Toolbox for entanglement detection and fidelity estimation

TL;DR

This paper introduces efficient methods for entanglement detection and fidelity estimation in quantum states, enabling scalable and robust analysis for various quantum states with minimal experimental effort.

Contribution

It provides linear-scaling techniques for fidelity determination of GHZ and W states and introduces simple methods for other important quantum states.

Findings

Fidelity of GHZ and W states can be determined with effort increasing linearly with qubits.

Proposes robust methods for cluster states and decoherence-free subspace states.

Methods are practical for experimental quantum information tasks.

Abstract

The determination of the state fidelity and the detection of entanglement are fundamental problems in quantum information experiments. We investigate how these goals can be achieved with a minimal effort. We show that the fidelity of GHZ and W states can be determined with an effort increasing only linearly with the number of qubits. We also present simple and robust methods for other states, such as cluster states and states in decoherence-free subspaces.