Upstream Neutral Modes in the Fractional Quantum Hall Effect Regime: Heat Waves or Coherent Dipoles
Upstream Neutral Modes in the Fractional Quantum Hall Effect Regime: Heat Waves or Coherent Dipoles
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DOI：
10.1103/physrevlett.108.226801
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发表时间：
2012-05-30
影响因子：
8.6
通讯作者：
Mahalu, Diana
中科院分区：
文献类型：
--
作者：
Gross, Yaron;Dolev, Merav;Mahalu, Diana
最近，通过测量由收缩（表示为N -> C）分割中性模后产生的电荷噪声，在各种分数量子霍尔态（nu = 2/3，nu = 3/5，nu = 8/3和nu = 5/2）中观察到了被预测存在于空穴共轭态中的反向传播（上游）手性中性边缘模。特别值得注意的是在nu = 5/2分数态中观察到这种模式，因为它揭示了状态波函数的非阿贝尔性质。然而，这些独特的，上游的，不带电的模式和微观过程中，他们产生散粒噪声的性质，是不理解的。在这里，我们研究无处不在的nu = 2/3状态和报告的两个主要观察：第一，中性模式的性质进行了测试的“碰撞”两种模式，从两个相反的来源，在一个狭窄的收缩。由此产生的电荷噪声与分区准粒子的局部加热是一致的。第二，下游充电模式由收缩的分割产生了双重过程，即，上游中性模式（C -> N）的出现。换句话说，分裂“空穴共轭”型准粒子将导致能量损失和退相干，能量被中性模带走。
Counterpropagating (upstream) chiral neutral edge modes, which were predicted to be present in hole-conjugate states, were observed recently in a variety of fractional quantum Hall states (nu = 2/3, nu = 3/5, nu = 8/3, and nu = 5/2), by measuring the charge noise that resulted after partitioning the neutral mode by a constriction (denoted, as N -> C). Particularly noticeable was the observation of such modes in the nu = 5/2 fractional state-as it sheds light on the non-Abelian nature of the state's wave function. Yet, the nature of these unique, upstream, chargeless modes and the microscopic process in which they generate shot noise, are not understood. Here, we study the ubiquitous nu = 2/3 state and report of two main observations: First, the nature of the neutral modes was tested by "colliding" two modes, emanating from two opposing sources, in a narrow constriction. The resultant charge noise was consistent with local heating of the partitioned quasiparticles. Second, partitioning of a downstream charge mode by a constriction gave birth to a dual process, namely, the appearance of an upstream neutral mode (C -> N). In other words, splitting "hole conjugated" type quasiparticles will lead to an energy loss and decoherence, with energy carried away by neutral modes.