Signals of multiparty entanglement and holography

TL;DR

This paper investigates signals of multiparty entanglement in quantum states, especially within holographic models, revealing substantial entanglement in some states and short-range entanglement in others, with new signals proposed for higher-party entanglement.

Contribution

It introduces new signals for detecting four- and higher-party entanglement and explores their properties in holographic states within AdS/CFT correspondence.

Findings

Multiparty entanglement signals are generally non-zero in holographic states.

Signals become small in the large-horizon limit of multiboundary wormholes.

Substantial multiparty entanglement is revealed in the AdS vacuum and wormhole states.

Abstract

We study multiparty entanglement signals, which are functions of a quantum state that are non-zero only when the state has multiparty entanglement. We consider known signals of three- and four-party entanglement, and propose new signals for four- and higher-party entanglement. We make some remarks on their general properties, but mainly focus on using holographic states in AdS$_3/$CFT$_2$ as a test case to explore their properties. For both the AdS vacuum and multiboundary wormhole states, we find that the multiparty entanglement signals are generically non-zero and of order one in units of the central charge of the dual CFT, revealing substantial multiparty entanglement. In the large-horizon limit of multiboundary wormhole states, however, the signals for three or more parties become small indicating the short-range nature of entanglement.