一类两体量子态的量子失谐解析解

Analytical Solutions of Quantum Discord for a Class of Two Body Quantum State

量子失谐概念最先由Olliver和Zurek于2001年提出,它是除量子纠缠外量子态之间非常重要的一种量子关联。由于任意态之间的量子失谐计算往往非常复杂,导致目前关于两体量子态的量子失谐计算主要针对两体X-态,而对非X-态的研究较少。基于冯·诺依曼熵和经典关联,给出了一类带5个参数的非X-型两体量子态的量子失谐表达式。通过将表达式转化为单变量函数,利用函数单调性,得出其显式的解析公式,并发现对一个已知的两体态都可以如此给出其量子失谐。

The concept of quantum discord was firstly proposed by Olliver and Zurek in2001. It is a very important quantum correlation between quantum states except quantum entanglement. The analytical calculation of quantum discord between qubits is often very complicated, so the calculation of the quantum discord is mainly for the X-states, the studies for the non-X-states are very few. We presented analytical formulae of a class of non-X-states with five parameters based on Von Neumann entropy and classical correlation. We converted the formulea into a univariate function and used the monotonicity of the function to derive its analytical explicit formula. We found that the quantum discord can be computed in this way for a known two qubits.