Vibrational enhancement of quadrature squeezing and phase sensitivity in resonance fluorescence

Jake Iles-Smith,Dara P S Mccutcheon,Ahsan Nazir

doi:10.1038/s41467-019-10909-3

Abstract

Vibrational environments are commonly considered to be detrimental to the optical emission properties of solid-state and molecular systems, limiting their performance within quantum information protocols. Given that such environments arise naturally it is important to ask whether they can instead be turned to our advantage. Here we show that vibrational interactions can be harnessed within resonance fluorescence to generate optical states with a higher degree of quadrature squeezing than in isolated atomic systems. Considering the example of a driven quantum dot coupled to phonons, we demonstrate that it is feasible to surpass the maximum level of squeezing theoretically obtainable in an isolated atomic system and indeed come close to saturating the fundamental upper bound on squeezing from a two-level emitter. We analyse the performance of these vibrationally-enhanced squeezed states in a phase estimation protocol, finding that for the same photon flux, they can outperform the single mode squeezed vacuum state.

Highlights

Vibrational environments are commonly considered to be detrimental to the optical emission properties of solid-state and molecular systems, limiting their performance within quantum information protocols
We have shown that interactions between a two-level emitter (TLE) and a vibrational environment can be harnessed to produce a source of quadrature squeezed light with levels of squeezing that would otherwise be impossible within resonance fluorescence
We have explored how these resonance fluorescence states perform in a phase estimation protocol

Summary

Introduction

Vibrational environments are commonly considered to be detrimental to the optical emission properties of solid-state and molecular systems, limiting their performance within quantum information protocols. In 1981, Walls and Zoller[14] investigated an intriguing source of non-Gaussian quadrature squeezing, which is generated in the multimode resonance fluorescence field of a driven two-level emitter (TLE), where the emitted photons are antibunched[15,16]. This was recently demonstrated experimentally using a semiconductor quantum dot platform[17], which offers the necessary high photon collection efficiency unobtainable in most atomic approaches[18,19,20]. We identify a scenario in which vibrational processes in solid-state emitters can be used to generate squeezed states and enhance phase sensitivity in a way not possible in their absence

Methods

Results

Conclusion