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arXiv 2102.10564hep-th
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二次拉格朗日量的平移对称性

Translational symmetries of quadratic lagrangians

Andrea Barducci, Roberto Casalbuoni

摘要:

在本文中,我们表明,一个二次拉格朗日量,没有约束,包含普通的时间导数的顺序$N$动力学变量$m$,有$2mN$对称性,包括在翻译的变量与解决方案的运动方程。我们明确地构造了这些变换的生成元,并证明了它们满足Heisenberg代数。我们还分析了其他具体的情况下,没有包括在我们以前的声明:克莱因-戈登拉格朗日,$N$费米振荡器和狄拉克拉格朗日。在第一种情况下,系统描述的方程涉及偏导数,第二种情况下描述的格拉斯曼变量和第三个显示这两个功能。此外,费米振子和狄拉克场拉格朗日量导致第二类约束。我们证明,也在这最后两种情况下,有平移对称性,我们构造的代数的发电机。对于克莱因-戈登的情况下,我们发现一个连续版本的海森堡代数,而在其他情况下,格拉斯曼发电机满足,量子化后,费米创建和湮灭运营商的代数。

英文摘要:

In this paper we show that a quadratic lagrangian, with no constraints, containing ordinary time derivatives up to the order $m$ of $N$ dynamical variables, has $2mN$ symmetries consisting in the translation of the variables with solutions of the equations of motion. We construct explicitly the generators of these transformations and prove that they satisfy the Heisenberg algebra. We also analyse other specific cases which are not included in our previous statement: the Klein-Gordon lagrangian, $N$ Fermi oscillators and the Dirac lagrangian. In the first case, the system is described by an equation involving partial derivatives, the second case is described by Grassmann variables and the third shows both features. Furthermore, the Fermi oscillator and the Dirac field lagrangians lead to second class constraints. We prove that also in these last two cases there are translational symmetries and we construct the algebra of the generators. For the Klein-Gordon case we find a continuum version of the Heisenberg algebra, whereas in the other cases, the Grassmann generators satisfy, after quantization, the algebra of the Fermi creation and annihilation operators.

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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