A Synthesis Method for Quaternary Quantum Logic Circuits
  Synthesis of quaternary quantum circuits involves basic quaternary gates and logic operations in the quaternary quantum domain. In this paper, we propose new projection operations and quaternary logic gates for synthesizing quaternary logic functions. We also demonstrate the realization of the proposed gates using basic quantum quaternary operations. We then employ our synthesis method to design of quaternary adder and some benchmark circuits. Our results in terms of circuit cost, are better than the existing works. 
Sudhindu Bikash Mandal, Amlan Chakrabarti, Susmita Sur-Kolay
cs.OH quant-ph