Efficient Bipartite Entanglement Detection Scheme with a Quantum Adversarial Solver

TL;DR

This paper introduces a quantum adversarial approach for efficient bipartite entanglement detection, utilizing parameterized quantum circuits and a game-theoretic framework, demonstrated on optical networks for small quantum states.

Contribution

It presents a novel quantum adversarial scheme reformulating entanglement detection as a two-player game with polynomial runtime complexity, suitable for near-term quantum devices.

Findings

Successfully implemented on a linear optical network

Effective detection of bipartite entanglement in 5-qubit pure states

Demonstrated detection in 2-qubit mixed states

Abstract

The recognition of entanglement states is a notoriously difficult problem when no prior information is available. Here, we propose an efficient quantum adversarial bipartite entanglement detection scheme to address this issue. Our proposal reformulates the bipartite entanglement detection as a two-player zero-sum game completed by parameterized quantum circuits, where a two-outcome measurement can be used to query a classical binary result about whether the input state is bipartite entangled or not. In principle, for an $N$-qubit quantum state, the runtime complexity of our proposal is $O(\text{poly}(N)T)$ with $T$ being the number of iterations. We experimentally implement our protocol on a linear optical network and exhibit its effectiveness to accomplish the bipartite entanglement detection for 5-qubit quantum pure states and 2-qubit quantum mixed states. Our work paves the way for using near-term quantum machines to tackle entanglement detection on multipartite entangled quantum systems.