High photon number entangled states and coherent state superposition from the extreme-ultraviolet to the far infrared

TL;DR

This paper theoretically demonstrates the generation of high photon number entangled states and optical cat states across a broad spectral range using high harmonic generation, advancing quantum optics and information science.

Contribution

It introduces a novel method to produce high photon number entangled states and superpositions in the extreme-ultraviolet to far infrared range via high harmonic generation.

Findings

All field modes in high harmonic generation are entangled.

Generation of high photon number optical cat states across a broad spectrum.

States can be used for quantum tests, information processing, and sensing.

Abstract

We present a theoretical demonstration on the generation of entangled coherent states and of coherent state superpositions, with photon numbers and frequencies orders of magnitude higher than those provided by the current technology. This is achieved by utilizing a quantum mechanical multimode description of the single- and two-color intense laser field driven process of high harmonic generation in atoms. It is found that all field modes involved in the high harmonic generation process are entangled, and upon performing a quantum operation, leads to the generation of high photon number optical cat states spanning from the far infrared to the extreme-ultraviolet spectral region. This provides direct insights into the quantum mechanical properties of the optical field in intense laser matter interaction. Finally, these states can be considered as a new resource for fundamental tests of quantum theory, quantum information processing or sensing with non-classical states of light.