Linear-optics realization of channels for single-photon multimode qudits

TL;DR

This paper presents a linear-optical method for implementing arbitrary quantum channels on single-photon multimode qudits, enabling stochastic realization with high success probabilities using simple optical setups.

Contribution

It introduces a practical, undemanding scheme for stochastic quantum channel realization using linear optics, vacuum ancillas, and non-adaptive schemes, including success probability analysis.

Findings

Deterministic implementation of random-unitary channels.

Stochastic realization of non-unital channels.

Success probability linked to entanglement of the Choi-Jamiolkowski state.

Abstract

We propose and theoretically study a method for the stochastic realization of arbitrary quantum channels on multimode single-photon qudits. In order for our method to be undemanding in its implementation, we restrict our analysis to linear-optical techniques, vacuum ancillary states and non-adaptive schemes, but we allow for random switching between different optical networks. With our method it is possible to deterministically implement random-unitary channels and to stochastically implement general, non-unital channels. We provide an expression for the optimal probability of success of our scheme and calculate this quantity for specific examples like the qubit amplitude-damping channel. The success probability is shown to be related to the entanglement properties of the Choi-Jamiolkowski state isomorphic to the channel.