Quantitative complementarity between local and nonlocal character of quantum states in a three-qubit system

TL;DR

This paper experimentally investigates the quantitative trade-off between local and nonlocal quantum properties in three-qubit states using a four-way interferometer, revealing complementarity relations in an NMR quantum processor.

Contribution

It introduces a method to quantify and verify local versus nonlocal character trade-offs in three-qubit states through experimental measurements.

Findings

Verified complementarity relations experimentally

Measured complete entanglement as qubit-subsystem entanglement

Demonstrated quantitative bounds on local and nonlocal properties

Abstract

Local or nonlocal character of quantum states can be quantified and is subject to various bounds that can be formulated as complementarity relations. Here, we investigate the local vs. nonlocal character of pure three-qubit states by a four-way interferometer. The complete entanglement in the system can be measured as the entanglement of a specific qubit with the subsystem consisting of the other two qubits. The quantitative complementarity relations are verified experimentally in an NMR quantum information processor.