Bi-directional mapping between polarization and spatially encoded photonic qutrits

TL;DR

This paper presents methods for mapping bi-photonic polarization-encoded qutrits to single-photon spatial modes, enabling arbitrary unitary operations with high success probability using linear optics and weak nonlinearity.

Contribution

It introduces two schemes for bi-directional mapping between polarization and spatially encoded photonic qutrits, enhancing quantum information processing capabilities.

Findings

Linear optics scheme achieves arbitrary U(3) operations with low success probability.

Adding weak nonlinearity significantly improves success probability.

Schemes are feasible with current experimental technology.

Abstract

Qutrits, the triple level quantum systems in various forms, have been proposed for quantum information processing recently. By the methods presented in this paper a bi-photonic qutrit, which is encoded with the polarizations of two photons in the same spatial-temporal mode, can be mapped to a single photon qutrit in spatial modes. It will make arbitrary unitary operation on such bi-photonic qutrit possible if we can also realize the inverse map to polarization space. Among the two schemes proposed in this paper, the one based only on linear optics realizes an arbitrary U(3) operation with a very small success probability. However, if added with weak nonlinearity, the success probability can be greatly improved. These schemes are feasible with the current experimental technology.