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arXiv 2003.13454physics.class-ph
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无处不在的洛伦兹力

The Ubiquitous Lorentz Force

Clinton L Lewis

摘要:

在拉格朗日力学这一优雅的机械中,最小化拉格朗日量的作用积分提供了欧拉-拉格朗日运动方程。然而,两个关系定义了电流和能量动量的发散,并为欧拉-拉格朗日方程提供了另一种动机,而无需调用最小作用量原理所需的大量机制。这两个关系的推导过程中,只有局部微分运算的拉格朗日,并没有一个全球一体化定义的行动。这两个关系将电流和能量-动量的局部连续性方程(作为消失的发散)与洛伦兹力、对称性和欧拉-拉格朗日方程联系起来。欧拉-拉格朗日方程对这两种关系都是通用的,因此提供了足够的动机来接受运动方程。能量动量、力、电流、对称性和运动运动方程等核心概念之间的基本关系提供了教学上有趣的清晰度。学生将看到这些概念是如何相互关联的,以及每个概念的独立定义。

英文摘要:

Minimizing the Action integral of a Lagrangian provides the Euler-Lagrange equation of motion in the elegant machinery of Lagrangian Mechanics. However two relations define the divergence of current and energy-momentum, and provide an alternative motivation for the Euler-Lagrange equation without invoking the considerable machinery required for the principle of least Action. The derivation of these two relations proceeds with only local differential operations on the Lagrangian, and without a global integration defining an Action. The two relations connect local continuity equations (as a vanishing divergence) for current and energy-momentum to Lorentz force, symmetry, and the Euler-Lagrange equation. The Euler-Lagrange equation is common to both relations so providing sufficient motivation for acceptance as equations of motion. The essential relationships between the central concepts of energy-momentum, force, current, symmetry and equation of motion provide pedagogically interesting clarity. The student will see that how these concepts relate to each other as well as the definition of each concept in isolation.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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