The operator in parentheses in (3. 54) is called the laplacian operator . 在（354）的括号里的算符叫做拉普拉斯算符。
we will call the system with hamitonian the unperturbed system. 我们把具有哈密顿算符的体系叫做未微扰体系。
The nth power of an operator is defined to mean applying the operator n times in succession . 一个算符的n次幂定义为连续运用算符n次。
We won't run into any problem of non-commutativity in constructing these operators . 在构成这些算符时，我们不会陷入任何非对易性问题中。
For a system, hamiltonian is invariant under any translation of spatial coordinates . 对于一体系，哈密算符在任何空间坐标变换下是不变的。
We will later provide further justification of the choice (3. 24) for the momentum operator . 以后将对于选（324）为动量算符提供进一步的论证。
It would have made no difference in the final result whatever we first applied one operator or the other . 不管先用哪个算符，最后结果并无不同。
The basic dynamic variables are then the operators associated with the creation and annihilation of quanta . 基本动力学变数是与产生和消灭量子相联系的算符。
The procedure described above applies to the eigenvalues and eigenfunctions of any hermitian operator . 用上述运算方法也能求出任一厄密算符的本征值和本征函数。
Many texts define a hermitian operator as the following equation that satisfies for all well-behaved functions f and g . 许多教科书将厄米算符定义为对所有的品优函数f和g满足下式的算符。
