书目名称 | Density Matrix Theory and Applications | 编辑 | Karl Blum | 视频video | | 图书封面 |  | 描述 | Quantum mechanics has been mostly concerned with those states of systems that are represented by state vectors. In many cases, however, the system of interest is incompletely determined; for example, it may have no more than a certain probability of being in the precisely defined dynamical state characterized by a state vector. Because of this incomplete knowledge, a need for statistical averaging arises in the same sense as in classical physics. The density matrix was introduced by J. von Neumann in 1927 to describe statistical concepts in quantum mechanics. The main virtue of the density matrix is its analytical power in the construction of general formulas and in the proof of general theorems. The evaluation of averages and probabilities of the physical quantities characterizing a given system is extremely cumbersome without the use of density matrix techniques. The representation of quantum mechanical states by density matrices enables the maximum information available on the system to be expressed in a compact manner and hence avoids the introduction of unnecessary vari ables. The use of density matrix methods also has the advantage of providing a uniform treatment of all qua | 出版日期 | Book 1981 | 关键词 | Matrix; Matrix Theory; density; fields; information; mechanics; physics; quantum mechanics; quantum theory; s | 版次 | 1 | doi | https://doi.org/10.1007/978-1-4615-6808-7 | isbn_ebook | 978-1-4615-6808-7 | copyright | Springer Science+Business Media New York 1981 |
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