论文标题
通过条件在先验知识上进行的代表性学习中的物理发现:铁电域动态的应用
Physical discovery in representation learning via conditioning on prior knowledge: applications for ferroelectric domain dynamics
论文作者
论文摘要
电子,扫描探针,光学和化学成像和光谱的最新进展产生了包含复杂系统结构和功能信息的定制数据集。在许多情况下,所得数据集由低维的简单表示形式为基础,该表示编码数据中的可变性因素。表示学习方法旨在发现这些可变性因素,理想情况下将它们与相关的物理机制联系起来。但是,通常,识别与实际物理机制相对应的潜在变量的任务非常复杂。在这里,我们探讨了一种基于对已知(连续)物理参数的数据进行调节的方法,并将其与基于不变的变异自动编码器的先前介绍的方法进行了比较。条件变化自动编码器(CVAE)方法不依赖不变变换的存在,因此可以更大的灵活性和适用性。有趣的是,CVAE允许在条件变量的原始域之外进行有限的外推。但是,与已知真正的物理机制的情况相比,这种外推的限制是有限的,并且可变性的物理因素可以完全散布。我们进一步表明,如果条件向量与数据的可变性相关,则引入已知条件会导致潜在分布的简化,从而可以分离相关的物理因素。我们最初使用合成数据集上的1D和2D示例证明了这种方法,然后将其扩展到对通过Piezoresponse Force显微镜可视化的铁电域动力学的实验数据分析。
Recent advances in electron, scanning probe, optical, and chemical imaging and spectroscopy yield bespoke data sets containing the information of structure and functionality of complex systems. In many cases, the resulting data sets are underpinned by low-dimensional simple representations encoding the factors of variability within the data. The representation learning methods seek to discover these factors of variability, ideally further connecting them with relevant physical mechanisms. However, generally the task of identifying the latent variables corresponding to actual physical mechanisms is extremely complex. Here, we explore an approach based on conditioning the data on the known (continuous) physical parameters, and systematically compare it with the previously introduced approach based on the invariant variational autoencoders. The conditional variational autoencoders (cVAE) approach does not rely on the existence of the invariant transforms, and hence allows for much greater flexibility and applicability. Interestingly, cVAE allows for limited extrapolation outside of the original domain of the conditional variable. However, this extrapolation is limited compared to the cases when true physical mechanisms are known, and the physical factor of variability can be disentangled in full. We further show that introducing the known conditioning results in the simplification of the latent distribution if the conditioning vector is correlated with the factor of variability in the data, thus allowing to separate relevant physical factors. We initially demonstrate this approach using 1D and 2D examples on a synthetic dataset and then extend it to the analysis of experimental data on ferroelectric domain dynamics visualized via Piezoresponse Force Microscopy.