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.

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运输诱导的多量子点系统中核场波动的抑制

来自随机波动的核自旋集合的磁噪声是许多多量子点多电子自旋量子位退相干的主要来源。在这里，我们详细研究了直流电流对双核和三核量子点耦合的电子核自旋动力学的影响，这些量子点已调整为保利自旋封锁状态。我们考虑具有和不具有显着自旋轨道耦合的两个系统，发现在所有情况下，电子流都可以诱发动态核自旋极化过程，该过程有效地抑制了相邻点上的核极化梯度。由于这些梯度恰好是在量子位空间中有害作用的核场的组成部分，