学术进展

Local unitary equivalence of arbitrary dimensional multipartite mixed quantum states

题目:

Local unitary equivalence of arbitrary dimensional multipartite mixed quantum states

作者:费少明 研究员 (通讯作者)

简介:

Local unitary equivalence is an important ingredient for quantifying and classifying entanglement. Verifying
whether or not two quantum states are local unitary equivalent is a crucial problem, where only the case of
multipartite pure states is solved. For mixed states, however, the verification of local unitary equivalence is still
a challenging problem. In this paper, based on the coefficient matrices of generalized Bloch representations
of quantum states, we find a variety of local unitary invariants for arbitrary-dimensional bipartite quantum
states. These invariants are operational and can be used as necessary conditions for verifying the local unitary
equivalence of two quantum states. Furthermore, we extend the construction to the arbitrary-dimensional
multipartite case. We finally apply these invariants to estimate concurrence, a vital entanglement measure,
showing the practicability of local unitary invariants in characterizing entanglement.