We consider a metric consisting of a gravitational background part and an electromagnetic part. We show that the Lorentz force equations follow exactly from the geodesic equation for this metric and that in the Dirac gauge the Einstein-Hilbert action reduces to gravitation with electromagnetism as long as the background part is much stronger than the electromagnetic one.

中文翻译：

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关于强场的统一场论

我们考虑一个由引力背景部分和电磁部分组成的度量。我们表明，洛伦兹力方程完全遵循该度量的测地线方程，并且在狄拉克规范中，只要背景部分比电磁部分强得多，爱因斯坦-希尔伯特作用就可通过电磁作用降为重力。