AI 中文总结
该研究建立了非中心对称超导导线中热激活相滑移的理论，揭示其电阻具有磁手性各向异性，源于与超导二极管效应相同的Lifshitz不变量导致的势垒不对称性，并通过普适比率与二极管效率关联。
AI 中文摘要
在临界温度以下，窄超导线的电阻尾部由相滑移主导，这些相滑移在转变附近是热激活的，而在较低温度下则是量子的。我们发展了缺乏反演对称性的导线中热激活相滑移的理论，微观上将其建模为二维电子气形成的扩散导线，并具有面内磁场中的Rashba自旋轨道耦合。相滑移电阻获得磁手性各向异性：在固定电流下，它随磁场反转而变化；在固定磁场下，它随电流反转而变化，而线性响应电阻则根据Onsager互易关系保持场对称。这种非互易性源于相滑移激活势垒的不对称性，该不对称性在电流和磁场中均为奇函数。它由自由能的Lifshitz不变量产生，包括三次梯度项和动量奇四次顶点，以及由螺旋基态将偶梯度项提升为奇梯度项，这正是决定超导二极管效应的组合。因此，势垒不对称性通过一个普适数值比率由同一导线的二极管效率固定，无需可调参数。动力学Lifshitz不变量使序参量的弛豫和噪声具有非互易性，但仅在参数次主导层面上影响涨落前因子。由于不对称性存在于激活指数中，磁手性信号相对于二极管不对称性被势垒高度与温度之比放大，并表现为微分电阻迹线指数斜率的场反对称分裂，该迹线常用于识别热激活相滑移。
英文摘要
Resistive tails of narrow superconducting wires below the critical temperature are governed by phase slips, thermally activated near the transition and quantum at lower temperatures. We develop the theory of thermally activated phase slips in wires lacking inversion symmetry, modeled microscopically as a diffusive wire formed from a two-dimensional electron gas with Rashba spin-orbit coupling in an in-plane magnetic field. The phase-slip resistance acquires magnetochiral anisotropy: at fixed current it changes upon reversal of the field, and at fixed field upon reversal of the current, while the linear-response resistance remains field symmetric as required by Onsager reciprocity. The nonreciprocity originates from an asymmetry of the phase-slip activation barrier that is odd in both current and field. It is generated by the Lifshitz invariants of the free energy, the cubic gradient term and the momentum-odd quartic vertex, together with even gradient terms promoted to odd ones by the helical ground state, precisely the combination that determines the superconducting diode effect. The barrier asymmetry is therefore fixed by the diode efficiency of the same wire through a universal numerical ratio, with no adjustable parameters. The kinetic Lifshitz invariant, which makes relaxation and noise of the order parameter nonreciprocal, affects only the fluctuation prefactor at a parametrically subleading level. Because the asymmetry resides in the activation exponent, the magnetochiral signal is amplified relative to the diode asymmetry by the ratio of barrier height to temperature, and appears as a field-antisymmetric splitting of the exponential slopes of differential-resistance traces routinely used to identify thermally activated phase slips.
Comments14 pages, 2 figures
