论文标题
在动态不稳定的Bose-Einstein冷凝物中的Bogoliubov准粒子的完美传播和完美的反射
Perfect transmission and perfect reflection of Bogoliubov quasiparticles in a dynamically unstable Bose-Einstein condensate
论文作者
论文摘要
Bose-Einstein冷凝物（BEC）中的Nambu-Goldstone（NG）模式在零能量极限中传输了具有概率1的潜在屏障，这被称为异常隧道。在本文中，我们研究了动态不稳定的BEC中准颗粒的隧道特性。我们在动态不稳定的状态下准备一个多组分BEC（二进制和旋转1 BEC），并解决了从冷凝水的旋转波激发的隧道问题。我们发现，即使旋转波是NG模式，即使BEC动态不稳定，也会发生完美的传输。在这里，表现出完美传输的模式是动态不稳定的自旋波模式，它是Bogoliubov-De Gennes方程的纯仿制 - 元素值解决方案。因此，我们应该沿实际轴而不是虚轴采取零能量极限。我们还证明了在特征值的假想部分最大值的位置的动态不稳定模式的完美反射。在这种情况下，事件和反射波破坏性干扰，以及准粒子波函数的幅度得到了强烈抑制。我们从数值上确认完美的反射是动态不稳定模式的通用性质，与NG模式无关。
The Nambu-Goldstone (NG) mode in a Bose-Einstein condensate (BEC) transmits a potential barrier with probability 1 in the zero-energy limit, which is known as the anomalous tunneling. In this paper, we investigate the tunneling properties of quasiparticles in a dynamically unstable BEC. We prepare a multi-component BEC (binary and spin-1 BEC) in a dynamically unstable state and solve the tunneling problem of the spin-wave excitation from the condensate. We find that the perfect transmission occurs even when the BEC is dynamically unstable if the spin-wave is the NG mode. Here, the mode that exhibits the perfect transmission is the dynamically unstable spin-wave mode, which is a pure-imaginary-eigenvalue solution of the Bogoliubov-de Gennes equation. Hence, we should take the zero-energy limit along not the real axis but the imaginary axis. We also demonstrate the existence of the perfect reflection of a dynamically unstable mode at the point where the imaginary part of the eigenvalue takes its maximum. In this case, the incident and reflected waves destructively interfere, and the amplitude of the quasiparticle wave function is strongly suppressed. We numerically confirm that the perfect reflection is a generic nature of dynamically unstable modes and not related to the NG mode.
