Virtual excitations and entanglement dynamics and polygamy in three ultra-strongly coupled systems

TL;DR

This paper investigates the dynamics of virtual excitations and entanglement in three ultra-strongly coupled oscillators, revealing their interrelation, hierarchy, and violation of monogamy, with implications for quantum circuit modeling.

Contribution

It introduces a symplectic geometry approach to analyze Milburn dynamics of virtual excitations and entanglement in a three-oscillator system, highlighting their hierarchy and monogamy violation.

Findings

Excitations and entanglement have similar temporal profiles.

Extinction of excitations leads to separability.

Violation of monogamy of excitations akin to quantum discord.

Abstract

The Milburn dynamics of three nonresonant ultra-strongly coupled oscillators are resolved by using symplectic geometry. We look at the Milburn dynamics of virtual excitations and how they affect pairwise entanglement. It is found that the dynamics of excitations and entanglement experience similar profiles against time, physical parameters, and decoherence rate. Furthermore, we show that the extinction of excitations entails separability, which demonstrates the hierarchy between entanglement and virtual excitations. Additionally, we analyze the effects of physical parameters on the redistribution of virtual excitations among the three bi-partitions. As a result, we show the violation of the monogamy of excitations as in quantum discord. This implies that excitations can be considered as signatures of quantum correlations beyond entanglement. Besides, we emphasize that our treatment can be used to model coupled quantum circuits in real situations (with decoherence).