Detecting Entanglement via Split Spectroscopy in Many-Body Systems

TL;DR

This paper introduces split spectroscopy as a practical method for detecting entanglement in many-body quantum systems, linking spectral features to entanglement structure and phase transitions, with an experimental protocol for Rydberg atoms.

Contribution

It proposes a novel split spectroscopy technique for entanglement detection and demonstrates its effectiveness in identifying quantum phase transitions in many-body systems.

Findings

Split spectroscopy shows a delta-function peak for triseparable states.

Spectral entropy indicates quantum phase transitions.

Protocol applicable to Rydberg atom arrays.

Abstract

Quantum entanglement is recognized as a fundamental resource in quantum information processing and is essential for understanding quantum many-body physics. However, experimentally detecting entanglement, particularly in many-particle quantum states, remains a significant challenge. Here, we propose split spectroscopy as an experimentally feasible technique for detecting entanglement of eigenstates in quantum many-body systems. We demonstrate the split spectroscopy exhibits a single delta-function peak if and only if the investigated eigenstate is triseparable. Our framework is illustrated using two paradigmatic spin models that undergo quantum phase transitions. Furthermore, we show that the spectral entropy serves as a powerful indicator of quantum phase transitions and captures the scaling behavior of entanglement. Finally, we present an experimental protocol using Rydberg atom arrays.