The fastest generation of multipartite entanglement with natural interactions

TL;DR

This paper investigates the minimal time required to generate highly entangled multipartite states using natural two-body interactions, revealing that larger systems do not necessarily need more time, with results based on numerical and analytical methods.

Contribution

It introduces state-dependent quantum speed limits for generating multipartite entanglement with natural interactions, focusing on symmetry constraints and system energy.

Findings

Entanglement generation time does not increase with the number of particles.

Natural interactions can produce complex entangled states efficiently.

Numerical and analytical methods validate the speed limits.

Abstract

Natural interactions among multiple quantum objects are fundamentally composed of two-body terms only. In contradistinction, single global unitaries that generate highly entangled states typically arise from Hamiltonians that couple multiple individual subsystems simultaneously. Here, we study the time to produce strongly nonclassical multipartite correlations with a single unitary generated by the natural interactions. We restrict the symmetry of two-body interactions to match the symmetry of the target states and focus on the fastest generation of multipartite entangled Greenberger-Horne-Zeilinger (GHZ), W, Dicke and absolutely maximally entangled (AME) states for up to seven qubits. These results are obtained by constraining the energy in the system and accordingly can be seen as state-dependent quantum speed limits for symmetry-adjusted natural interactions. They give rise to a counter-intuitive effect where the creation of particular entangled states with an increasing number of particles does not require more time. The methods used rely on extensive numerical simulations and analytical estimations.