Energy in Circuit Theory

In this chapter we leave quantum physics and return to circuits

and circuit theory. The effect of tunneling and Coulomb blockade

will be modeled by (parasitic) lumped circuit elements. From a

classical physics and electromagnetic theory point of view using

Maxwell’s equations, the lumped circuit is only an approximation,

as was discussed in Chapter 3. It assumes steady-state currents

or a quasi-static approach. Energy is conserved, and if applied to

circuits that cannot radiate, Kirchhoff’s current and voltage laws

could be obtained. In this chapter concepts of energy in circuit

theory are briefly reviewed that play an important role in analyzing

and synthesizing circuits with tunneling elements. Notations and

definitions are introduced.