Faculty of Physics, Moscow M.V.Lomonosov State University
At the present time S.P.Kulik develops the concept of quantum quarts or ququarts. It has been demonstrated that these objects can be realized using polarization states of frequency degenerate collinear biphoton field. Coherent superposition of four orthogonal basic biphoton states emitted from four nonlinear crystals implements photonic four-state system. However even single nonlinear crystal is enough to generate a particular set of ququarts which can be used for quantum key distribution. The protocols of quantum tomography of qutrits/ququarts were proposed and realized. The next stage consists in implementation of quantum key distribution protocol based on qutrits and ququarts.
Another branch of scientific interests relates to physical properties of Schmidt decomposition and entanglement quantification for bipartite multidimensional states. Such states can be implemented via spontaneous parametric down conversion. In particular spatial and frequency degrees of freedom serve as a base for realization of multidimensional states. Complete control over spatial/frequency entanglement is a subject of current research.
The latest activities relate to practical realization of quantum key distribution protocol based on temporal coding of information as well as realization of relativistic quantum cryptography protocol.
Another problem to be realized is adaptive quantum state/process tomography.
The last branch of my activity covers problem of quantum calculations/simulations. We are trying to realize it with neutral atoms and photonic chips.