Entanglement purification without controlled-NOT gates by using the natural dynamics of spin chains

TL;DR

This paper introduces a protocol for entanglement purification in spin-1/2 particles using natural spin interactions and single-spin measurements, avoiding complex gate operations, which is practical for solid-state quantum systems.

Contribution

It demonstrates that natural spin-spin interactions, including the isotropic Heisenberg interaction, can be used for entanglement purification without controlled-NOT gates, requiring only S_z-measurements.

Findings

Purifies entanglement using natural spin dynamics.

Heisenberg interaction suffices for at least three pairs.

Applicable to realistic solid-state quantum systems.

Abstract

We present a simple protocol to purify bipartite entanglement in spin-1/2 particles by utilizing only natural spin-spin interactions, i.e. those that can commonly be realized in realistic physical systems, and S_z-measurements on single spins. Even the standard isotropic Heisenberg interaction is shown to be sufficient to purify mixed state entanglement if there are at least three pairs of spins. This approach could be useful for quantum information processing in solid-state-based systems.