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arXiv 0805.4487math-phmath.MP
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用含时哈密顿量求解冯·诺依曼方程。第一部分:方法

Solving the von Neumann equation with time-dependent Hamiltonian. Part I: Method

Maciej Kuna, Jan Naudts

摘要:

利用含时不变量的方法,可以显式地构造描述含时哈密顿系统量子时间演化的幺正算符U(t).我们澄清了李代数技术在这方面的作用,并阐述了SU(2)和SU(1,1)的理论。我们表明,被称为马格努斯展开和Wei-Norman展开的结构对应于旋转群的不同表示。当用欧拉角表示旋转时,得到了一个更简单的构造。许多应用程序被推迟到论文的第二部分。

英文摘要:

The unitary operators U(t), describing the quantum time evolution of systems with a time-dependent Hamiltonian, can be constructed in an explicit manner using the method of time-dependent invariants. We clarify the role of Lie-algebraic techniques in this context and elaborate the theory for SU(2) and SU(1,1). We show that the constructions known as Magnus expansion and Wei-Norman expansion correspond with different representations of the rotation group. A simpler construction is obtained when representing rotations in terms of Euler angles. The many applications are postponed to Part II of the paper.

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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