Generation of qudits and entangled qudits
Yongmin Li, Kuanshou Zhang, Kunchi Peng · Physical Review A · 2008
We propose schemes for the generation of $d$-level quantum states (qudits) and quantum entangled states of $N$ qudits by adopting the polarization degree of freedom of photons. Arbitrary qudits can be prepared by putting $d\ensuremath{-}1$ identical and independent photons (each with a given polarization) into a single spatial and temporal mode. Then, by using $N$ such qudits, linear optics, and proper projection measurements, quantum entangled states of $N$ qudits can be produced. The frequencies of the $N$ qudits can be identical or different according to the corresponding linear optics and projection measurements.