Stationary two-qubit entanglement mediated by one-dimensional plasmonic nanoarrays
Phys. Rev. B 114, 065410 – Published 9 July, 2026
DOI: https://doi.org/10.1103/vm4t-x91b
Abstract
Entanglement is one of the key measures of quantum correlations present in nanophotonic systems, with promising applications in quantum optics and beyond. Authors of previous studies have shown that the degree of entanglement between two quantum dot (QD) qubits is preserved when a metal nanoparticle (MNP) is used to mediate the interactions between the qubits. In this work, we investigate long-range plasmonic mediation of qubit-qubit entanglement by studying the impact of the number of mediating MNPs on stationary concurrence. Collinear and periodically spaced MNPs that satisfy the weak-coupling approximation are considered. An effective model that enables the derivation of the mediated interactions within the framework of cavity quantum electrodynamics is employed. Under weak driving at the single-particle resonance frequency, the model shows that odd-number arrays are more robust to entanglement decay. We attribute this to strong interqubit dissipative coupling as a result of a hybridized dipole plasmon resonating with the driving frequency in odd-number arrays. These arrays can sustain nonvanishing stationary entanglement beyond an interqubit spacing of 1 µm, opening the possibility of independent spatial optical probing of each QD.
