Open nQubit System as a Quantum Computer with FourValued Logic
Abstract
In this paper we generalize the usual model of quantum computer to a model in which the state is an operator of density matrix and the gates are general superoperators (quantum operations), not necessarily unitary. A mixed state (operator of density matrix) of n twolevel quantum system (open or closed nqubit system) is considered as an element of $4^{n}$dimensional operator Hilbert space (Liouville space). It allows to use quantum computer (circuit) model with 4valued logic. The gates of this model are general superoperators which act on nququats state. Ququat is quantum state in a 4dimensional (operator) Hilbert space. Unitary twovalued logic gates and quantum operations for nqubit open system are considered as fourvalued logic gates acting on nququats. We discuss properties of quantum 4valued logic gates. In the paper we study universality for quantum fourvalued logic gates.
 Publication:

arXiv eprints
 Pub Date:
 December 2001
 arXiv:
 arXiv:quantph/0112023
 Bibcode:
 2001quant.ph.12023T
 Keywords:

 Quantum Physics
 EPrint:
 25 pages, LaTeX