论文标题
Harper-Hofstadter模型中的连贯性和变形
Coherence and decoherence in the Harper-Hofstadter model
论文作者
论文摘要
我们使用原子Bose-Einstein冷凝物在高度细长的管几何形状（三个位置）中量子模拟了2D Harper-Hofstadter（HH）晶格模型。 In addition to the usual transverse (out-of-plane) magnetic flux, piercing the surface of the tube, we threaded a longitudinal flux $Φ_{\rm L}$ down the axis of the tube This geometry evokes an Aharonov-Bohm interferometer, where noise in $Φ_{\rm L}$ would readily decohere the interference present in trajectories encircling the 管子。我们只有当横向通量是通量量子的有理比例时才能观察到这种行为，并且明显地发现，对于非理性分数，不存在逆转。此外，在横向通量的合理值下，我们表明，噪声纵向通量上的时间演变平均与附近不合理通量的时间演化相匹配。因此，AHARONOV-BOHM干涉仪的吸引人的直观图片不足。取而代之的是，我们通过将HH模型转换为动量空间Aubry-André模型的集合来定量解释我们的观察结果。
We quantum-simulated the 2D Harper-Hofstadter (HH) lattice model in a highly elongated tube geometry -- three sites in circumference -- using an atomic Bose-Einstein condensate. In addition to the usual transverse (out-of-plane) magnetic flux, piercing the surface of the tube, we threaded a longitudinal flux $Φ_{\rm L}$ down the axis of the tube This geometry evokes an Aharonov-Bohm interferometer, where noise in $Φ_{\rm L}$ would readily decohere the interference present in trajectories encircling the tube. We observe this behavior only when transverse flux is a rational fraction of the flux-quantum, and remarkably find that for irrational fractions the decoherence is absent. Furthermore, at rational values of transverse flux, we show that the time evolution averaged over the noisy longitudinal flux matches the time evolution at nearby irrational fluxes. Thus, the appealing intuitive picture of an Aharonov-Bohm interferometer is insufficient. Instead, we quantitatively explain our observations by transforming the HH model into a collection of momentum-space Aubry-André models.
