Local Numerical Range for a Class of 2 ⊗ d Hermitian Operators
نویسندگان
چکیده
A local numerical range is analyzed for a family of circulant observables and states of composite 2 ⊗ d systems. It is shown that for any 2 ⊗ d circulant operator O there exists a basis giving rise to the matrix representation with real non-negative off-diagonal elements. In this basis the problem of finding extremum of O on product vectors |x ⊗ |y ∈ C 2 ⊗ C d reduces to the corresponding problem in R 2 ⊗ R d. The final analytical result for d = 2 is presented.
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عنوان ژورنال:
- Open Syst. Inform. Dynam.
دوره 17 شماره
صفحات -
تاریخ انتشار 2010