Measurable nonlocal effect of bipartite system during a local cyclic evolution of its subsystem

TL;DR

This paper proposes a measurable nonlocal effect in bipartite systems caused by local cyclic evolution, which varies with entanglement and can be observed in mixed states, demonstrated through a two-qubit example.

Contribution

It introduces a new nonlocal effect linked to local cyclic evolution and entanglement, with a proposed experimental measurement method.

Findings

Effect vanishes in pure disentangled states

Effect observed in certain mixed states

Effect correlates with entanglement degree

Abstract

In this letter, a nonlocal effect for a bipartite system which is induced by a local cyclic evolution of one of its subsystem is suggested. This effect vanishes when the system is at a disentangled pure state but can be observed for some disentangled mixed states. As a paradigm, we study the effect for the system of two qubits in detail. It is interesting that the effect is directly related to the degree of entanglement for pure state of qubit pairs. Furthermore, we suggest a Bell-type experiment to measure this nonlocal effect for qubit pairs.