The Hamiltonian of the system is the Driac operator which as a matrix differential operator is not semibounded from below.

系统的哈密顿函数是作为矩阵微分算子的狄拉克算子，它不是半有界的。

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In this paper, we get the self-adjointness of the product operators generated by different two differential expressions by operator theory and matrix calculation.

此前对微分算子的积算子自伴的研究主要集中于由同一个对称微分算式生成的两个或多个微分算子积的自伴问题上，取得了一些成果。

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