Information Processing Using Three-Qubit and Qubit-Qutrit Encodings of Noncomposite Quantum Systems

We study quantum information properties of a seven-level system realized by a particle in a onedimensional square-well trap and discuss the features of encodings of seven-level systems in a form of three-qubit or qubit-qutrit systems. We use the three-qubit encoding of the system in order to investigate the subadditivity and strong subadditivity conditions for the particle's thermal state. We employ the qubit-qutrit encoding to suggest a single qudit algorithm for calculating the parity of a bit string. The results obtained indicate on the potential resource of multilevel systems for realization of quantum information processing.