The purpose of this paper is to compare the operations of silicon-based solid-state quantum computer with classical logic gate made of double-gate (DG) nano-MOSFETs. Quantum gates, such as quantum NOT gate, controlled-NOT (CNOT) and quantum register are studied. On the other hand, classical computer gates, such as NOT gate, NOR gate, NAND gate, XOR gate and XNOR gate are described. Silicon-based solid-state quantum computer operates well at extremely low cryogenic temperature (77K) as shown by oscillation of electron density profiles of the silicon-based nanodevices. Unitary matrix which specifies a valid quantum gate is proven in this study. The intrinsic delay of the classical NOT gate is calculated from simulation output data and the current-voltage (I-V) characteristic of the DG nano-MOSFET, which is used to construct the NOT gate, is plotted and studied. The motivation of this study is to investigate ways to implement quantum computer with silicon-based DG nano-MOSFET implanted with phosphorus donor atoms.
