Classical arithmetic logic unit embedded on reversible/quantum circuit

Abstract

Reversible circuit dissipates less heat than irreversible circuit. A promising use of reversible circuit may be embedding of reversible circuits in irreversible general purpose computers to allow low-power design. In this paper, we embed an n-bit classical ALU on reversible circuit, which can perform addition, subtraction, EXOR, EXNOR, AND, NAND, OR, NOR, and NOT operations on n-bit data. The quantum realization of our n-bit ALU requires 27n — 10 primitive quantum gates with quantum circuit width of 4n + 5. The known reversible n-bit ALU capable of performing only mod 2n addition, subtraction, negative subtraction, EXOR, and no-operation requires 22n — 10 primitive quantum gates with quantum circuit width of 2n + 5. With a marginal increase of quantum primitive gate count and nearly doubling the quantum circuit width, our ALU implements a larger set of operation needed for general purpose computing.