Nonlinear chiral magnonic resonators: Toward magnonic neurons
Nonlinear chiral magnonic resonators: Toward magnonic neurons
复制标题
DOI：
10.1063/5.0149466
复制
发表时间：
2023-04
影响因子：
4
通讯作者：
K. Fripp;Y. Au;A. Shytov;V. Kruglyak
中科院分区：
文献类型：
--
作者：
K. Fripp;Y. Au;A. Shytov;V. Kruglyak
我们探讨手征磁振子共振器作为人工神经网络的基石。通过微磁模拟和分析建模，我们表明，限制在谐振器中的自旋波模式表现出强烈的非线性响应，由于能量集中时，共振激发入射自旋波。可以利用这种效应来实现网络中的人工神经元。因此，受限和传播的自旋波模式可以分别作为神经元和神经间的连接。对于适度的激发水平，该效应可以用共振频率的非线性偏移（“失谐”）来描述，这导致单色自旋波的振幅依赖性传输，这可以被利用来重新创建“S形”激活函数。在更强的激励水平下，非线性导致双稳态和滞后，类似于当激励强度超过由模式的衰减速率设定的阈值时在非线性振荡器中发生的那些。在磁振子谐振器中，后者包括由于与介质耦合而引起的吉尔伯特阻尼和辐射衰减。我们的模拟结果很好地描述了一个唯象模型，其中的非线性失谐的限制模式是其振幅的平方，而在介质中的传播是线性的。
We explore chiral magnonic resonators as building blocks of artificial neural networks. Via micromagnetic simulations and analytical modeling, we demonstrate that the spin-wave modes confined in the resonators exhibit a strongly nonlinear response owing to energy concentration when resonantly excited by incoming spin waves. This effect may be harnessed to implement an artificial neuron in a network. Therefore, the confined and propagating spin-wave modes can serve as neurons and interneural connections, respectively. For modest excitation levels, the effect can be described in terms of a nonlinear shift of the resonant frequency (“detuning”), which results in amplitude-dependent transmission of monochromatic spin waves, which may be harnessed to recreate a “sigmoid-like” activation function. At even stronger excitation levels, the nonlinearity leads to bistability and hysteresis, akin to those occurring in nonlinear oscillators when the excitation strength exceeds a threshold set by the decay rate of the mode. In magnonic resonators, the latter includes both the Gilbert damping and the radiative decay due to the coupling with the medium. The results of our simulations are well described by a phenomenological model in which the nonlinear detuning of the confined mode is quadratic in its amplitude, while the propagation in the medium is linear.