Displacement-enhanced continuous-variable entanglement concentration

TL;DR

This paper explores how local displacements can improve the efficiency of entanglement concentration in continuous-variable Gaussian states, especially for experimentally relevant split single-mode squeezed vacuum states.

Contribution

It introduces a displacement-enhanced photon subtraction protocol for split single-mode squeezed states, demonstrating improved entanglement concentration performance.

Findings

Local displacements enhance entanglement concentration.

Protocol is effective for split single-mode squeezed states.

Performance improves when displacements are applied to one or both modes.

Abstract

We study entanglement concentration of continuous variable Gaussian states by local photon subtractions enhanced by coherent displacements. Instead of the previously considered symmetric two-mode squeezed vacuum states, we investigate the protocol for input states in the form of split single-mode squeezed vacuum, i.e., states obtained by mixing a single-mode squeezed vacuum with a vacuum state on a beam splitter, which is an experimentally highly relevant configuration. We analyze two scenarios in which the displacement-enhanced photon subtraction is performed either only on one, or on both of the modes and show that local displacements can lead to improved performance of the concentration protocol.