methods for preparing atomic squeezed states by quenching through a quantum phase transition, squeezed ground states are time stationary with a constant quadrature squeezing angle. A squeezed ground state with 6-8 dB of squeezing and a constant squeezing angle is demonstrated. The long-term evolution of the squeezed ground state is measured and shows gradual decrease in the degree of squeezing over 2 s that is well modeled by a slow tuning of the Hamiltonian due to the loss of atomic density. Interestingly, modeling the gradual decrease does not require additional spin decoherence models despite a loss of 75% of the atoms.
我们使用一种新颖的非绝热技术，在靠近量子临界点调谐的原子自旋 - 1玻色 - 爱因斯坦凝聚体中产生自旋压缩基态，该量子临界点分隔了相互作用系综的不同自旋相。与通过量子相变猝灭制备原子压缩态的典型非平衡方法不同，压缩基态是时间稳定的，具有恒定的正交压缩角。展示了具有6 - 8分贝压缩和恒定压缩角的压缩基态。测量了压缩基态的长期演化，结果表明在2秒内压缩程度逐渐降低，这可以通过由于原子密度损失导致的哈密顿量缓慢调谐很好地建模。有趣的是，尽管损失了75%的原子，但对这种逐渐降低的建模并不需要额外的自旋退相干模型。
