标题： 非指数隧穿效应由于平均场引起的尾状结构 显示英文标题

标题： Non-exponential tunneling due to mean-field induced swallowtails

摘要： 通常，能级在控制参数变化时会发生改变，但不会发生分岔。 分岔可能导致能量谱中出现环或燕尾形状。 支持燕尾形状的最简单的量子哈密顿量是一个非线性的$2 \times 2$哈密顿量，其非对角线元素不为零，而对角线元素依赖于两个状态的粒子数差。 本研究通过使用移动的一维光晶格中的超冷原子实验实现了这样的哈密顿量。 观察到了自束缚和非指数隧穿概率，这是支持燕尾形状带结构的标志性特征。 理论与实验之间的一致性验证了光晶格系统作为一个强大的平台，用于研究例如 约瑟夫森结物理和环形几何中的超流性。 显示英文摘要

摘要： Typically, energy levels change without bifurcating in response to a change of a control parameter. Bifurcations can lead to loops or swallowtails in the energy spectrum. The simplest quantum Hamiltonian that supports swallowtails is a non-linear $2 \times 2$ Hamiltonian with non-zero off-diagonal elements and diagonal elements that depend on the population difference of the two states. This work implements such a Hamiltonian experimentally using ultracold atoms in a moving one-dimensional optical lattice. Self-trapping and non-exponential tunneling probabilities, a hallmark signature of band structures that support swallowtails, are observed. The good agreement between theory and experiment validates the optical lattice system as a powerful platform to study, e.g., Josephson junction physics and superfluidity in ring-shaped geometries.