High-dimensional quantum gates using full-field spatial modes of photons

Understand

Unitary transformations are the fundamental building blocks of gates and operations in quantum information processing allowing the complete manipulation of quantum systems in a coherent manner.

• In the case of photons, optical elements that can perform unitary transformations are readily available only for some degrees of freedom, e.g.
• wave plates for polarisation.
• However for high-dimensional states encoded in the transverse spatial modes of light, performing arbitrary unitary transformations remains a challenging task for both theoretical proposals and actual implementations.