Realizing controllable noise in photonic quantum information channels

TL;DR

This paper introduces methods to create controllable depolarizing channels for single photons using birefringent crystals, enabling better management of quantum decoherence in photonic quantum information systems.

Contribution

The paper presents novel schemes for constructing depolarizing channels with controllable properties, validated through quantum process tomography.

Findings

Three depolarizing schemes demonstrated successfully.

Experimental results align with theoretical models.

Enhanced control over photon depolarization achieved.

Abstract

Controlling the depolarization of light is a long-standing open problem. In recent years, many demonstrations have used the polarization of single photons to encode quantum information. The depolarization of these photons is equivalent to the decoherence of the quantum information they encode. We present schemes for building various depolarizing channels with controlled properties using birefringent crystals. Three such schemes are demonstrated and their effects on single photons are shown by quantum process tomography to be in good agreement with a theoretical model.