Quantum polarization optics

Project funded by Swedish Research Council (Project grant), grant 2011-04575_VR. Participating organisations named by the source: KTH, Royal Institute of Technology. Funded amount: SEK 3,540,000, as stated by the source. Runs 2011-01-01 to 2013-12-31. Keywords: Naturvetenskap, Natural Sciences, Fysik, Physical Sciences, Atom- och molekylfysik och optik, Atom and Molecular Physics and Optics. Source: OpenAIRE Graph, from the funder's project data (collected by OpenAIRE on 2025-12-05); national funding data, not CORDIS. Abstract given by the source: The polarization of light is the preferred degree of freedom in most applications of quantum information (qubit) transmission such as quantum cryptography or quantum computing. The reason is the polarization´s robustness against decoherence and dissipation, and the relative simplicity of polarization manipulation. However, a comprehensive theory, and understanding, of quantum polarization is still lacking. The prevailing theory, centered on the Stokes vector, only considers the first order moments of the Stokes operators. In quantum information applications, where polarization entangled states are often used, correlations are imperative, pointing to the fact that higher order moments need to be included in a proper description. Since polarization involves three degrees of freedom, the number of correlations grows rapidly with the moment order, and therefore moment tensors, multipole expansion, and/or generalized coherence matrices will have to form the theory´s core. Using the tensor invariants (under SU(2) transformations = polarization transformations) we hope to find suitable quantitative measures of polarization, moment order by moment order. To be useful, such a description must be accompanied by an experimental polarization tomography scheme. We shall also develop such a procedure and verify it by measurements. To this end we shall use photon twins, triplets and quadruplets generated by spontaneous emission down-conversion.

Original source.

Source: OpenAIRE Graph: projects of national funders, OpenAIRE, from the project data of Swedish Research Council. Retrieved 2026-10-28. Licence: Creative Commons Attribution 4.0 (OpenAIRE Graph). Selected metadata, adapted presentation; the publisher's record is authoritative. No endorsement by the source is implied. Licence: Creative Commons Attribution 4.0 (CC BY 4.0).

AI-assisted summary: The project "Quantum polarization optics" was funded by the Swedish Research Council with a grant of SEK 3,540,000, running from January 1, 2011, to December 31, 2013. It involves KTH, Royal Institute of Technology, and focuses on the polarization of light in quantum information applications. Suggested technology pillar: communication. Generated by AI from the public source text; it may contain errors and the original source is authoritative.