论文标题
传输引起的多量子点系统中核场波动的抑制
Transport-induced suppression of nuclear field fluctuations in multi-quantum-dot systems
论文作者
论文摘要
随机波动的核自旋组合产生的磁噪声是许多多量子点多电体旋转量子矩的主导地位源。在这里，我们详细研究了直流电流对耦合的电子核自旋动力学的影响，该动力学以双重量子点和三重量子点调整为Pauli自旋封锁状态。我们考虑具有和没有明显自旋轨道耦合的系统，并发现在所有情况下，电子的流动都可以诱导动态核自旋极化过程，从而有效地抑制了相邻点上的核极化梯度。由于这些梯度正是在量子空间中有害起作用的核场的组成部分，因此我们认为这是一种直接的方式，可以将多电体旋转量子器中的相干时间延长至少一个数量级。
Magnetic noise from randomly fluctuating nuclear spin ensembles is the dominating source of decoherence for many multi-quantum-dot multielectron spin qubits. Here we investigate in detail the effect of a DC electric current on the coupled electron-nuclear spin dynamics in double and triple quantum dots tuned to the regime of Pauli spin blockade. We consider both systems with and without significant spin-orbit coupling and find that in all cases the flow of electrons can induce a process of dynamical nuclear spin polarization that effectively suppresses the nuclear polarization gradients over neighboring dots. Since exactly these gradients are the components of the nuclear fields that act harmfully in the qubit subspace, we believe that this presents a straightforward way to extend coherence times in multielectron spin qubits by at least one order of magnitude.
