论文标题
反馈引起的二元玻色 - 因斯坦冷凝水中的磁相
Feedback Induced Magnetic Phases in Binary Bose-Einstein Condensates
论文作者
论文摘要
与实时反馈控制的串联测量弱测量是通向工程新型非平衡量子物质的新途径。在这里，我们开发了一个理论工具箱，用于使用背面限制的弱测量结果与空间分辨的反馈结合使用，以控制多组分玻色凝结物（BEC）。单粒子电位的形式反馈可以引入有效的相互作用，这些相互作用进入随机方程式管理系统动力学。有效的相互作用是可调的，可以使其类似于feshbach的共振 - 独立于自旋和自旋依赖性 - 但没有改变原子散射参数。反馈冷却可防止由于测量反作用而导致的失控加热，我们提出了一个分析模型来解释其有效性。我们通过使用随机平均场理论来研究两个组件来展示我们的工具箱，在该理论中，反馈诱导了易于轴铁磁铁和旋转序列的paramagnet相之间的相变。我们呈现稳态相图作为固有和有效自旋依赖性相互作用强度的函数。我们的结果表明，Bose-Einstein冷凝水的闭环量子控制是冷原子系统中量子工程的强大新工具。
Weak measurement in tandem with real-time feedback control is a new route toward engineering novel non-equilibrium quantum matter. Here we develop a theoretical toolbox for quantum feedback control of multicomponent Bose-Einstein condensates (BECs) using backaction-limited weak measurements in conjunction with spatially resolved feedback. Feedback in the form of a single-particle potential can introduce effective interactions that enter into the stochastic equation governing system dynamics. The effective interactions are tunable and can be made analogous to Feshbach resonances -- spin-independent and spin-dependent -- but without changing atomic scattering parameters. Feedback cooling prevents runaway heating due to measurement backaction and we present an analytical model to explain its effectiveness. We showcase our toolbox by studying a two-component BEC using a stochastic mean-field theory, where feedback induces a phase transition between easy-axis ferromagnet and spin-disordered paramagnet phases. We present the steady-state phase diagram as a function of intrinsic and effective spin-dependent interaction strengths. Our result demonstrates that closed-loop quantum control of Bose-Einstein condensates is a powerful new tool for quantum engineering in cold-atom systems.
