By keeping quantum states as unit vectors, the transformations are all unitary.
通过保持量子态是单位向量，变换就都是幺正的。
2
The variational relations of the internal excited states of polaron with coupling strength and magnetic field were derived by using the linear combination operator and unitary transformation methods.
应用线性组合算符和幺正变换方法，得出了极化子内部激发态与耦合强度和磁场的关系。
3
We have investigated the properties of entanglement by criterion of separability (non-entanglement) and equivalence of quantum states under local unitary transformations.