Week 4: Conductance from fluctuation

Conductance from fluctuation: listening to a resistor at equilibrium (Datta Ch. 5)

With no voltage, electrons still hop through a one-level resistor in both directions at random. Each crossing is a current pulse of height q/t lasting t (Fig. 5.3). The average current is zero, but its fluctuation C_I is not, and the fluctuation-dissipation theorem says G₀ = C_I/2kT (Eq. 5.4).

Level ε − μ₀ Temperature T Small bias V

Average current ⟨I⟩–

Fluctuation C_I = Var(Q)/T_w–

G₀ from noise, C_I/2kT–

G₀ theory (q²/t) f₀(1−f₀)/kT–