High Fidelity Artificial Quantum Thermal State Generation using Encoded Coherent States

TL;DR

This paper demonstrates a method for generating high-fidelity artificial thermal states using encoded coherent states, verified through quantum state tomography with fidelity exceeding 0.98.

Contribution

It introduces a novel encoding technique for creating thermal states that are indistinguishable from natural thermal noise, verified experimentally.

Findings

Achieved state fidelity F>0.98 with theoretical thermal states.

Successfully reconstructed density matrices for engineered thermal states.

Demonstrated indistinguishability of engineered states from natural thermal noise.

Abstract

Quantum steganography is a powerful method for information security where communications between a sender and receiver are disguised as naturally occurring noise in a channel. We encoded the phase and amplitude of weak coherent laser states such that a third party monitoring the communications channel, measuring the flow of optical states through the channel, would see an amalgamation of states indistinguishable from thermal noise light. Using quantum state tomography, we experimentally reconstructed the density matrices for artificially engineered thermal states and spontaneous emission from an optical amplifier and verified a state fidelity F>0.98 when compared with theoretical thermal states.