Extremal Density Matrices for the Expectation Value of a Qudit Hamiltonian

被引:3
作者
Castanos, O. [1 ]
Figueroa, A. [1 ]
Lopez, J. [1 ]
Lopez-Pena, R. [1 ]
机构
[1] Univ Nacl Autonoma Mexico, Inst Ciencias Nucl, Apartado Postal 70-543, Mexico City 04510, DF, Mexico
来源
QUANTUM FEST 2016 INTERNATIONAL CONFERENCE ON QUANTUM PHENOMENA, QUANTUM CONTROL AND QUANTUM OPTICS | 2017年 / 839卷
关键词
STATES; GEOMETRY;
D O I
10.1088/1742-6596/839/1/012012
中图分类号
O4 [物理学];
学科分类号
0702 ;
摘要
An algebraic procedure to find extremal density matrices for the expectation value of a finite Hamiltonian matrix is established. The extremal density matrices for pure states provide a complete description of the system, that is, its corresponding energy spectrum and projectors. For density matrices representing mixed states, one gets the most probable eigenstates that yield extremal mean values of the energy. The procedure uses mainly the stationary solutions of the von Neumann equation of motion, the orbits of the Hamiltonian, and the positivity conditions of the density matrix. The method is illustrated for matrix Hamiltonians of dimensions d = 2 and d = 3.
引用
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页数:10
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