Multitype entanglement dynamics induced by exceptional points

TL;DR

This paper investigates how exceptional points in a non-Hermitian two-qubit system influence entanglement dynamics, revealing complex behaviors and transitions that depend on coupling strength and interaction type, with implications for quantum technologies.

Contribution

It introduces a generic model of coupled non-Hermitian qubits demonstrating multitype entanglement dynamics induced by exceptional points, including effects without external driving.

Findings

Entanglement dynamics differ across EP4' and EP2 in weak coupling.

Increasing coupling replaces EP4' with an additional EP2, altering entanglement behavior.

EP-induced entanglement changes can occur without external driving in Ising interactions.

Abstract

As a most important feature of non-Hermitian systems, exceptional points (EPs) lead to a variety of unconventional phenomena and applications. Here, we study a generic model composed of two coupled non-Hermitian qubits, the EPs can be easily obtained in this system by adjusting the driving amplitude applied to the qubits. The diverse entanglement dynamics on the two sides of the original fourth-order EP (EP4') and second order EP (EP2) can be observed simultaneously in the weak coupling regime. With the increase of the coupling strength, the EP4' is replaced by an additional EP2, leading to the disappearance of the entanglement dynamics changing induced by EP4' in the strong coupling regime. Considering the case of Ising type interaction, we also realize EP-induced entanglement dynamics changing without the driving field. Our study paves the way for the investigation of EP-induced quantum effects and applications of EP-related quantum technologies.