Gate Modeling and Circuit Simulation

As with other sophisticated technologies in information processing, the practical implementation and use of electronic circuits is preceded by their mathematical modeling and simulation. Detailed calculations of physical parameters are employed to characterize individual circuit elements with respect to environmental conditions and manufacturing variations, but are difficult to scale to very large integrated circuits. In this context, a compact model captures the essence of a circuit's operation without unnecessary details. Such models express the expected outputs of each circuit component given its inputs, and are key to fast algorithms for simulating the functional behavior of the entire circuit: its speed, power dissipation, temperature distribution, etc. Simulation is thus an important prerequisite to validating the operation of the circuit.

This chapter discusses the modeling and simulation of classical digital circuits to introduce and motivate the methods used for quantum circuit simulation. Emphasis is placed on functional simulation and its use in formal verification of both combinational and sequential circuits.