Kitaev quantum spin liquids host Majorana fermions via the fractionalization of spins. In a magnetic field, the Majorana fermions were predicted to comprise a topological state, which has attracted great attention by the discovery of the half-quantized thermal Hall conductivity. Nevertheless, a reliable theory remains elusive for the field effect, especially at finite temperature. Here we present unbiased large-scale numerical results for the Kitaev model in a wide range of magnetic field and temperature. We find that the unconventional paramagnetic region showing fractional spin dynamics extends at finite temperature, far beyond the field range where the topological state is expected at zero temperature. Our results show the confinement-deconfinement behavior between the fractional Majorana excitations and the conventional magnons.

中文翻译：

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Kitaev模型中磁场引起的马洛纳-马农现象交叉：连续时间量子蒙特卡洛研究

Kitaev量子自旋液体通过自旋的分馏作用携带马约拉纳费米子。在磁场中，马约拉那费米子被预测为具有拓扑状态，通过发现半量化的热霍尔电导率引起了极大的关注。然而，对于场效应，尤其是在有限温度下，可靠的理论仍然难以捉摸。在这里，我们展示了在广泛的磁场和温度范围内，Kitaev模型的无偏差大规模数值结果。我们发现，显示分数自旋动力学的非常规顺磁区域在有限温度下延伸，远远超出了在零温度下预期拓扑状态的磁场范围。我们的结果表明，分数马约拉纳激发与常规磁振子之间的约束-解除约束行为。