Generating mixtures of spatial qubits

TL;DR

This paper extends a method for creating pure entangled spatial qudits to generate mixed states, demonstrated experimentally by producing a mixture of two spatial qubits using parametric down-conversion.

Contribution

It introduces a generalized technique for generating mixed states of spatial qubits, expanding upon previous pure state generation methods.

Findings

Successfully generated a mixture of two spatial qubits experimentally

Demonstrated the feasibility of creating mixed states of spatial qudits

Extended the theoretical framework for mixed state generation

Abstract

In a recent letter [Phys. Rev. Lett. 94, 100501 (2005)], we presented a scheme for generating pure entangled states of spatial qudits ($D$-dimensional quantum systems) by using the momentum transverse correlation of the parametric down-converted photons. In this work we discuss a generalization of this process to enable the creation of mixed states. With the technique proposed we experimentally generated a mixture of two spatial qubits.